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• NoSQL Memcached API for MySQL: Latest Updates

  - by Mat Keep

  With data volumes exploding, it is vital to be able to ingest and query data at high speed. For this reason, MySQL has implemented NoSQL interfaces directly to the InnoDB and MySQL Cluster (NDB) storage engines, which bypass the SQL layer completely. Without SQL parsing and optimization, Key-Value data can be written directly to MySQL tables up to 9x faster, while maintaining ACID guarantees. In addition, users can continue to run complex queries with SQL across the same data set, providing real-time analytics to the business or anonymizing sensitive data before loading to big data platforms such as Hadoop, while still maintaining all of the advantages of their existing relational database infrastructure. This and more is discussed in the latest Guide to MySQL and NoSQL where you can learn more about using the APIs to scale new generations of web, cloud, mobile and social applications on the world's most widely deployed open source database The native Memcached API is part of the MySQL 5.6 Release Candidate, and is already available in the GA release of MySQL Cluster. By using the ubiquitous Memcached API for writing and reading data, developers can preserve their investments in Memcached infrastructure by re-using existing Memcached clients, while also eliminating the need for application changes. Speed, when combined with flexibility, is essential in the world of growing data volumes and variability. Complementing NoSQL access, support for on-line DDL (Data Definition Language) operations in MySQL 5.6 and MySQL Cluster enables DevOps teams to dynamically update their database schema to accommodate rapidly changing requirements, such as the need to capture additional data generated by their applications. These changes can be made without database downtime. Using the Memcached interface, developers do not need to define a schema at all when using MySQL Cluster. Lets look a little more closely at the Memcached implementations for both InnoDB and MySQL Cluster. Memcached Implementation for InnoDB The Memcached API for InnoDB is previewed as part of the MySQL 5.6 Release Candidate. As illustrated in the following figure, Memcached for InnoDB is implemented via a Memcached daemon plug-in to the mysqld process, with the Memcached protocol mapped to the native InnoDB API. Figure 1: Memcached API Implementation for InnoDB With the Memcached daemon running in the same process space, users get very low latency access to their data while also leveraging the scalability enhancements delivered with InnoDB and a simple deployment and management model. Multiple web / application servers can remotely access the Memcached / InnoDB server to get direct access to a shared data set. With simultaneous SQL access, users can maintain all the advanced functionality offered by InnoDB including support for Foreign Keys, XA transactions and complex JOIN operations. Benchmarks demonstrate that the NoSQL Memcached API for InnoDB delivers up to 9x higher performance than the SQL interface when inserting new key/value pairs, with a single low-end commodity server supporting nearly 70,000 Transactions per Second. Figure 2: Over 9x Faster INSERT Operations The delivered performance demonstrates MySQL with the native Memcached NoSQL interface is well suited for high-speed inserts with the added assurance of transactional guarantees. You can check out the latest Memcached / InnoDB developments and benchmarks here You can learn how to configure the Memcached API for InnoDB here Memcached Implementation for MySQL Cluster Memcached API support for MySQL Cluster was introduced with General Availability (GA) of the 7.2 release, and joins an extensive range of NoSQL interfaces that are already available for MySQL Cluster Like Memcached, MySQL Cluster provides a distributed hash table with in-memory performance. MySQL Cluster extends Memcached functionality by adding support for write-intensive workloads, a full relational model with ACID compliance (including persistence), rich query support, auto-sharding and 99.999% availability, with extensive management and monitoring capabilities. All writes are committed directly to MySQL Cluster, eliminating cache invalidation and the overhead of data consistency checking to ensure complete synchronization between the database and cache. Figure 3: Memcached API Implementation with MySQL Cluster Implementation is simple: 1. The application sends reads and writes to the Memcached process (using the standard Memcached API). 2. This invokes the Memcached Driver for NDB (which is part of the same process) 3. The NDB API is called, providing for very quick access to the data held in MySQL Cluster’s data nodes. The solution has been designed to be very flexible, allowing the application architect to find a configuration that best fits their needs. It is possible to co-locate the Memcached API in either the data nodes or application nodes, or alternatively within a dedicated Memcached layer. The benefit of this flexible approach to deployment is that users can configure behavior on a per-key-prefix basis (through tables in MySQL Cluster) and the application doesn’t have to care – it just uses the Memcached API and relies on the software to store data in the right place(s) and to keep everything synchronized. Using Memcached for Schema-less Data By default, every Key / Value is written to the same table with each Key / Value pair stored in a single row – thus allowing schema-less data storage. Alternatively, the developer can define a key-prefix so that each value is linked to a pre-defined column in a specific table. Of course if the application needs to access the same data through SQL then developers can map key prefixes to existing table columns, enabling Memcached access to schema-structured data already stored in MySQL Cluster. Conclusion Download the Guide to MySQL and NoSQL to learn more about NoSQL APIs and how you can use them to scale new generations of web, cloud, mobile and social applications on the world's most widely deployed open source database See how to build a social app with MySQL Cluster and the Memcached API from our on-demand webinar or take a look at the docs Don't hesitate to use the comments section below for any questions you may have 

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• SPARC M7 Chip - 32 cores - Mind Blowing performance

  - by Angelo-Oracle

  The M7 Chip Oracle just announced its Next Generation Processor at the HotChips HC26 conference. As the Tech Lead in our Systems Division's Partner group, I had a front row seat to the extraordinary price performance advantage of Oracle current T5 and M6 based systems. Partner after partner tested  these systems and were impressed with it performance. Just read some of the quotes to see what our partner has been saying about our hardware. We just announced our next generation processor, the M7. This has 32 cores (up from 16-cores in T5 and 12-cores in M6). With 20 nm technology  this is our most advanced processor. The processor has more cores than anything else in the industry today. After the Sun acquisition Oracle has released 5 processors in 4 years and this is the 6th.  The S4 core  The M7 is built using the foundation of the S4 core. This is the next generation core technology. Like its predecessor, the S4 has 8 dynamic threads. It increases the frequency while maintaining the Pipeline depth. Each core has its own fine grain power estimator that keeps the core within its power envelop in 250 nano-sec granularity. Each core also includes Software in Silicon features for Application Acceleration Support. Each core includes features to improve Application Data Integrity, with almost no performance loss. The core also allows using part of the Virtual Address to store meta-data.  User-Level Synchronization Instructions are also part of the S4 core. Each core has 16 KB Instruction and 16 KB Data L1 cache. The Core Clusters  The cores on the M7 chip are organized in sets of 4-core clusters. The core clusters share  L2 cache.  All four cores in the complex share 256 KB of 4 way set associative L2 Instruction Cache, with over 1/2 TB/s of throughput. Two cores share 256 KB of 8 way set associative L2 Data Cache, with over 1/2 TB/s of throughput. With this innovative Core Cluster architecture, the M7 doubles core execution bandwidth. to maximize per-thread performance.  The Chip  Each  M7 chip has 8 sets of these core-clusters. The chip has 64 MB on-chip L3 cache. This L3 caches is shared among all the cores and is partitioned into 8 x 8 MB chunks. Each chunk is  8-way set associative cache. The aggregate bandwidth for the L3 cache on the chip is over 1.6TB/s. Each chip has 4 DDR4 memory controllers and can support upto 16 DDR4 DIMMs, allowing for 2 TB of RAM/chip. The chip also includes 4 internal links of PCIe Gen3 I/O controllers.  Each chip has 7 coherence links, allowing for 8 of these chips to be connected together gluelessly. Also 32 of these chips can be connected in an SMP configuration. A potential system with 32 chips will have 1024 cores and 8192 threads and 64 TB of RAM.  Software in Silicon The M7 chip has many built in Application Accelerators in Silicon. These features will be exposed to our Software partners using the SPARC Accelerator Program.  The M7  has built-in logic to decompress data at the speed of memory access. This means that applications can directly work on compressed data in memory increasing the data access rates. The VA Masking feature allows the use of part of the virtual address to store meta-data.  Realtime Application Data Integrity The Realtime Application Data Integrity feature helps applications safeguard against invalid, stale memory reference and buffer overflows. The first 4-bits if the Pointer can be used to store a version number and this version number is also maintained in the memory & cache lines. When a pointer accesses memory the hardware checks to make sure the two versions match. A SEGV signal is raised when there is a mismatch. This feature can be used by the Database, applications and the OS.  M7 Database In-Memory Query Accelerator The M7 chip also includes a In-Silicon Query Engines.  These accelerate tasks that work on In-Memory Columnar Vectors. Oracle In-Memory options stores data in Column Format. The M7 Query Engine can speed up In-Memory Format Conversion, Value and Range Comparisons and Set Membership lookups. This engine can work on Compressed data - this means not only are we accelerating the query performance but also increasing the memory bandwidth for queries.  SPARC Accelerated Program  At the Hotchips conference we also introduced the SPARC Accelerated Program to provide our partners and third part developers access to all the goodness of the M7's SPARC Application Acceleration features. Please get in touch with us if you are interested in knowing more about this program. 

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• Why lock-free data structures just aren't lock-free enough

  - by Alex.Davies

  Today's post will explore why the current ways to communicate between threads don't scale, and show you a possible way to build scalable parallel programming on top of shared memory. The problem with shared memory Soon, we will have dozens, hundreds and then millions of cores in our computers. It's inevitable, because individual cores just can't get much faster. At some point, that's going to mean that we have to rethink our architecture entirely, as millions of cores can't all access a shared memory space efficiently. But millions of cores are still a long way off, and in the meantime we'll see machines with dozens of cores, struggling with shared memory. Alex's tip: The best way for an application to make use of that increasing parallel power is to use a concurrency model like actors, that deals with synchronisation issues for you. Then, the maintainer of the actors framework can find the most efficient way to coordinate access to shared memory to allow your actors to pass messages to each other efficiently. At the moment, NAct uses the .NET thread pool and a few locks to marshal messages. It works well on dual and quad core machines, but it won't scale to more cores. Every time we use a lock, our core performs an atomic memory operation (eg. CAS) on a cell of memory representing the lock, so it's sure that no other core can possibly have that lock. This is very fast when the lock isn't contended, but we need to notify all the other cores, in case they held the cell of memory in a cache. As the number of cores increases, the total cost of a lock increases linearly. A lot of work has been done on "lock-free" data structures, which avoid locks by using atomic memory operations directly. These give fairly dramatic performance improvements, particularly on systems with a few (2 to 4) cores. The .NET 4 concurrent collections in System.Collections.Concurrent are mostly lock-free. However, lock-free data structures still don't scale indefinitely, because any use of an atomic memory operation still involves every core in the system. A sync-free data structure Some concurrent data structures are possible to write in a completely synchronization-free way, without using any atomic memory operations. One useful example is a single producer, single consumer (SPSC) queue. It's easy to write a sync-free fixed size SPSC queue using a circular buffer*. Slightly trickier is a queue that grows as needed. You can use a linked list to represent the queue, but if you leave the nodes to be garbage collected once you're done with them, the GC will need to involve all the cores in collecting the finished nodes. Instead, I've implemented a proof of concept inspired by this intel article which reuses the nodes by putting them in a second queue to send back to the producer. * In all these cases, you need to use memory barriers correctly, but these are local to a core, so don't have the same scalability problems as atomic memory operations. Performance tests I tried benchmarking my SPSC queue against the .NET ConcurrentQueue, and against a standard Queue protected by locks. In some ways, this isn't a fair comparison, because both of these support multiple producers and multiple consumers, but I'll come to that later. I started on my dual-core laptop, running a simple test that had one thread producing 64 bit integers, and another consuming them, to measure the pure overhead of the queue. So, nothing very interesting here. Both concurrent collections perform better than the lock-based one as expected, but there's not a lot to choose between the ConcurrentQueue and my SPSC queue. I was a little disappointed, but then, the .NET Framework team spent a lot longer optimising it than I did. So I dug out a more powerful machine that Red Gate's DBA tools team had been using for testing. It is a 6 core Intel i7 machine with hyperthreading, adding up to 12 logical cores. Now the results get more interesting. As I increased the number of producer-consumer pairs to 6 (to saturate all 12 logical cores), the locking approach was slow, and got even slower, as you'd expect. What I didn't expect to be so clear was the drop-off in performance of the lock-free ConcurrentQueue. I could see the machine only using about 20% of available CPU cycles when it should have been saturated. My interpretation is that as all the cores used atomic memory operations to safely access the queue, they ended up spending most of the time notifying each other about cache lines that need invalidating. The sync-free approach scaled perfectly, despite still working via shared memory, which after all, should still be a bottleneck. I can't quite believe that the results are so clear, so if you can think of any other effects that might cause them, please comment! Obviously, this benchmark isn't realistic because we're only measuring the overhead of the queue. Any real workload, even on a machine with 12 cores, would dwarf the overhead, and there'd be no point worrying about this effect. But would that be true on a machine with 100 cores? Still to be solved. The trouble is, you can't build many concurrent algorithms using only an SPSC queue to communicate. In particular, I can't see a way to build something as general purpose as actors on top of just SPSC queues. Fundamentally, an actor needs to be able to receive messages from multiple other actors, which seems to need an MPSC queue. I've been thinking about ways to build a sync-free MPSC queue out of multiple SPSC queues and some kind of sign-up mechanism. Hopefully I'll have something to tell you about soon, but leave a comment if you have any ideas.

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• Scripting out Contained Database Users

  - by Argenis

    Today’s blog post comes from a Twitter thread on which @SQLSoldier, @sqlstudent144 and @SQLTaiob were discussing the internals of contained database users. Unless you have been living under a rock, you’ve heard about the concept of contained users within a SQL Server database (hit the link if you have not). In this article I’d like to show you that you can, indeed, script out contained database users and recreate them on another database, as either contained users or as good old fashioned logins/server principals as well. Why would this be useful? Well, because you would not need to know the password for the user in order to recreate it on another instance. I know there is a limited number of scenarios where this would be necessary, but nonetheless I figured I’d throw this blog post to show how it can be done. A more obscure use case: with the password hash (which I’m about to show you how to obtain) you could also crack the password using a utility like hashcat, as highlighted on this SQLServerCentral article. The Investigation SQL Server uses System Base Tables to save the password hashes of logins and contained database users. For logins it uses sys.sysxlgns, whereas for contained database users it leverages sys.sysowners. I’ll show you what I do to figure this stuff out: I create a login/contained user, and then I immediately browse the transaction log with, for example, fn_dblog. It’s pretty obvious that only two base tables touched by the operation are sys.sysxlgns, and also sys.sysprivs – the latter is used to track permissions. If I connect to the DAC on my instance, I can query for the password hash of this login I’ve just created. A few interesting things about this hash. This was taken on my laptop, and I happen to be running SQL Server 2014 RTM CU2, which is the latest public build of SQL Server 2014 as of time of writing. In 2008 R2 and prior versions (back to 2000), the password hashes would start with 0x0100. The reason why this changed is because starting with SQL Server 2012 password hashes are kept using a SHA512 algorithm, as opposed to SHA-1 (used since 2000) or Snefru (used in 6.5 and 7.0). SHA-1 is nowadays deemed unsafe and is very easy to crack. For regular SQL logins, this information is exposed through the sys.sql_logins catalog view, so there is really no need to connect to the DAC to grab an SID/password hash pair. For contained database users, there is (currently) no method of obtaining SID or password hashes without connecting to the DAC. If we create a contained database user, this is what we get from the transaction log: Note that the System Base Table used in this case is sys.sysowners. sys.sysprivs is used as well, and again this is to track permissions. To query sys.sysowners, you would have to connect to the DAC, as I mentioned previously. And this is what you would get: There are other ways to figure out what SQL Server uses under the hood to store contained database user password hashes, like looking at the execution plan for a query to sys.dm_db_uncontained_entities (Thanks, Robert Davis!) SIDs, Logins, Contained Users, and Why You Care…Or Not. One of the reasons behind the existence of Contained Users was the concept of portability of databases: it is really painful to maintain Server Principals (Logins) synced across most shared-nothing SQL Server HA/DR technologies (Mirroring, Availability Groups, and Log Shipping). Often times you would need the Security Identifier (SID) of these logins to match across instances, and that meant that you had to fetch whatever SID was assigned to the login on the principal instance so you could recreate it on a secondary. With contained users you normally wouldn’t care about SIDs, as the users are always available (and synced, as long as synchronization takes place) across instances. Now you might be presented some particular requirement that might specify that SIDs synced between logins on certain instances and contained database users on other databases. How would you go about creating a contained database user with a specific SID? The answer is that you can’t do it directly, but there’s a little trick that would allow you to do it. Create a login with a specified SID and password hash, create a user for that server principal on a partially contained database, then migrate that user to contained using the system stored procedure sp_user_migrate_to_contained, then drop the login. CREATE LOGIN <login_name> WITH PASSWORD = <password_hash> HASHED, SID = <sid> ; GO USE <partially_contained_db>; GO CREATE USER <user_name> FROM LOGIN <login_name>; GO EXEC sp_migrate_user_to_contained @username = <user_name>, @rename = N’keep_name’, @disablelogin = N‘disable_login’; GO DROP LOGIN <login_name>; GO Here’s how this skeleton would look like in action: And now I have a contained user with a specified SID and password hash. In my example above, I renamed the user after migrated it to contained so that it is, hopefully, easier to understand. Enjoy!

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• OS Analytics with Oracle Enterprise Manager (by Eran Steiner)

  - by Zeynep Koch

  Oracle Enterprise Manager Ops Center provides a feature called "OS Analytics". This feature allows you to get a better understanding of how the Operating System is being utilized. You can research the historical usage as well as real time data. This post will show how you can benefit from OS Analytics and how it works behind the scenes. The recording of our call to discuss this blog is available here: https://oracleconferencing.webex.com/oracleconferencing/ldr.php?AT=pb&SP=MC&rID=71517797&rKey=4ec9d4a3508564b3Download the presentation here See also: Blog about Alert Monitoring and Problem Notification Blog about Using Operational Profiles to Install Packages and other content Here is quick summary of what you can do with OS Analytics in Ops Center: View historical charts and real time value of CPU, memory, network and disk utilization Find the top CPU and Memory processes in real time or at a certain historical day Determine proper monitoring thresholds based on historical data Drill down into a process details Where to start To start with OS Analytics, choose the OS asset in the tree and click the Analytics tab. You can see the CPU utilization, Memory utilization and Network utilization, along with the current real time top 5 processes in each category (click the image to see a larger version):  In the above screen, you can click each of the top 5 processes to see a more detailed view of that process. Here is an example of one of the processes: One of the cool things is that you can see the process tree for this process along with some port binding and open file descriptors. Next, click the "Processes" tab to see real time information of all the processes on the machine: An interesting column is the "Target" column. If you configured Ops Center to work with Enterprise Manager Cloud Control, then the two products will talk to each other and Ops Center will display the correlated target from Cloud Control in this table. If you are only using Ops Center - this column will remain empty. The "Threshold" tab is particularly helpful - you can view historical trends of different monitored values and based on the graph - determine what the monitoring values should be: You can ask Ops Center to suggest monitoring levels based on the historical values or you can set your own. The different colors in the graph represent the current set levels: Red for critical, Yellow for warning and Blue for Information, allowing you to quickly see how they're positioned against real data. It's important to note that when looking at longer periods, Ops Center smooths out the data and uses averages. So when looking at values such as CPU Usage, try shorter time frames which are more detailed, such as one hour or one day. Applying new monitoring values When first applying new values to monitored attributes - a popup will come up asking if it's OK to get you out of the current Monitoring Policy. This is OK if you want to either have custom monitoring for a specific machine, or if you want to use this current machine as a "Gold image" and extract a Monitoring Policy from it. You can later apply the new Monitoring Policy to other machines and also set it as a default Monitoring Profile. Once you're done with applying the different monitoring values, you can review and change them in the "Monitoring" tab. You can also click the "Extract a Monitoring Policy" in the actions pane on the right to save all the new values to a new Monitoring Policy, which can then be found under "Plan Management" -> "Monitoring Policies". Visiting the past Under the "History" tab you can "go back in time". This is very helpful when you know that a machine was busy a few hours ago (perhaps in the middle of the night?), but you were not around to take a look at it in real time. Here's a view into yesterday's data on one of the machines: You can see an interesting CPU spike happening at around 3:30 am along with some memory use. In the bottom table you can see the top 5 CPU and Memory consumers at the requested time. Very quickly you can see that this spike is related to the Solaris 11 IPS repository synchronization process using the "pkgrecv" command. The "time machine" doesn't stop here - you can also view historical data to determine which of the zones was the busiest at a given time: Under the hood The data collected is stored on each of the agents under /var/opt/sun/xvm/analytics/historical/ An "os.zip" file exists for the main OS. Inside you will find many small text files, named after the Epoch time stamp in which they were taken If you have any zones, there will be a file called "guests.zip" containing the same small files for all the zones, as well as a folder with the name of the zone along with "os.zip" in it If this is the Enterprise Controller or the Proxy Controller, you will have folders called "proxy" and "sat" in which you will find the "os.zip" for that controller The actual script collecting the data can be viewed for debugging purposes as well: On Linux, the location is: /opt/sun/xvmoc/private/os_analytics/collect If you would like to redirect all the standard error into a file for debugging, touch the following file and the output will go into it: # touch /tmp/.collect.stderr   The temporary data is collected under /var/opt/sun/xvm/analytics/.collectdb until it is zipped. If you would like to review the properties for the Analytics, you can view those per each agent in /opt/sun/n1gc/lib/XVM.properties. Find the section "Analytics configurable properties for OS and VSC" to view the Analytics specific values. I hope you find this helpful! Please post questions in the comments below. Eran Steiner

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• Using SQL Source Control with Fortress or Vault &ndash; Part 1

  - by AjarnMark

  I am fanatical when it comes to managing the source code for my company.  Everything that we build (in source form) gets put into our source control management system.  And I’m not just talking about the UI and middle-tier code written in C# and ASP.NET, but also the back-end database stuff, which at times has been a pain.  We even script out our Scheduled Jobs and keep a copy of those under source control. The UI and middle-tier stuff has long been easy to manage as we mostly use Visual Studio which has integration with source control systems built in.  But the SQL code has been a little harder to deal with.  I have been doing this for many years, well before Microsoft came up with Data Dude, so I had already established a methodology that, while not as smooth as VS, nonetheless let me keep things well controlled, and allowed doing my database development in my tool of choice, Query Analyzer in days gone by, and now SQL Server Management Studio.  It just makes sense to me that if I’m going to do database development, let’s use the database tool set.  (Although, I have to admit I was pretty impressed with the demo of Juneau that Don Box did at the PASS Summit this year.)  So as I was saying, I had developed a methodology that worked well for us (and I’ll probably outline in a future post) but it could use some improvement. When Solutions and Projects were first introduced in SQL Management Studio, I thought we were finally going to get our same experience that we have in Visual Studio.  Well, let’s say I was underwhelmed by Version 1 in SQL 2005, and apparently so were enough other people that by the time SQL 2008 came out, Microsoft decided that Solutions and Projects would be deprecated and completely removed from a future version.  So much for that idea. Then I came across SQL Source Control from Red-Gate.  I have used several tools from Red-Gate in the past, including my favorites SQL Compare, SQL Prompt, and SQL Refactor.  SQL Prompt is worth its weight in gold, and the others are great, too.  Earlier this year, we upgraded from our earlier product bundles to the new Developer Bundle, and in the process added SQL Source Control to our collection.  I thought this might really be the golden ticket I was looking for.  But my hopes were quickly dashed when I discovered that it only integrated with Microsoft Team Foundation Server and Subversion as the source code repositories.  We have been using SourceGear’s Vault and Fortress products for years, and I wholeheartedly endorse them.  So I was out of luck for the time being, although there were a number of people voting for Vault/Fortress support on their feedback forum (as did I) so I had hope that maybe next year I could look at it again. But just a couple of weeks ago, I was pleasantly surprised to receive notice in my email that Red-Gate had an Early Access version of SQL Source Control that worked with Vault and Fortress, so I quickly downloaded it and have been putting it through its paces.  So far, I really like what I see, and I have been quite impressed with Red-Gate’s responsiveness when I have contacted them with any issues or concerns that I have had.  I have had several communications with Gyorgy Pocsi at Red-Gate and he has been immensely helpful and responsive. I must say that development with SQL Source Control is very different from what I have been used to.  This post is getting long enough, so I’ll save some of the details for a separate write-up, but the short story is that in my regular mode, it’s all about the script files.  Script files are King and you dare not make a change to the database other than by way of a script file, or you are in deep trouble.  With SQL Source Control, you make your changes to your development database however you like.  I still prefer writing most of my changes in T-SQL, but you can also use any of the GUI functionality of SSMS to make your changes, and SQL Source Control “manages” the script for you.  Basically, when you first link your database to source control, the tool generates scripts for every primary object (tables and their indexes are together in one script, not broken out into separate scripts like DB Projects do) and those scripts are checked into your source control.  So, if you needed to, you could still do a GET from your source control repository and build the database from scratch.  But for the day-to-day work, SQL Source Control uses the same technique as SQL Compare to determine what changes have been made to your development database and how to represent those in your repository scripts.  I think that once I retrain myself to just work in the database and quit worrying about having to find and open the right script file, that this will actually make us more efficient. And for deployment purposes, SQL Source Control integrates with the full SQL Compare utility to produce a synchronization script (or do a live sync).  This is similar in concept to Microsoft’s DACPAC, if you’re familiar with that. If you are not currently keeping your database development efforts under source control, definitely examine this tool.  If you already have a methodology that is working for you, then I still think this is worth a review and comparison to your current approach.  You may find it more efficient.  But remember that the version which integrates with Vault/Fortress is still in pre-release mode, so treat it with a little caution.  I have found it to be fairly stable, but there was one bug that I found which had inconvenient side-effects and could have really been frustrating if I had been running this on my normal active development machine.  However, I can verify that that bug has been fixed in a more recent build version (did I mention Red-Gate’s responsiveness?).

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• College Courses through distance learning

  - by Matt

  I realize this isn't really a programming question, but didn't really know where to post this in the stackexchange and because I am a computer science major i thought id ask here. This is pretty unique to the programmer community since my degree is about 95% programming. I have 1 semester left, but i work full time. I would like to finish up in December, but to make things easier i like to take online classes whenever I can. So, my question is does anyone know of any colleges that offer distance learning courses for computer science? I have been searching around and found a few potential classes, but not sure yet. I would like to gather some classes and see what i can get approval for. Class I need: Only need one C SC 437 Geometric Algorithms C SC 445 Algorithms C SC 473 Automata Only need one C SC 452 Operating Systems C SC 453 Compilers/Systems Software While i only need of each of the above courses i still need to take two more electives. These also have to be upper 400 level classes. So i can take multiple in each category. Some other classes I can take are: CSC 447 - Green Computing CSC 425 - Computer Networking CSC 460 - Database Design CSC 466 - Computer Security I hoping to take one or two of these courses over the summer. If not, then online over the regular semester would be ok too. Any help in helping find these classes would be awesome. Maybe you went to a college that offered distance learning. Some of these classes may be considered to be graduate courses too. Descriptions are listed below if you need. Thanks! Descriptions Computer Security This is an introductory course covering the fundamentals of computer security. In particular, the course will cover basic concepts of computer security such as threat models and security policies, and will show how these concepts apply to specific areas such as communication security, software security, operating systems security, network security, web security, and hardware-based security. Computer Networking Theory and practice of computer networks, emphasizing the principles underlying the design of network software and the role of the communications system in distributed computing. Topics include routing, flow and congestion control, end-to-end protocols, and multicast. Database Design Functions of a database system. Data modeling and logical database design. Query languages and query optimization. Efficient data storage and access. Database access through standalone and web applications. Green Computing This course covers fundamental principles of energy management faced by designers of hardware, operating systems, and data centers. We will explore basic energy management option in individual components such as CPUs, network interfaces, hard drives, memory. We will further present the energy management policies at the operating system level that consider performance vs. energy saving tradeoffs. Finally we will consider large scale data centers where energy management is done at multiple layers from individual components in the system to shutting down entries subset of machines. We will also discuss energy generation and delivery and well as cooling issues in large data centers. Compilers/Systems Software Basic concepts of compilation and related systems software. Topics include lexical analysis, parsing, semantic analysis, code generation; assemblers, loaders, linkers; debuggers. Operating Systems Concepts of modern operating systems; concurrent processes; process synchronization and communication; resource allocation; kernels; deadlock; memory management; file systems. Algorithms Introduction to the design and analysis of algorithms: basic analysis techniques (asymptotics, sums, recurrences); basic design techniques (divide and conquer, dynamic programming, greedy, amortization); acquiring an algorithm repertoire (sorting, median finding, strong components, spanning trees, shortest paths, maximum flow, string matching); and handling intractability (approximation algorithms, branch and bound). Automata Introduction to models of computation (finite automata, pushdown automata, Turing machines), representations of languages (regular expressions, context-free grammars), and the basic hierarchy of languages (regular, context-free, decidable, and undecidable languages). Geometric Algorithms The study of algorithms for geometric objects, using a computational geometry approach, with an emphasis on applications for graphics, VLSI, GIS, robotics, and sensor networks. Topics may include the representation and overlaying of maps, finding nearest neighbors, solving linear programming problems, and searching geometric databases.

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• C# async and actors

  - by Alex.Davies

  If you read my last post about async, you might be wondering what drove me to write such odd code in the first place. The short answer is that .NET Demon is written using NAct Actors. Actors are an old idea, which I believe deserve a renaissance under C# 5. The idea is to isolate each stateful object so that only one thread has access to its state at any point in time. That much should be familiar, it's equivalent to traditional lock-based synchronization. The different part is that actors pass "messages" to each other rather than calling a method and waiting for it to return. By doing that, each thread can only ever be holding one lock. This completely eliminates deadlocks, my least favourite concurrency problem. Most people who use actors take this quite literally, and there are plenty of frameworks which help you to create message classes and loops which can receive the messages, inspect what type of message they are, and process them accordingly. But I write C# for a reason. Do I really have to choose between using actors and everything I love about object orientation in C#? Type safety Interfaces Inheritance Generics As it turns out, no. You don't need to choose between messages and method calls. A method call makes a perfectly good message, as long as you don't wait for it to return. This is where asynchonous methods come in. I have used NAct for a while to wrap my objects in a proxy layer. As long as I followed the rule that methods must always return void, NAct queued up the call for later, and immediately released my thread. When I needed to get information out of other actors, I could use EventHandlers and callbacks (continuation passing style, for any CS geeks reading), and NAct would call me back in my isolated thread without blocking the actor that raised the event. Using callbacks looks horrible though. To remind you: m_BuildControl.FilterEnabledForBuilding(    projects,    enabledProjects = m_OutOfDateProjectFinder.FilterNeedsBuilding(        enabledProjects,             newDirtyProjects =             {                 ....... Which is why I'm really happy that NAct now supports async methods. Now, methods are allowed to return Task rather than just void. I can await those methods, and C# 5 will turn the rest of my method into a continuation for me. NAct will run the other method in the other actor's context, but will make sure that when my method resumes, we're back in my context. Neither actor was ever blocked waiting for the other one. Apart from when they were actually busy doing something, they were responsive to concurrent messages from other sources. To be fair, you could use async methods with lock statements to achieve exactly the same thing, but it's ugly. Here's a realistic example of an object that has a queue of data that gets passed to another object to be processed: class QueueProcessor {    private readonly ItemProcessor m_ItemProcessor = ...     private readonly object m_Sync = new object();    private Queue<object> m_DataQueue = ...    private List<object> m_Results = ...     public async Task ProcessOne() {         object data = null;         lock (m_Sync)         {             data = m_DataQueue.Dequeue();         }         var processedData = await m_ItemProcessor.ProcessData(data); lock (m_Sync)         {             m_Results.Add(processedData);         }     } } We needed to write two lock blocks, one to get the data to process, one to store the result. The worrying part is how easily we could have forgotten one of the locks. Compare that to the version using NAct: class QueueProcessorActor : IActor { private readonly ItemProcessor m_ItemProcessor = ... private Queue<object> m_DataQueue = ... private List<object> m_Results = ... public async Task ProcessOne()     {         // We are an actor, it's always thread-safe to access our private fields         var data = m_DataQueue.Dequeue();         var processedData = await m_ItemProcessor.ProcessData(data);         m_Results.Add(processedData);     } } You don't have to explicitly lock anywhere, NAct ensures that your code will only ever run on one thread, because it's an actor. Either way, async is definitely better than traditional synchronous code. Here's a diagram of what a typical synchronous implementation might do: The left side shows what is running on the thread that has the lock required to access the QueueProcessor's data. The red section is where that lock is held, but doesn't need to be. Contrast that with the async version we wrote above: Here, the lock is released in the middle. The QueueProcessor is free to do something else. Most importantly, even if the ItemProcessor sometimes calls the QueueProcessor, they can never deadlock waiting for each other. So I thoroughly recommend you use async for all code that has to wait a while for things. And if you find yourself writing lots of lock statements, think about using actors as well. Using actors and async together really takes the misery out of concurrent programming.

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• Common usecases and techniques when integrating a 3rd party application with Oracle Sales Cloud

  - by asantaga

  Over the last year or so I've see a lot of partners migrating and integrate their applications with Oracle Sales Cloud. Interestingly I'd say 60% of the partners use the same set of design patterns over and over again. Most of the time I see that they want to embed their application into Oracle Sales Cloud, within a tab usually, perhaps click on a link to their application (passing some piece of data + credentials) and then within their application update sales cloud again using webservices. Here are some examples of the different use-cases I've seen , and how partners are embedding their applications into Sales Cloud, NB : The following examples use the "Desktop" User Interface rather than the Newer "Simplified User Interface", I'll update the sample application soon but the integration patterns are precisely the same Use Case 1 :  Navigator "Link out" to third party application This is an example of where the developer has added a link to the global navigator and this links out to the 3rd Party Application. Typically one doesn't pass any contextual data with the exception of perhaps user credentials, or better still JWT Token. Techniques Used   Adding Link to Menu Item Using JWT Token in Sales Cloud Use Case 2 : Application Embedded within the Sales Cloud Dashboard Within the Oracle Sales Cloud application there is a tab called "Sales", within this tab its possible to embed a SubTab and embed a iFrame pointing to your application. To do this the developer simply needs to edit the page in customization mode, add the tab and then add the iFrame, simples! The developer can pass credentials/JWT Token and some other pieces of data but not object data (ie the current OpportunityID etc)  Techniques Used Adding a page to the dashboard  Using JWT Token in Sales Cloud  Use Case 3 : Embedding a Tab and Context Linking out from a Sales Cloud object to the 3rd party application In this usecase the developer embeds two components into Oracle Sales Cloud. The first is a SubTab showing summary data to the user (a quote in our case) and then secondly a hyperlink, (although it could be a button) which when clicked navigates the user to the 3rd party application. In this case the developer almost always passes context specific data (i.e. the opportunityId) and a security token (username password combo or JWT Token). The third party application usually takes the data, perhaps queries more data using the Sales Cloud SOAP/WebService interface and then displays the resulting mashup to the user for further processing. When the user has finished their work in the 3rd party application they normally navigate back to Oracle Sales Cloud using what's called a "DeepLink", ie taking them back to the object [opportunity in our case] they came from. This image visually shows a "Happy Path" a user may follow, and combines linking out to an application , webservice calls and deep linking back to Sales Cloud. Techniques Used Extending a SalesCloud application with a custom button Using JWT Token in Sales Cloud Extending Oracle Sales Cloud [Opportnity] with a custom tab exposing External Content Retrieving Data from Oracle Sales cloud using WebServices Coding some groovy script to generate the URLs required (Doc 1571200.1 on MyOracle Support) DeepLinking to specific Oracle Sales Cloud Pages (Doc 1516151.1 on My Oracle Support) Use-Case 4 :  Server Side processing/synchronization This usecase focuses on the Server Side processing of data, in this case synchronizing data. Here the 3rd party application is running on a "timer", e.g. cron or similar, and when triggered it queries data from Oracle Sales Cloud, then it queries data from the 3rd party application, determines the deltas and then inserts the data where required. Specifically here we are calling Oracle Sales Cloud using SOAP/WebServices and the 3rd party application is being communicated to using the REST API, for Oracle Sales Cloud one would use standard JAX-WS WebService calls and for REST one would use the JAX-RS api and perhap the Jackson api for managing JSON objects.. This is a very common use case and one which specifically lends itself to using the Oracle Java Cloud Service as the ideal application server where to host the mediator between the two applications.  Techniques Used Using JWT Token in Sales Cloud Integrating with the Oracle Java Cloud Service Retrieving Data from Oracle Sales cloud using WebServices General Resources The above is just a small set of techniques and use-cases which are used today. There are plenty of other sources of documentation and resources available on the internet but to get you started here are a few of my favourite places  Sales Cloud General Documentation Sales Cloud Customize Tab is useful for general customization of Sales Cloud Sales Cloud Integration Tab focuses on the 3rd party integration techniques  Official Oracle Fusion Developer Relations Blog Official Oracle Fusion Developer Relations YouTube Channel Enjoy integrating! 

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• Using Transaction Logging to Recover Post-Archived Essbase data

  - by Keith Rosenthal

  Data recovery is typically performed by restoring data from an archive.  Data added or removed since the last archive took place can also be recovered by enabling transaction logging in Essbase.  Transaction logging works by writing transactions to a log store.  The information in the log store can then be recovered by replaying the log store entries in sequence since the last archive took place.  The following information is recorded within a transaction log entry: Sequence ID Username Start Time End Time Request Type A request type can be one of the following categories: Calculations, including the default calculation as well as both server and client side calculations Data loads, including data imports as well as data loaded using a load rule Data clears as well as outline resets Locking and sending data from SmartView and the Spreadsheet Add-In.  Changes from Planning web forms are also tracked since a lock and send operation occurs during this process. You can use the Display Transactions command in the EAS console or the query database MAXL command to view the transaction log entries. Enabling Transaction Logging Transaction logging can be enabled at the Essbase server, application or database level by adding the TRANSACTIONLOGLOCATION essbase.cfg setting.  The following is the TRANSACTIONLOGLOCATION syntax: TRANSACTIONLOGLOCATION [appname [dbname]] LOGLOCATION NATIVE ENABLE | DISABLE Note that you can have multiple TRANSACTIONLOGLOCATION entries in the essbase.cfg file.  For example: TRANSACTIONLOGLOCATION Hyperion/trlog NATIVE ENABLE TRANSACTIONLOGLOCATION Sample Hyperion/trlog NATIVE DISABLE The first statement will enable transaction logging for all Essbase applications, and the second statement will disable transaction logging for the Sample application.  As a result, transaction logging will be enabled for all applications except the Sample application. A location on a physical disk other than the disk where ARBORPATH or the disk files reside is recommended to optimize overall Essbase performance. Configuring Transaction Log Replay Although transaction log entries are stored based on the LOGLOCATION parameter of the TRANSACTIONLOGLOCATION essbase.cfg setting, copies of data load and rules files are stored in the ARBORPATH/app/appname/dbname/Replay directory to optimize the performance of replaying logged transactions.  The default is to archive client data loads, but this configuration setting can be used to archive server data loads (including SQL server data loads) or both client and server data loads. To change the type of data to be archived, add the TRANSACTIONLOGDATALOADARCHIVE configuration setting to the essbase.cfg file.  Note that you can have multiple TRANSACTIONLOGDATALOADARCHIVE entries in the essbase.cfg file to adjust settings for individual applications and databases. Replaying the Transaction Log and Transaction Log Security Considerations To replay the transactions, use either the Replay Transactions command in the EAS console or the alter database MAXL command using the replay transactions grammar.  Transactions can be replayed either after a specified log time or using a range of transaction sequence IDs. The default when replaying transactions is to use the security settings of the user who originally performed the transaction.  However, if that user no longer exists or that user's username was changed, the replay operation will fail. Instead of using the default security setting, add the REPLAYSECURITYOPTION essbase.cfg setting to use the security settings of the administrator who performs the replay operation.  REPLAYSECURITYOPTION 2 will explicitly use the security settings of the administrator performing the replay operation.  REPLAYSECURITYOPTION 3 will use the administrator security settings if the original user’s security settings cannot be used. Removing Transaction Logs and Archived Replay Data Load and Rules Files Transaction logs and archived replay data load and rules files are not automatically removed and are only removed manually.  Since these files can consume a considerable amount of space, the files should be removed on a periodic basis. The transaction logs should be removed one database at a time instead of all databases simultaneously.  The data load and rules files associated with the replayed transactions should be removed in chronological order from earliest to latest.  In addition, do not remove any data load and rules files with a timestamp later than the timestamp of the most recent archive file. Partitioned Database Considerations For partitioned databases, partition commands such as synchronization commands cannot be replayed.  When recovering data, the partition changes must be replayed manually and logged transactions must be replayed in the correct chronological order. If the partitioned database includes any @XREF commands in the calc script, the logged transactions must be selectively replayed in the correct chronological order between the source and target databases. References For additional information, please see the Oracle EPM System Backup and Recovery Guide.  For EPM 11.1.2.2, the link is http://docs.oracle.com/cd/E17236_01/epm.1112/epm_backup_recovery_1112200.pdf

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• Developing Schema Compare for Oracle (Part 5): Query Snapshots

  - by Simon Cooper

  If you've emailed us about a bug you've encountered with the EAP or beta versions of Schema Compare for Oracle, we probably asked you to send us a query snapshot of your databases. Here, I explain what a query snapshot is, and how it helps us fix your bug. Problem 1: Debugging users' bug reports When we started the Schema Compare project, we knew we were going to get problems with users' databases - configurations we hadn't considered, features that weren't installed, unicode issues, wierd dependencies... With SQL Compare, users are generally happy to send us a database backup that we can restore using a single RESTORE DATABASE command on our test servers and immediately reproduce the problem. Oracle, on the other hand, would be a lot more tricky. As Oracle generally has a 1-to-1 mapping between instances and databases, any databases users sent would have to be restored to their own instance. Furthermore, the number of steps required to get a properly working database, and the size of most oracle databases, made it infeasible to ask every customer who came across a bug during our beta program to send us their databases. We also knew that there would be lots of issues with data security that would make it hard to get backups. So we needed an easier way to be able to debug customers issues and sort out what strange schema data Oracle was returning. Problem 2: Test execution time Another issue we knew we would have to solve was the execution time of the tests we would produce for the Schema Compare engine. Our initial prototype showed that querying the data dictionary for schema information was going to be slow (at least 15 seconds per database), and this is generally proportional to the size of the database. If you're running thousands of tests on the same databases, each one registering separate schemas, not only would the tests would take hours and hours to run, but the test servers would be hammered senseless. The solution To solve these, we needed to be able to populate the schema of a database without actually connecting to it. Well, the IDataReader interface is the primary way we read data from an Oracle server. The data dictionary queries we use return their data in terms of simple strings and numbers, which we then process and reconstruct into an object model, and the results of these queries are identical for identical schemas. So, we can record the raw results of the queries once, and then replay these results to construct the same object model as many times as required without needing to actually connect to the original database. This is what query snapshots do. They are binary files containing the raw unprocessed data we get back from the oracle server for all the queries we run on the data dictionary to get schema information. The core of the query snapshot generation takes the results of the IDataReader we get from running queries on Oracle, and passes the row data to a BinaryWriter that writes it straight to a file. The query snapshot can then be replayed to create the same object model; when the results of a specific query is needed by the population code, we can simply read the binary data stored in the file on disk and present it through an IDataReader wrapper. This is far faster than querying the server over the network, and allows us to run tests in a reasonable time. They also allow us to easily debug a customers problem; using a simple snapshot generation program, users can generate a query snapshot that could be sent along with a bug report that we can immediately replay on our machines to let us debug the issue, rather than having to obtain database backups and restore databases to test systems. There are also far fewer problems with data security; query snapshots only contain schema information, which is generally less sensitive than table data. Query snapshots implementation However, actually implementing such a feature did have a couple of 'gotchas' to it. My second blog post detailed the development of the dependencies algorithm we use to ensure we get all the dependencies in the database, and that algorithm uses data from both databases to find all the needed objects - what database you're comparing to affects what objects get populated from both databases. We get information on these additional objects using an appropriate WHERE clause on all the population queries. So, in order to accurately replay the results of querying the live database, the query snapshot needs to be a snapshot of a comparison of two databases, not just populating a single database. Furthermore, although the code population queries (eg querying all_tab_cols to get column information) can simply be passed straight from the IDataReader to the BinaryWriter, we need to hook into and run the live dependencies algorithm while we're creating the snapshot to ensure we get the same WHERE clauses, and the same query results, as if we were populating straight from a live system. We also need to store the results of the dependencies queries themselves, as the resulting dependency graph is stored within the OracleDatabase object that is produced, and is later used to help order actions in synchronization scripts. This is significantly helped by the dependencies algorithm being a deterministic algorithm - given the same input, it will always return the same output. Therefore, when we're replaying a query snapshot, and processing dependency information, we simply have to return the results of the queries in the order we got them from the live database, rather than trying to calculate the contents of all_dependencies on the fly. Query snapshots are a significant feature in Schema Compare that really helps us to debug problems with the tool, as well as making our testers happier. Although not really user-visible, they are very useful to the development team to help us fix bugs in the product much faster than we otherwise would be able to.

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• Subterranean IL: The ThreadLocal type

  - by Simon Cooper

  I came across ThreadLocal<T> while I was researching ConcurrentBag. To look at it, it doesn't really make much sense. What's all those extra Cn classes doing in there? Why is there a GenericHolder<T,U,V,W> class? What's going on? However, digging deeper, it's a rather ingenious solution to a tricky problem. Thread statics Declaring that a variable is thread static, that is, values assigned and read from the field is specific to the thread doing the reading, is quite easy in .NET: [ThreadStatic] private static string s_ThreadStaticField; ThreadStaticAttribute is not a pseudo-custom attribute; it is compiled as a normal attribute, but the CLR has in-built magic, activated by that attribute, to redirect accesses to the field based on the executing thread's identity. TheadStaticAttribute provides a simple solution when you want to use a single field as thread-static. What if you want to create an arbitary number of thread static variables at runtime? Thread-static fields can only be declared, and are fixed, at compile time. Prior to .NET 4, you only had one solution - thread local data slots. This is a lesser-known function of Thread that has existed since .NET 1.1: LocalDataStoreSlot threadSlot = Thread.AllocateNamedDataSlot("slot1"); string value = "foo"; Thread.SetData(threadSlot, value); string gettedValue = (string)Thread.GetData(threadSlot); Each instance of LocalStoreDataSlot mediates access to a single slot, and each slot acts like a separate thread-static field. As you can see, using thread data slots is quite cumbersome. You need to keep track of LocalDataStoreSlot objects, it's not obvious how instances of LocalDataStoreSlot correspond to individual thread-static variables, and it's not type safe. It's also relatively slow and complicated; the internal implementation consists of a whole series of classes hanging off a single thread-static field in Thread itself, using various arrays, lists, and locks for synchronization. ThreadLocal<T> is far simpler and easier to use. ThreadLocal ThreadLocal provides an abstraction around thread-static fields that allows it to be used just like any other class; it can be used as a replacement for a thread-static field, it can be used in a List<ThreadLocal<T>>, you can create as many as you need at runtime. So what does it do? It can't just have an instance-specific thread-static field, because thread-static fields have to be declared as static, and so shared between all instances of the declaring type. There's something else going on here. The values stored in instances of ThreadLocal<T> are stored in instantiations of the GenericHolder<T,U,V,W> class, which contains a single ThreadStatic field (s_value) to store the actual value. This class is then instantiated with various combinations of the Cn types for generic arguments. In .NET, each separate instantiation of a generic type has its own static state. For example, GenericHolder<int,C0,C1,C2> has a completely separate s_value field to GenericHolder<int,C1,C14,C1>. This feature is (ab)used by ThreadLocal to emulate instance thread-static fields. Every time an instance of ThreadLocal is constructed, it is assigned a unique number from the static s_currentTypeId field using Interlocked.Increment, in the FindNextTypeIndex method. The hexadecimal representation of that number then defines the specific Cn types that instantiates the GenericHolder class. That instantiation is therefore 'owned' by that instance of ThreadLocal. This gives each instance of ThreadLocal its own ThreadStatic field through a specific unique instantiation of the GenericHolder class. Although GenericHolder has four type variables, the first one is always instantiated to the type stored in the ThreadLocal<T>. This gives three free type variables, each of which can be instantiated to one of 16 types (C0 to C15). This puts an upper limit of 4096 (163) on the number of ThreadLocal<T> instances that can be created for each value of T. That is, there can be a maximum of 4096 instances of ThreadLocal<string>, and separately a maximum of 4096 instances of ThreadLocal<object>, etc. However, there is an upper limit of 16384 enforced on the total number of ThreadLocal instances in the AppDomain. This is to stop too much memory being used by thousands of instantiations of GenericHolder<T,U,V,W>, as once a type is loaded into an AppDomain it cannot be unloaded, and will continue to sit there taking up memory until the AppDomain is unloaded. The total number of ThreadLocal instances created is tracked by the ThreadLocalGlobalCounter class. So what happens when either limit is reached? Firstly, to try and stop this limit being reached, it recycles GenericHolder type indexes of ThreadLocal instances that get disposed using the s_availableIndices concurrent stack. This allows GenericHolder instantiations of disposed ThreadLocal instances to be re-used. But if there aren't any available instantiations, then ThreadLocal falls back on a standard thread local slot using TLSHolder. This makes it very important to dispose of your ThreadLocal instances if you'll be using lots of them, so the type instantiations can be recycled. The previous way of creating arbitary thread-static variables, thread data slots, was slow, clunky, and hard to use. In comparison, ThreadLocal can be used just like any other type, and each instance appears from the outside to be a non-static thread-static variable. It does this by using the CLR type system to assign each instance of ThreadLocal its own instantiated type containing a thread-static field, and so delegating a lot of the bookkeeping that thread data slots had to do to the CLR type system itself! That's a very clever use of the CLR type system.

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• Inside BackgroundWorker

  - by João Angelo

  The BackgroundWorker is a reusable component that can be used in different contexts, but sometimes with unexpected results. If you are like me, you have mostly used background workers while doing Windows Forms development due to the flexibility they offer for running a background task. They support cancellation and give events that signal progress updates and task completion. When used in Windows Forms, these events (ProgressChanged and RunWorkerCompleted) get executed back on the UI thread where you can freely access your form controls. However, the logic of the progress changed and worker completed events being invoked in the thread that started the background worker is not something you get directly from the BackgroundWorker, but instead from the fact that you are running in the context of Windows Forms. Take the following example that illustrates the use of a worker in three different scenarios: – Console Application or Windows Service; – Windows Forms; – WPF. using System; using System.ComponentModel; using System.Threading; using System.Windows.Forms; using System.Windows.Threading; class Program { static AutoResetEvent Synch = new AutoResetEvent(false); static void Main() { var bw1 = new BackgroundWorker(); var bw2 = new BackgroundWorker(); var bw3 = new BackgroundWorker(); Console.WriteLine("DEFAULT"); var unspecializedThread = new Thread(() => { OutputCaller(1); SynchronizationContext.SetSynchronizationContext( new SynchronizationContext()); bw1.DoWork += (sender, e) => OutputWork(1); bw1.RunWorkerCompleted += (sender, e) => OutputCompleted(1); // Uses default SynchronizationContext bw1.RunWorkerAsync(); }); unspecializedThread.IsBackground = true; unspecializedThread.Start(); Synch.WaitOne(); Console.WriteLine(); Console.WriteLine("WINDOWS FORMS"); var windowsFormsThread = new Thread(() => { OutputCaller(2); SynchronizationContext.SetSynchronizationContext( new WindowsFormsSynchronizationContext()); bw2.DoWork += (sender, e) => OutputWork(2); bw2.RunWorkerCompleted += (sender, e) => OutputCompleted(2); // Uses WindowsFormsSynchronizationContext bw2.RunWorkerAsync(); Application.Run(); }); windowsFormsThread.IsBackground = true; windowsFormsThread.SetApartmentState(ApartmentState.STA); windowsFormsThread.Start(); Synch.WaitOne(); Console.WriteLine(); Console.WriteLine("WPF"); var wpfThread = new Thread(() => { OutputCaller(3); SynchronizationContext.SetSynchronizationContext( new DispatcherSynchronizationContext()); bw3.DoWork += (sender, e) => OutputWork(3); bw3.RunWorkerCompleted += (sender, e) => OutputCompleted(3); // Uses DispatcherSynchronizationContext bw3.RunWorkerAsync(); Dispatcher.Run(); }); wpfThread.IsBackground = true; wpfThread.SetApartmentState(ApartmentState.STA); wpfThread.Start(); Synch.WaitOne(); } static void OutputCaller(int workerId) { Console.WriteLine( "bw{0}.{1} | Thread: {2} | IsThreadPool: {3}", workerId, "RunWorkerAsync".PadRight(18), Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread); } static void OutputWork(int workerId) { Console.WriteLine( "bw{0}.{1} | Thread: {2} | IsThreadPool: {3}", workerId, "DoWork".PadRight(18), Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread); } static void OutputCompleted(int workerId) { Console.WriteLine( "bw{0}.{1} | Thread: {2} | IsThreadPool: {3}", workerId, "RunWorkerCompleted".PadRight(18), Thread.CurrentThread.ManagedThreadId, Thread.CurrentThread.IsThreadPoolThread); Synch.Set(); } } Output: //DEFAULT //bw1.RunWorkerAsync | Thread: 3 | IsThreadPool: False //bw1.DoWork | Thread: 4 | IsThreadPool: True //bw1.RunWorkerCompleted | Thread: 5 | IsThreadPool: True //WINDOWS FORMS //bw2.RunWorkerAsync | Thread: 6 | IsThreadPool: False //bw2.DoWork | Thread: 5 | IsThreadPool: True //bw2.RunWorkerCompleted | Thread: 6 | IsThreadPool: False //WPF //bw3.RunWorkerAsync | Thread: 7 | IsThreadPool: False //bw3.DoWork | Thread: 5 | IsThreadPool: True //bw3.RunWorkerCompleted | Thread: 7 | IsThreadPool: False As you can see the output between the first and remaining scenarios is somewhat different. While in Windows Forms and WPF the worker completed event runs on the thread that called RunWorkerAsync, in the first scenario the same event runs on any thread available in the thread pool. Another scenario where you can get the first behavior, even when on Windows Forms or WPF, is if you chain the creation of background workers, that is, you create a second worker in the DoWork event handler of an already running worker. Since the DoWork executes in a thread from the pool the second worker will use the default synchronization context and the completed event will not run in the UI thread.

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• Performance triage

  - by Dave

  Folks often ask me how to approach a suspected performance issue. My personal strategy is informed by the fact that I work on concurrency issues. (When you have a hammer everything looks like a nail, but I'll try to keep this general). A good starting point is to ask yourself if the observed performance matches your expectations. Expectations might be derived from known system performance limits, prototypes, and other software or environments that are comparable to your particular system-under-test. Some simple comparisons and microbenchmarks can be useful at this stage. It's also useful to write some very simple programs to validate some of the reported or expected system limits. Can that disk controller really tolerate and sustain 500 reads per second? To reduce the number of confounding factors it's better to try to answer that question with a very simple targeted program. And finally, nothing beats having familiarity with the technologies that underlying your particular layer. On the topic of confounding factors, as our technology stacks become deeper and less transparent, we often find our own technology working against us in some unexpected way to choke performance rather than simply running into some fundamental system limit. A good example is the warm-up time needed by just-in-time compilers in Java Virtual Machines. I won't delve too far into that particular hole except to say that it's rare to find good benchmarks and methodology for java code. Another example is power management on x86. Power management is great, but it can take a while for the CPUs to throttle up from low(er) frequencies to full throttle. And while I love "turbo" mode, it makes benchmarking applications with multiple threads a chore as you have to remember to turn it off and then back on otherwise short single-threaded runs may look abnormally fast compared to runs with higher thread counts. In general for performance characterization I disable turbo mode and fix the power governor at "performance" state. Another source of complexity is the scheduler, which I've discussed in prior blog entries. Lets say I have a running application and I want to better understand its behavior and performance. We'll presume it's warmed up, is under load, and is an execution mode representative of what we think the norm would be. It should be in steady-state, if a steady-state mode even exists. On Solaris the very first thing I'll do is take a set of "pstack" samples. Pstack briefly stops the process and walks each of the stacks, reporting symbolic information (if available) for each frame. For Java, pstack has been augmented to understand java frames, and even report inlining. A few pstack samples can provide powerful insight into what's actually going on inside the program. You'll be able to see calling patterns, which threads are blocked on what system calls or synchronization constructs, memory allocation, etc. If your code is CPU-bound then you'll get a good sense where the cycles are being spent. (I should caution that normal C/C++ inlining can diffuse an otherwise "hot" method into other methods. This is a rare instance where pstack sampling might not immediately point to the key problem). At this point you'll need to reconcile what you're seeing with pstack and your mental model of what you think the program should be doing. They're often rather different. And generally if there's a key performance issue, you'll spot it with a moderate number of samples. I'll also use OS-level observability tools to lock for the existence of bottlenecks where threads contend for locks; other situations where threads are blocked; and the distribution of threads over the system. On Solaris some good tools are mpstat and too a lesser degree, vmstat. Try running "mpstat -a 5" in one window while the application program runs concurrently. One key measure is the voluntary context switch rate "vctx" or "csw" which reflects threads descheduling themselves. It's also good to look at the user; system; and idle CPU percentages. This can give a broad but useful understanding if your threads are mostly parked or mostly running. For instance if your program makes heavy use of malloc/free, then it might be the case you're contending on the central malloc lock in the default allocator. In that case you'd see malloc calling lock in the stack traces, observe a high csw/vctx rate as threads block for the malloc lock, and your "usr" time would be less than expected. Solaris dtrace is a wonderful and invaluable performance tool as well, but in a sense you have to frame and articulate a meaningful and specific question to get a useful answer, so I tend not to use it for first-order screening of problems. It's also most effective for OS and software-level performance issues as opposed to HW-level issues. For that reason I recommend mpstat & pstack as my the 1st step in performance triage. If some other OS-level issue is evident then it's good to switch to dtrace to drill more deeply into the problem. Only after I've ruled out OS-level issues do I switch to using hardware performance counters to look for architectural impediments.

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• Developing Schema Compare for Oracle (Part 4): Script Configuration

  - by Simon Cooper

  If you've had a chance to play around with the Schema Compare for Oracle beta, you may have come across this screen in the synchronization wizard: This screen is one of the few screens that, along with the project configuration form, doesn't come from SQL Compare. This screen was designed to solve a couple of issues that, although aren't specific to Oracle, are much more of a problem than on SQL Server: Datatype conversions and NOT NULL columns. 1. Datatype conversions SQL Server is generally quite forgiving when it comes to datatype conversions using ALTER TABLE. For example, you can convert from a VARCHAR to INT using ALTER TABLE as long as all the character values are parsable as integers. Oracle, on the other hand, only allows ALTER TABLE conversions that don't change the internal data format. Essentially, every change that requires an actual datatype conversion has to be done using a rebuild with a conversion function. That's OK, as we can simply hard-code the various conversion functions for the valid datatype conversions and insert those into the rebuild SELECT list. However, as there always is with Oracle, there's a catch. Have a look at the NUMTODSINTERVAL function. As well as specifying the value (or column) to convert, you have to specify an interval_unit, which tells oracle how to interpret the input number. We can't hardcode a default for this parameter, as it is entirely dependent on the user's data context! So, in order to convert NUMBER to INTERVAL DAY TO SECOND/INTERVAL YEAR TO MONTH, we need to have feedback from the user as to what to put in this parameter while we're generating the sync script - this requires a new step in the engine action/script generation to insert these values into the script, as well as new UI to allow the user to specify these values in a sensible fashion. In implementing the engine and UI infrastructure to allow this it made much more sense to implement it for any rebuild datatype conversion, not just NUMBER to INTERVALs. For conversions which we can do, we pre-fill the 'value' box with the appropriate function from the documentation. The user can also type in arbitary SQL expressions, which allows the user to specify optional format parameters for the relevant conversion functions, or indeed call their own functions to convert between values that don't have a built-in conversion defined. As the value gets inserted as-is into the rebuild SELECT list, any expression that is valid in that context can be specified as the conversion value. 2. NOT NULL columns Another problem that is solved by the new step in the sync wizard is adding a NOT NULL column to a table. If the table contains data (as most database tables do), you can't just add a NOT NULL column, as Oracle doesn't know what value to put in the new column for existing rows - the DDL statement will fail. There are actually 3 separate scenarios for this problem that have separate solutions within the engine: Adding a NOT NULL column to a table without a rebuild Here, the workaround is to add a column default with an appropriate value to the column you're adding: ALTER TABLE tbl1 ADD newcol NUMBER DEFAULT <value> NOT NULL; Note, however, there is something to bear in mind about this solution; once specified on a column, a default cannot be removed. To 'remove' a default from a column you change it to have a default of NULL, hence there's code in the engine to treat a NULL default the same as no default at all. Adding a NOT NULL column to a table, where a separate change forced a table rebuild Fortunately, in this case, a column default is not required - we can simply insert the default value into the rebuild SELECT clause. Changing an existing NULL to a NOT NULL column To implement this, we run an UPDATE command before the ALTER TABLE to change all the NULLs in the column to the required default value. For all three, we need some way of allowing the user to specify a default value to use instead of NULL; as this is essentially the same problem as datatype conversion (inserting values into the sync script), we can re-use the UI and engine implementation of datatype conversion values. We also provide the option to alter the new column to allow NULLs, or to ignore the problem completely. Note that there is the same (long-running) problem in SQL Compare, but it is much more of an issue in Oracle as you cannot easily roll back executed DDL statements if the script fails at some point during execution. Furthermore, the engine of SQL Compare is far less conducive to inserting user-supplied values into the generated script. As we're writing the Schema Compare engine from scratch, we used what we learnt from the SQL Compare engine and designed it to be far more modular, which makes inserting procedures like this much easier.

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• How can I implement a database TableView like thing in C++?

  - by Industrial-antidepressant

  How can I implement a TableView like thing in C++? I want to emulating a tiny relation database like thing in C++. I have data tables, and I want to transform it somehow, so I need a TableView like class. I want filtering, sorting, freely add and remove items and transforming (ex. view as UPPERCASE and so on). The whole thing is inside a GUI application, so datatables and views are attached to a GUI (or HTML or something). So how can I identify an item in the view? How can I signal it when the table is changed? Is there some design pattern for this? Here is a simple table, and a simple data item: #include <string> #include <boost/multi_index_container.hpp> #include <boost/multi_index/member.hpp> #include <boost/multi_index/ordered_index.hpp> #include <boost/multi_index/random_access_index.hpp> using boost::multi_index_container; using namespace boost::multi_index; struct Data { Data() {} int id; std::string name; }; struct row{}; struct id{}; struct name{}; typedef boost::multi_index_container< Data, indexed_by< random_access<tag<row> >, ordered_unique<tag<id>, member<Data, int, &Data::id> >, ordered_unique<tag<name>, member<Data, std::string, &Data::name> > > > TDataTable; class DataTable { public: typedef Data item_type; typedef TDataTable::value_type value_type; typedef TDataTable::const_reference const_reference; typedef TDataTable::index<row>::type TRowIndex; typedef TDataTable::index<id>::type TIdIndex; typedef TDataTable::index<name>::type TNameIndex; typedef TRowIndex::iterator iterator; DataTable() : row_index(rule_table.get<row>()), id_index(rule_table.get<id>()), name_index(rule_table.get<name>()), row_index_writeable(rule_table.get<row>()) { } TDataTable::const_reference operator[](TDataTable::size_type n) const { return rule_table[n]; } std::pair<iterator,bool> push_back(const value_type& x) { return row_index_writeable.push_back(x); } iterator erase(iterator position) { return row_index_writeable.erase(position); } bool replace(iterator position,const value_type& x) { return row_index_writeable.replace(position, x); } template<typename InputIterator> void rearrange(InputIterator first) { return row_index_writeable.rearrange(first); } void print_table() const; unsigned size() const { return row_index.size(); } TDataTable rule_table; const TRowIndex& row_index; const TIdIndex& id_index; const TNameIndex& name_index; private: TRowIndex& row_index_writeable; }; class DataTableView { DataTableView(const DataTable& source_table) {} // How can I implement this? // I want filtering, sorting, signaling upper GUI layer, and sorting, and ... }; int main() { Data data1; data1.id = 1; data1.name = "name1"; Data data2; data2.id = 2; data2.name = "name2"; DataTable table; table.push_back(data1); DataTable::iterator it1 = table.row_index.iterator_to(table[0]); table.erase(it1); table.push_back(data1); Data new_data(table[0]); new_data.name = "new_name"; table.replace(table.row_index.iterator_to(table[0]), new_data); for (unsigned i = 0; i < table.size(); ++i) std::cout << table[i].name << std::endl; #if 0 // using scenarios: DataTableView table_view(table); table_view.fill_from_source(); // synchronization with source table_view.remove(data_item1); // remove item from view table_view.add(data_item2); // add item from source table table_view.filter(filterfunc); // filtering table_view.sort(sortfunc); // sorting // modifying from source_able, hot to signal the table_view? // FYI: Table view is atteched to a GUI item table.erase(data); table.replace(data); #endif return 0; }

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• NEC uPD720200 USB 3.0 not working on Ubuntu 12.04

  - by Jagged

  I've recently installed Ubuntu 12.04 64-bit on a HP Envy 15 1104tx. Most stuff appears to be working fine with the exception of the two USB3 ports (USB2 port works fine). I've read a lot of articles but so far have not been able to find a solution. I've tried adding 'pci=nomsi' to '/etc/default/grub' but this made no difference. Some articles suggest booting into Windows and upgrading the firmware on the uPD720200. Any body had any experience of this? Is there a way I can checked the firmware version of the NEC uPD720200 in Linux to see if there is an update available? Any help appreciated. uname -a: Linux HP-ENVY-15-1104tx 3.2.0-26-generic #41-Ubuntu SMP Thu Jun 14 17:49:24 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux lshw: hp-envy-15-1104tx description: Notebook product: HP ENVY 15 Notebook PC (WF591PA#ABG) vendor: Hewlett-Packard version: 0492110000241910001420000 serial: CNF0301C79 width: 64 bits capabilities: smbios-2.6 dmi-2.6 vsyscall32 configuration: boot=normal chassis=notebook family=103C_5335KV sku=WF591PA#ABG uuid=434E4630-3330-3143-3739-60EB6906688F *-core description: Motherboard product: 1522 vendor: Hewlett-Packard physical id: 0 version: 36.35 serial: CNF0301C79 slot: Base Board Chassis Location *-firmware description: BIOS vendor: Hewlett-Packard physical id: 0 version: F.2B date: 10/12/2010 size: 1MiB capacity: 1472KiB capabilities: pci upgrade shadowing cdboot bootselect edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb biosbootspecification *-memory description: System Memory physical id: 13 slot: System board or motherboard size: 16GiB *-bank:0 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 0 serial: E13C4316 slot: Bottom size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:1 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 1 serial: E03C3E16 slot: Bottom size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:2 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 2 serial: 672279CC slot: On Board size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:3 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: 9905428-043.A00LF physical id: 3 serial: 652286CC slot: On Board size: 4GiB width: 64 bits clock: 1333MHz (0.8ns) *-cpu description: CPU product: Intel(R) Core(TM) i7 CPU Q 820 @ 1.73GHz vendor: Intel Corp. physical id: 1d bus info: cpu@0 version: Intel(R) Core(TM) i7 CPU Q 820 @ 1.73GHz slot: CPU size: 1199MHz capacity: 1199MHz width: 64 bits clock: 1066MHz capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid cpufreq configuration: cores=4 enabledcores=4 threads=8 *-cache:0 description: L3 cache physical id: 1e slot: L3 Cache size: 8MiB capacity: 8MiB capabilities: synchronous internal write-through unified *-cache:1 description: L2 cache physical id: 20 slot: L2 Cache size: 256KiB capacity: 256KiB capabilities: synchronous internal write-through unified *-cache:2 description: L1 cache physical id: 21 slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through instruction *-cache description: L1 cache physical id: 1f slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through data *-pci:0 description: Host bridge product: Core Processor DMI vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 11 width: 32 bits clock: 33MHz *-pci:0 description: PCI bridge product: Core Processor PCI Express Root Port 1 vendor: Intel Corporation physical id: 3 bus info: pci@0000:00:03.0 version: 11 width: 32 bits clock: 33MHz capabilities: pci msi pciexpress pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 ioport:4000(size=4096) memory:d4100000-d41fffff ioport:c0000000(size=268435456) *-display description: VGA compatible controller product: Broadway PRO [Mobility Radeon HD 5800 Series] vendor: Hynix Semiconductor (Hyundai Electronics) physical id: 0 bus info: pci@0000:01:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: pm pciexpress msi vga_controller bus_master cap_list rom configuration: driver=fglrx_pci latency=0 resources: irq:58 memory:c0000000-cfffffff memory:d4100000-d411ffff ioport:4000(size=256) memory:d4140000-d415ffff *-multimedia description: Audio device product: Juniper HDMI Audio [Radeon HD 5700 Series] vendor: Hynix Semiconductor (Hyundai Electronics) physical id: 0.1 bus info: pci@0000:01:00.1 version: 00 width: 64 bits clock: 33MHz capabilities: pm pciexpress msi bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:56 memory:d4120000-d4123fff *-pci:1 description: PCI bridge product: Core Processor PCI Express Root Port 3 vendor: Intel Corporation physical id: 5 bus info: pci@0000:00:05.0 version: 11 width: 32 bits clock: 33MHz capabilities: pci msi pciexpress pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 memory:d4000000-d40fffff *-usb description: USB controller product: uPD720200 USB 3.0 Host Controller vendor: NEC Corporation physical id: 0 bus info: pci@0000:02:00.0 version: 03 width: 64 bits clock: 33MHz capabilities: pm msi msix pciexpress xhci bus_master cap_list configuration: driver=xhci_hcd latency=0 resources: irq:16 memory:d4000000-d4001fff *-generic:0 UNCLAIMED description: System peripheral product: Core Processor System Management Registers vendor: Intel Corporation physical id: 8 bus info: pci@0000:00:08.0 version: 11 width: 32 bits clock: 33MHz capabilities: pciexpress cap_list configuration: latency=0 *-generic:1 UNCLAIMED description: System peripheral product: Core Processor Semaphore and Scratchpad Registers vendor: Intel Corporation physical id: 8.1 bus info: pci@0000:00:08.1 version: 11 width: 32 bits clock: 33MHz capabilities: pciexpress cap_list configuration: latency=0 *-generic:2 UNCLAIMED description: System peripheral product: Core Processor System Control and Status Registers vendor: Intel Corporation physical id: 8.2 bus info: pci@0000:00:08.2 version: 11 width: 32 bits clock: 33MHz capabilities: pciexpress cap_list configuration: latency=0 *-generic:3 UNCLAIMED description: System peripheral product: Core Processor Miscellaneous Registers vendor: Intel Corporation physical id: 8.3 bus info: pci@0000:00:08.3 version: 11 width: 32 bits clock: 33MHz configuration: latency=0 *-generic:4 UNCLAIMED description: System peripheral product: Core Processor QPI Link vendor: Intel Corporation physical id: 10 bus info: pci@0000:00:10.0 version: 11 width: 32 bits clock: 33MHz configuration: latency=0 *-generic:5 UNCLAIMED description: System peripheral product: Core Processor QPI Routing and Protocol Registers vendor: Intel Corporation physical id: 10.1 bus info: pci@0000:00:10.1 version: 11 width: 32 bits clock: 33MHz configuration: latency=0 *-multimedia description: Audio device product: 5 Series/3400 Series Chipset High Definition Audio vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 05 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:55 memory:d4200000-d4203fff *-pci:2 description: PCI bridge product: 5 Series/3400 Series Chipset PCI Express Root Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: 05 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:17 ioport:3000(size=4096) memory:d3000000-d3ffffff ioport:d0000000(size=16777216) *-network description: Wireless interface product: Centrino Advanced-N 6200 vendor: Intel Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan0 version: 35 serial: 00:27:10:40:e4:68 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=iwlwifi driverversion=3.2.0-26-generic firmware=9.221.4.1 build 25532 latency=0 link=no multicast=yes wireless=IEEE 802.11abgn resources: irq:54 memory:d3000000-d3001fff *-pci:3 description: PCI bridge product: 5 Series/3400 Series Chipset PCI Express Root Port 2 vendor: Intel Corporation physical id: 1c.1 bus info: pci@0000:00:1c.1 version: 05 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 ioport:2000(size=4096) memory:d2000000-d2ffffff ioport:d1000000(size=16777216) *-network description: Ethernet interface product: AR8131 Gigabit Ethernet vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:04:00.0 logical name: eth0 version: c0 serial: 60:eb:69:06:68:8f size: 1Gbit/s capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vpd bus_master cap_list ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=atl1c driverversion=1.0.1.0-NAPI duplex=full firmware=N/A ip=10.161.0.147 latency=0 link=yes multicast=yes port=twisted pair speed=1Gbit/s resources: irq:57 memory:d2000000-d203ffff ioport:2000(size=128) *-usb description: USB controller product: 5 Series/3400 Series Chipset USB2 Enhanced Host Controller vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 05 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:20 memory:d4205800-d4205bff *-pci:4 description: PCI bridge product: 82801 Mobile PCI Bridge vendor: Intel Corporation physical id: 1e bus info: pci@0000:00:1e.0 version: a5 width: 32 bits clock: 33MHz capabilities: pci subtractive_decode bus_master cap_list *-isa description: ISA bridge product: Mobile 5 Series Chipset LPC Interface Controller vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 05 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: latency=0 *-storage description: RAID bus controller product: 82801 Mobile SATA Controller [RAID mode] vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 logical name: scsi0 version: 05 width: 32 bits clock: 66MHz capabilities: storage msi pm bus_master cap_list emulated configuration: driver=ahci latency=0 resources: irq:45 ioport:5048(size=8) ioport:5054(size=4) ioport:5040(size=8) ioport:5050(size=4) ioport:5020(size=32) memory:d4205000-d42057ff *-disk description: ATA Disk product: OCZ-VERTEX3 physical id: 0.0.0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: 2.15 serial: OCZ-0350P6H316X5KUQE size: 223GiB (240GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=000592dd *-volume:0 description: EXT4 volume vendor: Linux physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 logical name: / version: 1.0 serial: e741f18c-cfc5-4bce-b1e7-f80e517a3a22 size: 207GiB capacity: 207GiB capabilities: primary bootable journaled extended_attributes large_files huge_files dir_nlink recover extents ext4 ext2 initialized configuration: created=2012-06-15 06:49:27 filesystem=ext4 lastmountpoint=/ modified=2012-06-14 21:23:42 mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,user_xattr,barrier=1,data=ordered mounted=2012-07-10 16:18:20 state=mounted *-volume:1 description: Extended partition physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 size: 15GiB capacity: 15GiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume description: Linux swap / Solaris partition physical id: 5 logical name: /dev/sda5 capacity: 15GiB capabilities: nofs *-serial UNCLAIMED description: SMBus product: 5 Series/3400 Series Chipset SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 05 width: 64 bits clock: 33MHz configuration: latency=0 resources: memory:d4205c00-d4205cff ioport:5000(size=32) *-pci:1 description: Host bridge product: Core Processor QuickPath Architecture Generic Non-Core Registers vendor: Intel Corporation physical id: 101 bus info: pci@0000:ff:00.0 version: 04 width: 32 bits clock: 33MHz *-pci:2 description: Host bridge product: Core Processor QuickPath Architecture System Address Decoder vendor: Intel Corporation physical id: 102 bus info: pci@0000:ff:00.1 version: 04 width: 32 bits clock: 33MHz *-pci:3 description: Host bridge product: Core Processor QPI Link 0 vendor: Intel Corporation physical id: 103 bus info: pci@0000:ff:02.0 version: 04 width: 32 bits clock: 33MHz *-pci:4 description: Host bridge product: Core Processor QPI Physical 0 vendor: Intel Corporation physical id: 104 bus info: pci@0000:ff:02.1 version: 04 width: 32 bits clock: 33MHz *-pci:5 description: Host bridge product: Core Processor Integrated Memory Controller vendor: Intel Corporation physical id: 105 bus info: pci@0000:ff:03.0 version: 04 width: 32 bits clock: 33MHz *-pci:6 description: Host bridge product: Core Processor Integrated Memory Controller Target Address Decoder vendor: Intel Corporation physical id: 106 bus info: pci@0000:ff:03.1 version: 04 width: 32 bits clock: 33MHz *-pci:7 description: Host bridge product: Core Processor Integrated Memory Controller Test Registers vendor: Intel Corporation physical id: 107 bus info: pci@0000:ff:03.4 version: 04 width: 32 bits clock: 33MHz *-pci:8 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Control Registers vendor: Intel Corporation physical id: 108 bus info: pci@0000:ff:04.0 version: 04 width: 32 bits clock: 33MHz *-pci:9 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Address Registers vendor: Intel Corporation physical id: 109 bus info: pci@0000:ff:04.1 version: 04 width: 32 bits clock: 33MHz *-pci:10 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Rank Registers vendor: Intel Corporation physical id: 10a bus info: pci@0000:ff:04.2 version: 04 width: 32 bits clock: 33MHz *-pci:11 description: Host bridge product: Core Processor Integrated Memory Controller Channel 0 Thermal Control Registers vendor: Intel Corporation physical id: 10b bus info: pci@0000:ff:04.3 version: 04 width: 32 bits clock: 33MHz *-pci:12 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Control Registers vendor: Intel Corporation physical id: 10c bus info: pci@0000:ff:05.0 version: 04 width: 32 bits clock: 33MHz *-pci:13 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Address Registers vendor: Intel Corporation physical id: 10d bus info: pci@0000:ff:05.1 version: 04 width: 32 bits clock: 33MHz *-pci:14 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Rank Registers vendor: Intel Corporation physical id: 10e bus info: pci@0000:ff:05.2 version: 04 width: 32 bits clock: 33MHz *-pci:15 description: Host bridge product: Core Processor Integrated Memory Controller Channel 1 Thermal Control Registers vendor: Intel Corporation physical id: 10f bus info: pci@0000:ff:05.3 version: 04 width: 32 bits clock: 33MHz *-battery description: Lithium Ion Battery product: NK06053 vendor: SMP-ATL24 physical id: 1 slot: Primary capacity: 4800mWh configuration: voltage=11.1V lspci: 02:00.0 USB controller: NEC Corporation uPD720200 USB 3.0 Host Controller (rev 03) (prog-if 30 [XHCI]) Subsystem: Hewlett-Packard Company Device 1522 Flags: bus master, fast devsel, latency 0, IRQ 16 Memory at d4000000 (64-bit, non-prefetchable) [size=8K] Capabilities: [50] Power Management version 3 Capabilities: [70] MSI: Enable- Count=1/8 Maskable- 64bit+ Capabilities: [90] MSI-X: Enable+ Count=8 Masked- Capabilities: [a0] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting Capabilities: [140] Device Serial Number ff-ff-ff-ff-ff-ff-ff-ff Capabilities: [150] Latency Tolerance Reporting Kernel driver in use: xhci_hcd lsusb (with thumb drive plugged into USB3 port): Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub Bus 001 Device 003: ID 5986:01d0 Acer, Inc Bus 001 Device 004: ID 03f0:231d Hewlett-Packard

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• Drivers for NVIDIA 520M not working in Ubuntu 12.04

  - by Don

  I am aware that this is nominally a duplicate question, however I've read the other questions and haven't been able to resolve my problem after many hours and attempts, so please don't delete it. Additionally, it seems like many answers to the other questions are specifically dependent on certain situations. My situation being different from the others I found represented, here's my question. Until last night, I had Ubuntu 12.04 installed with Wubi, and it ran ok, though slowly and with occasional hangs. So I partitioned the drive and installed 12.04 in its own partition. Now when I start it, I am stuck using 2D. I believe this is an NVIDIA bug. My NVIDIA card is a GT 520M and my machine has Optimus. Additional Drivers only displays my wireless driver. Going to System Settings Details Graphics shows Driver:Unknown, Experience:Standard. I downloaded the driver from the NVIDIA website, and ran the installer with no errors, except that the "distribution-provided pre-install script failed". After rebooting, my screen was stuck at 640X480, which was fixed by editing /etc/X11/xorg.conf However, I still was stuck in 2D, and nothing else had changed either. A thread suggested something called Bumblebee. I tried that, and when I ran optirun firefoxI got a frozen blank screen. Following another suggestion, I checked the BIOS to try and disable Optimus. I found and ran myriad other commands to try and fix the problem and nothing changed. Now I have just done a clean re-install of Ubuntu. From there, I: Installed all the updates Downloaded the NVIDIA driver Installed it Got screen stuck at 640X480, fixed in xorg.conf. To recap the problem: I can't get the NVIDIA drivers working I am stuck using 2D I'm an idiot I think if the first one is solved, the solution to the second will naturally follow. If you need me to provide any other information, I'd be happy to. From what I've seen in other threads, I think this information may help: lsmod: dh@donsMachine:~$ lsmod Module Size Used by nvidia 12353161 0 snd_hda_codec_hdmi 32474 1 snd_hda_codec_realtek 223867 1 joydev 17693 0 parport_pc 32866 0 ppdev 17113 0 rfcomm 47604 0 bnep 18281 2 bluetooth 180104 10 rfcomm,bnep snd_hda_intel 33773 3 snd_hda_codec 127706 3 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel snd_hwdep 13668 1 snd_hda_codec snd_pcm 97188 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec uvcvideo 72627 0 videodev 98259 1 uvcvideo v4l2_compat_ioctl32 17128 1 videodev snd_seq_midi 13324 0 snd_rawmidi 30748 1 snd_seq_midi snd_seq_midi_event 14899 1 snd_seq_midi snd_seq 61896 2 snd_seq_midi,snd_seq_midi_event lib80211_crypt_tkip 17390 0 wl 2568210 0 lib80211 14381 2 lib80211_crypt_tkip,wl snd_timer 29990 2 snd_pcm,snd_seq snd_seq_device 14540 3 snd_seq_midi,snd_rawmidi,snd_seq snd 78855 16 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_rawmidi,snd_seq,snd_timer,snd_seq_device psmouse 87692 0 serio_raw 13211 0 i915 468745 2 soundcore 15091 1 snd snd_page_alloc 18529 2 snd_hda_intel,snd_pcm drm_kms_helper 46978 1 i915 drm 242038 3 i915,drm_kms_helper mei 41616 0 i2c_algo_bit 13423 1 i915 mxm_wmi 12979 0 acer_wmi 28418 0 sparse_keymap 13890 1 acer_wmi video 19596 1 i915 wmi 19256 2 mxm_wmi,acer_wmi mac_hid 13253 0 lp 17799 0 parport 46562 3 parport_pc,ppdev,lp tg3 152032 0 sdhci_pci 18826 0 sdhci 33205 1 sdhci_pci lspci -nn | grep VGA dh@donsMachine:~$ lspci -nn | grep VGA 00:02.0 VGA compatible controller [0300]: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0116] (rev 09) 01:00.0 VGA compatible controller [0300]: NVIDIA Corporation Device [10de:0df7] (rev a1) lshw dh@donsMachine:~$ sudo lshw [sudo] password for dh: donsmachine description: Notebook product: EasyNote TS44HR () vendor: Packard Bell version: V1.12 serial: LXBWZ02017134209D71601 width: 64 bits capabilities: smbios-2.7 dmi-2.7 vsyscall32 configuration: boot=normal chassis=notebook uuid=16FE576B-CA15-11E0-B096-B870F4E51243 *-core description: Motherboard product: SJV50_HR vendor: Packard Bell physical id: 0 version: Base Board Version serial: Base Board Serial Number slot: Base Board Chassis Location *-firmware description: BIOS vendor: Packard Bell physical id: 0 version: V1.12 date: 07/11/2011 size: 1MiB capacity: 2496KiB capabilities: pci upgrade shadowing cdboot bootselect edd int13floppynec int13floppytoshiba int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int9keyboard int10video acpi usb biosbootspecification *-memory description: System Memory physical id: 1b slot: System board or motherboard size: 4GiB *-bank:0 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NS-CG vendor: Nanya Technology physical id: 0 serial: 598E126E slot: ChannelA-DIMM0 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:1 description: DIMM [empty] physical id: 1 slot: ChannelA-DIMM1 *-bank:2 description: SODIMM DDR3 Synchronous 1333 MHz (0.8 ns) product: NT2GC64B88B0NS-CG vendor: Nanya Technology physical id: 2 serial: 159E126C slot: ChannelB-DIMM0 size: 2GiB width: 64 bits clock: 1333MHz (0.8ns) *-bank:3 description: DIMM [empty] physical id: 3 slot: ChannelB-DIMM1 *-cpu description: CPU product: Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz vendor: Intel Corp. physical id: 2e bus info: cpu@0 version: Intel(R) Core(TM) i3-2330M CPU @ 2.20GHz slot: CPU1 size: 2GHz capacity: 4GHz width: 64 bits clock: 1333MHz capabilities: x86-64 fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx rdtscp constant_tsc arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic popcnt tsc_deadline_timer xsave avx lahf_lm arat epb xsaveopt pln pts tpr_shadow vnmi flexpriority ept vpid cpufreq configuration: cores=2 enabledcores=2 threads=4 *-cache:0 description: L1 cache physical id: 30 slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through instruction *-cache:1 description: L2 cache physical id: 31 slot: L2 Cache size: 256KiB capacity: 256KiB capabilities: synchronous internal write-through unified *-cache:2 description: L3 cache physical id: 32 slot: L3 Cache size: 3MiB capacity: 3MiB capabilities: synchronous internal write-through unified *-cache description: L1 cache physical id: 2f slot: L1 Cache size: 32KiB capacity: 32KiB capabilities: synchronous internal write-through data *-pci description: Host bridge product: 2nd Generation Core Processor Family DRAM Controller vendor: Intel Corporation physical id: 100 bus info: pci@0000:00:00.0 version: 09 width: 32 bits clock: 33MHz configuration: driver=agpgart-intel resources: irq:0 *-pci:0 description: PCI bridge product: Xeon E3-1200/2nd Generation Core Processor Family PCI Express Root Port vendor: Intel Corporation physical id: 1 bus info: pci@0000:00:01.0 version: 09 width: 32 bits clock: 33MHz capabilities: pci pm msi pciexpress normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:40 ioport:2000(size=4096) memory:d0000000-d10fffff ioport:a0000000(size=301989888) *-display description: VGA compatible controller product: NVIDIA Corporation vendor: NVIDIA Corporation physical id: 0 bus info: pci@0000:01:00.0 version: a1 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress vga_controller bus_master cap_list rom configuration: driver=nvidia latency=0 resources: irq:16 memory:d0000000-d0ffffff memory:a0000000-afffffff memory:b0000000-b1ffffff ioport:2000(size=128) memory:d1000000-d107ffff *-display description: VGA compatible controller product: 2nd Generation Core Processor Family Integrated Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 09 width: 64 bits clock: 33MHz capabilities: msi pm vga_controller bus_master cap_list rom configuration: driver=i915 latency=0 resources: irq:43 memory:d1400000-d17fffff memory:c0000000-cfffffff ioport:3000(size=64) *-communication description: Communication controller product: 6 Series/C200 Series Chipset Family MEI Controller #1 vendor: Intel Corporation physical id: 16 bus info: pci@0000:00:16.0 version: 04 width: 64 bits clock: 33MHz capabilities: pm msi bus_master cap_list configuration: driver=mei latency=0 resources: irq:42 memory:d1a04000-d1a0400f *-usb:0 description: USB controller product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #2 vendor: Intel Corporation physical id: 1a bus info: pci@0000:00:1a.0 version: 04 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:16 memory:d1a0a000-d1a0a3ff *-multimedia description: Audio device product: 6 Series/C200 Series Chipset Family High Definition Audio Controller vendor: Intel Corporation physical id: 1b bus info: pci@0000:00:1b.0 version: 04 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=snd_hda_intel latency=0 resources: irq:44 memory:d1a00000-d1a03fff *-pci:1 description: PCI bridge product: 6 Series/C200 Series Chipset Family PCI Express Root Port 1 vendor: Intel Corporation physical id: 1c bus info: pci@0000:00:1c.0 version: b4 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:17 memory:9fb00000-9fbfffff ioport:d1800000(size=1048576) *-network description: Ethernet interface product: NetLink BCM57785 Gigabit Ethernet PCIe vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:02:00.0 logical name: eth0 version: 10 serial: b8:70:f4:e5:12:43 capacity: 1Gbit/s width: 64 bits clock: 33MHz capabilities: pm msi msix pciexpress bus_master cap_list rom ethernet physical tp 10bt 10bt-fd 100bt 100bt-fd 1000bt 1000bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=tg3 driverversion=3.121 firmware=sb latency=0 link=no multicast=yes port=twisted pair resources: irq:16 memory:d1830000-d183ffff memory:d1840000-d184ffff memory:d1850000-d18507ff *-generic:0 description: SD Host controller product: NetXtreme BCM57765 Memory Card Reader vendor: Broadcom Corporation physical id: 0.1 bus info: pci@0000:02:00.1 version: 10 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: driver=sdhci-pci latency=0 resources: irq:17 memory:d1800000-d180ffff *-generic:1 UNCLAIMED description: System peripheral product: Broadcom Corporation vendor: Broadcom Corporation physical id: 0.2 bus info: pci@0000:02:00.2 version: 10 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:d1810000-d181ffff *-generic:2 UNCLAIMED description: System peripheral product: Broadcom Corporation vendor: Broadcom Corporation physical id: 0.3 bus info: pci@0000:02:00.3 version: 10 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list configuration: latency=0 resources: memory:d1820000-d182ffff *-pci:2 description: PCI bridge product: 6 Series/C200 Series Chipset Family PCI Express Root Port 2 vendor: Intel Corporation physical id: 1c.1 bus info: pci@0000:00:1c.1 version: b4 width: 32 bits clock: 33MHz capabilities: pci pciexpress msi pm normal_decode bus_master cap_list configuration: driver=pcieport resources: irq:16 memory:d1900000-d19fffff *-network description: Wireless interface product: BCM43225 802.11b/g/n vendor: Broadcom Corporation physical id: 0 bus info: pci@0000:03:00.0 logical name: eth1 version: 01 serial: 68:a3:c4:44:81:96 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=wl0 driverversion=5.100.82.38 ip=192.168.0.12 latency=0 multicast=yes wireless=IEEE 802.11bgn resources: irq:17 memory:d1900000-d1903fff *-usb:1 description: USB controller product: 6 Series/C200 Series Chipset Family USB Enhanced Host Controller #1 vendor: Intel Corporation physical id: 1d bus info: pci@0000:00:1d.0 version: 04 width: 32 bits clock: 33MHz capabilities: pm debug ehci bus_master cap_list configuration: driver=ehci_hcd latency=0 resources: irq:23 memory:d1a09000-d1a093ff *-isa description: ISA bridge product: HM65 Express Chipset Family LPC Controller vendor: Intel Corporation physical id: 1f bus info: pci@0000:00:1f.0 version: 04 width: 32 bits clock: 33MHz capabilities: isa bus_master cap_list configuration: latency=0 *-storage description: SATA controller product: 6 Series/C200 Series Chipset Family 6 port SATA AHCI Controller vendor: Intel Corporation physical id: 1f.2 bus info: pci@0000:00:1f.2 logical name: scsi0 logical name: scsi1 version: 04 width: 32 bits clock: 66MHz capabilities: storage msi pm ahci_1.0 bus_master cap_list emulated configuration: driver=ahci latency=0 resources: irq:41 ioport:3098(size=8) ioport:30bc(size=4) ioport:3090(size=8) ioport:30b8(size=4) ioport:3060(size=32) memory:d1a08000-d1a087ff *-disk description: ATA Disk product: ST9500325AS vendor: Seagate physical id: 0 bus info: scsi@0:0.0.0 logical name: /dev/sda version: 0001 serial: S2W1AMSX size: 465GiB (500GB) capabilities: partitioned partitioned:dos configuration: ansiversion=5 signature=a45f21e9 *-volume:0 description: Windows NTFS volume physical id: 1 bus info: scsi@0:0.0.0,1 logical name: /dev/sda1 version: 3.1 serial: 46aa-2a25 size: 19GiB capacity: 20GiB capabilities: primary ntfs initialized configuration: clustersize=4096 created=2011-08-25 21:32:00 filesystem=ntfs label=PQSERVICE state=clean *-volume:1 description: Windows NTFS volume physical id: 2 bus info: scsi@0:0.0.0,2 logical name: /dev/sda2 version: 3.1 serial: 10aa-ad1a size: 98MiB capacity: 100MiB capabilities: primary bootable ntfs initialized configuration: clustersize=4096 created=2011-08-25 21:32:03 filesystem=ntfs label=SYSTEM RESERVED state=clean *-volume:2 description: Windows NTFS volume physical id: 3 bus info: scsi@0:0.0.0,3 logical name: /dev/sda3 version: 3.1 serial: 668c5afc-182e-ff4b-b084-3cc09f54972d size: 395GiB capacity: 395GiB capabilities: primary ntfs initialized configuration: clustersize=4096 created=2011-08-25 21:32:03 filesystem=ntfs label=Don's Machine state=clean *-volume:3 description: Extended partition physical id: 4 bus info: scsi@0:0.0.0,4 logical name: /dev/sda4 size: 49GiB capacity: 49GiB capabilities: primary extended partitioned partitioned:extended *-logicalvolume:0 description: Linux swap / Solaris partition physical id: 5 logical name: /dev/sda5 capacity: 3945MiB capabilities: nofs *-logicalvolume:1 description: Linux filesystem partition physical id: 6 logical name: /dev/sda6 logical name: / capacity: 46GiB configuration: mount.fstype=ext4 mount.options=rw,relatime,errors=remount-ro,user_xattr,barrier=1,data=ordered state=mounted *-cdrom description: DVD-RAM writer product: DVD-RW DVRTD11RS vendor: PIONEER physical id: 1 bus info: scsi@1:0.0.0 logical name: /dev/cdrom logical name: /dev/cdrw logical name: /dev/dvd logical name: /dev/dvdrw logical name: /dev/sr0 version: 1.01 capabilities: removable audio cd-r cd-rw dvd dvd-r dvd-ram configuration: ansiversion=5 status=nodisc *-serial UNCLAIMED description: SMBus product: 6 Series/C200 Series Chipset Family SMBus Controller vendor: Intel Corporation physical id: 1f.3 bus info: pci@0000:00:1f.3 version: 04 width: 64 bits clock: 33MHz configuration: latency=0 resources: memory:d1a06000-d1a060ff ioport:3040(size=32) *-power UNCLAIMED description: OEM_Define1 product: OEM_Define5 vendor: OEM_Define2 physical id: 1 version: OEM_Define6 serial: OEM_Define3 capacity: 75mWh *-battery description: Lithium Ion Battery product: CRB Battery 0 vendor: -Virtual Battery 0- physical id: 2 version: 10/12/2007 serial: Battery 0 slot: Fake

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• A tale from a Stalker

  - by Peter Larsson

  Today I thought I should write something about a stalker I've got. Don't get me wrong, I have way more fans than stalkers, but this stalker is particular persistent towards me. It all started when I wrote about Relational Division with Sets late last year(http://weblogs.sqlteam.com/peterl/archive/2010/07/02/Proper-Relational-Division-With-Sets.aspx) and no matter what he tried, he didn't get a better performing query than me. But this I didn't click until later into this conversation. He must have saved himself for 9 months before posting to me again. Well... Some days ago I get an email from someone I thought i didn't know. Here is his first email Hi, I want a proper solution for achievement the result. The solution must be standard query, means no using as any native code like TOP clause, also the query should run in SQL Server 2000 (no CTE use). We have a table with consecutive keys (nbr) that is not exact sequence. We need bringing all values related with nearest key in the current key row. See the DDL: CREATE TABLE Nums(nbr INTEGER NOT NULL PRIMARY KEY, val INTEGER NOT NULL); INSERT INTO Nums(nbr, val) VALUES (1, 0),(5, 7),(9, 4); See the Result: pre_nbr     pre_val     nbr         val         nxt_nbr     nxt_val ----------- ----------- ----------- ----------- ----------- ----------- NULL        NULL        1           0           5           7 1           0           5           7           9           4 5           7           9           4           NULL        NULL The goal is suggesting most elegant solution. I would like see your best solution first, after that I will send my best (if not same with yours)   Notice there is no name, no please or nothing polite asking for my help. So, on the top of my head I sent him two solutions, following the rule "Work on SQL Server 2000 and only standard non-native code".     -- Peso 1 SELECT               pre_nbr,                              (                                                           SELECT               x.val                                                           FROM                dbo.Nums AS x                                                           WHERE              x.nbr = d.pre_nbr                              ) AS pre_val,                              d.nbr,                              d.val,                              d.nxt_nbr,                              (                                                           SELECT               x.val                                                           FROM                dbo.Nums AS x                                                           WHERE              x.nbr = d.nxt_nbr                              ) AS nxt_val FROM                (                                                           SELECT               (                                                                                                                     SELECT               MAX(x.nbr) AS nbr                                                                                                                     FROM                dbo.Nums AS x                                                                                                                     WHERE              x.nbr < n.nbr                                                                                        ) AS pre_nbr,                                                                                        n.nbr,                                                                                        n.val,                                                                                        (                                                                                                                     SELECT               MIN(x.nbr) AS nbr                                                                                                                     FROM                dbo.Nums AS x                                                                                                                     WHERE              x.nbr > n.nbr                                                                                        ) AS nxt_nbr                                                           FROM                dbo.Nums AS n                              ) AS d -- Peso 2 CREATE TABLE #Temp                                                         (                                                                                        ID INT IDENTITY(1, 1) PRIMARY KEY,                                                                                        nbr INT,                                                                                        val INT                                                           )   INSERT                                            #Temp                                                           (                                                                                        nbr,                                                                                        val                                                           ) SELECT                                            nbr,                                                           val FROM                                             dbo.Nums ORDER BY         nbr   SELECT                                            pre.nbr AS pre_nbr,                                                           pre.val AS pre_val,                                                           t.nbr,                                                           t.val,                                                           nxt.nbr AS nxt_nbr,                                                           nxt.val AS nxt_val FROM                                             #Temp AS pre RIGHT JOIN      #Temp AS t ON t.ID = pre.ID + 1 LEFT JOIN         #Temp AS nxt ON nxt.ID = t.ID + 1   DROP TABLE    #Temp Notice there are no indexes on #Temp table yet. And here is where the conversation derailed. First I got this response back Now my solutions: --My 1st Slt SELECT T2.*, T1.*, T3.*   FROM Nums AS T1        LEFT JOIN Nums AS T2          ON T2.nbr = (SELECT MAX(nbr)                         FROM Nums                        WHERE nbr < T1.nbr)        LEFT JOIN Nums AS T3          ON T3.nbr = (SELECT MIN(nbr)                         FROM Nums                        WHERE nbr > T1.nbr); --My 2nd Slt SELECT MAX(CASE WHEN N1.nbr > N2.nbr THEN N2.nbr ELSE NULL END) AS pre_nbr,        (SELECT val FROM Nums WHERE nbr = MAX(CASE WHEN N1.nbr > N2.nbr THEN N2.nbr ELSE NULL END)) AS pre_val,        N1.nbr AS cur_nbr, N1.val AS cur_val,        MIN(CASE WHEN N1.nbr < N2.nbr THEN N2.nbr ELSE NULL END) AS nxt_nbr,        (SELECT val FROM Nums WHERE nbr = MIN(CASE WHEN N1.nbr < N2.nbr THEN N2.nbr ELSE NULL END)) AS nxt_val   FROM Nums AS N1,        Nums AS N2  GROUP BY N1.nbr, N1.val;   /* My 1st Slt Table 'Nums'. Scan count 7, logical reads 14 My 2nd Slt Table 'Nums'. Scan count 4, logical reads 23 Peso 1 Table 'Nums'. Scan count 9, logical reads 28 Peso 2 Table '#Temp'. Scan count 0, logical reads 7 Table 'Nums'. Scan count 1, logical reads 2 Table '#Temp'. Scan count 3, logical reads 16 */  To this, I emailed him back asking for a scalability test What if you try with a Nums table with 100,000 rows? His response to that started to get nasty.  I have to say Peso 2 is not acceptable. As I said before the solution must be standard, ORDER BY is not part of standard SELECT. Try this without ORDER BY:  Truncate Table Nums INSERT INTO Nums (nbr, val) VALUES (1, 0),(9,4), (5, 7)  So now we have new rules. No ORDER BY because it's not standard SQL! Of course I asked him  Why do you have that idea? ORDER BY is not standard? To this, his replies went stranger and stranger Standard Select = Set-based (no any cursor) It’s free to know, just refer to Advanced SQL Programming by Celko or mail to him if you accept comments from him. What the stalker probably doesn't know, is that I and Mr Celko occasionally are involved in some conversation and thus we exchange emails. I don't know if this reference to Mr Celko was made to intimidate me either. So I answered him, still polite, this What do you mean? The SELECT itself has a ”cursor under the hood”. Now the stalker gets rude  But however I mean the solution must no containing any order by, top... No problem, I do not like Peso 2, it’s very non-intelligent and elementary. Yes, Peso 2 is elementary but most performing queries are... And now is the time where I started to feel the stalker really wanted to achieve something else, so I wrote to him So what is your goal? Have a query that performs well, or a query that is super-portable? My Peso 2 outperforms any of your code with a factor of 100 when using more than 100,000 rows. While I awaited his answer, I posted him this query Ok, here is another one -- Peso 3 SELECT             MAX(CASE WHEN d = 1 THEN nbr ELSE NULL END) AS pre_nbr,                    MAX(CASE WHEN d = 1 THEN val ELSE NULL END) AS pre_val,                    MAX(CASE WHEN d = 0 THEN nbr ELSE NULL END) AS nbr,                    MAX(CASE WHEN d = 0 THEN val ELSE NULL END) AS val,                    MAX(CASE WHEN d = -1 THEN nbr ELSE NULL END) AS nxt_nbr,                    MAX(CASE WHEN d = -1 THEN val ELSE NULL END) AS nxt_val FROM               (                              SELECT    nbr,                                        val,                                        ROW_NUMBER() OVER (ORDER BY nbr) AS SeqID                              FROM      dbo.Nums                    ) AS s CROSS JOIN         (                              VALUES    (-1),                                        (0),                                        (1)                    ) AS x(d) GROUP BY           SeqID + x.d HAVING             COUNT(*) > 1 And here is the stats Table 'Nums'. Scan count 1, logical reads 2, physical reads 0, read-ahead reads 0, lob logical reads 0, lob physical reads 0, lob read-ahead reads 0. It beats the hell out of your queries…. Now I finally got a response from my stalker and now I also clicked who he was. This is his reponse Why you post my original method with a bit change under you name? I do not like it. See: http://www.sqlservercentral.com/Forums/Topic468501-362-14.aspx ;WITH C AS ( SELECT seq_nbr, k,        DENSE_RANK() OVER(ORDER BY seq_nbr ASC) + k AS grp_fct   FROM [Sample]         CROSS JOIN         (VALUES (-1), (0), (1)         ) AS D(k) ) SELECT MIN(seq_nbr) AS pre_value,        MAX(CASE WHEN k = 0 THEN seq_nbr END) AS current_value,        MAX(seq_nbr) AS next_value   FROM C GROUP BY grp_fct HAVING min(seq_nbr) < max(seq_nbr); These posts: Posted Tuesday, April 12, 2011 10:04 AM Posted Tuesday, April 12, 2011 1:22 PM Why post a solution where will not work in SQL Server 2000? Wait a minute! His own solution is using both a CTE and a ranking function so his query will not work on SQL Server 2000! Bummer... The reference to "Me not like" are my exact words in a previous topic on SQLTeam.com and when I remembered the phrasing, I also knew who he was. See this topic http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=159262 where he writes a query and posts it under my name, as if I wrote it. So I answered him this (less polite). Like I keep track of all topics in the whole world… J So you think you are the only one coming up with this idea? Besides, “M S solution” doesn’t work.   This is the result I get pre_value        current_value                             next_value 1                           1                           5 1                           5                           9 5                           9                           9   And I did nothing like you did here, where you posted a solution which you “thought” I should write http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=159262 So why are you yourself using ranking function when this was not allowed per your original email, and no cte? You use CTE in your link above, which do not work in SQL Server 2000. All this makes no sense to me, other than you are trying your best to once in a lifetime create a better performing query than me? After a few hours I get this email back. I don't fully understand it, but it's probably a language barrier. >>Like I keep track of all topics in the whole world… J So you think you are the only one coming up with this idea?<< You right, but do not think you are the first creator of this.   >>Besides, “M S Solution” doesn’t work. This is the result I get <<   Why you get so unimportant mistake? See this post to correct it: Posted 4/12/2011 8:22:23 PM >> So why are you yourself using ranking function when this was not allowed per your original email, and no cte? You use CTE in your link above, which do not work in SQL Server 2000. <<  Again, why you get some unimportant incompatibility? You offer that solution for current goals not me  >> All this makes no sense to me, other than you are trying your best to once in a lifetime create a better performing query than me? <<  No, I only wanted to know who you will solve it. Now I know you do not have a special solution. No problem. No problem for me either. So I just answered him I am not the first, and you are not the first to come up with this idea. So what is your problem? I am pretty sure other people have come up with the same idea before us. I used this technique all the way back to 2007, see http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=93911 Let's see if he returns...  He did! >> So what is your problem? << Nothing Thanks for all replies; maybe we have some competitions in future, maybe. Also I like you but you do not attend it. Your behavior with me is not friendly. Not any meeting… Regards //Peso

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• How can I handle parameterized queries in Drupal?

  - by Anthony Gatlin

  We have a client who is currently using Lotus Notes/Domino as their content management system and web server. For many reasons, we are recommending they sunset their Notes/Domino implementation and transition onto a more modern platform--such as Drupal. The client has several web applications which would be a natural fit for Drupal. However, I am unsure of the best way to implement one of the web applications in Drupal. I am running into a knowledge barrier and wondered if any of you could fill in the gaps. Situation The client has a Lotus Domino application which serves as a front-end for querying a large DB2 data store and returning a result set (generally in table form) to a user via the web. The web application provides access to approximately 100 pre-defined queries--50 of which are public and 50 of which are secured. Most of the queries accept some set of user selected parameters as input. The output of the queries is typically returned to users in a list (table) format. A limited number of result sets allow drill-down through the HTML table into detail records. The query parameters often involve database queries themselves. For example, a single query may pull a list of company divisions into a drop-down. Once a division is selected, second drop-down with the departments from that division is populated--but perhaps only departments which meet some special criteria--such as those having taken a loss within a specific time frame. Most queries have 2-4 parameters with the average probably being 3. The application involves no data entry. None of the back-end data is ever modified by the web application. All access is purely based around querying data and viewing results. The queries change relatively infrequently, and the current system has been in place for approximately 10 years. There may be 10-20 query additions, modifications, or other changes in a given year. The client simply desires to change the presentation platform but absolutely does not want to re-do the 100 database queries. Once the project is implemented, the client wants their staff to take over and manage future changes. The client's staff have no background in Drupal or PHP but are somewhat willing to learn as necessary. How would you transition this into Drupal? My major knowledge void relates to how we would manage the query parameters and access the queries themselves. Here are a few specific questions but feel free to chime in on any issue related to this implementation. Would we have to build 100 forms by hand--with each form containing the parameters for a given query? If so, how would we do this? Approximately how long would it take to build/configure each of these forms? Is there a better way than manually building 100 forms? (I understand using CCK to enter data into custom content types but since we aren't adding any nodes, I am a little stuck as to how this might work.) Would it be possible for the internal staff to learn to create these query parameter forms--even if they are unfamiliar with Drupal today? Would they be required to do any PHP programming? How would we take the query parameters from a form and execute a query against DB2? Would this require a custom module? If so, would it require one module total or one module per query? (Note: There is apparently a DB2 driver available for Drupal. See http://groups.drupal.org/node/5511.) Note: I am not looking for CMS recommendations other than Drupal as Drupal nicely fits all of the client's other requirements, and I hope to help them standardize on a single platform. Any assistance you can provide would be helpful. Thank you in advance for your help!

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• Cross Browser Issue

  - by dazedandconfused

  My background is in WinForms programming and I'm trying to branch out a bit. I'm finding cross-browser issues a frustrating barrier in general, but have a specific one that I just can't seem to work through. I want to display an image and place a semi-transparent bar across the top and bottom. This isn't my ultimate goal, of course, but it demonstrates the problem I'm having ina a relatively short code fragment so let's go with it. The sample code below displays as intended in Chrome, Safari, and Firefox. In IE8, the bar at the bottom doesn't appear at all. I've researched it for hours but just can't seem to come up with the solution. I'm sure this is some dumb rookie mistake, but gotta start somewhere. Code snippet... <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title></title> <script type="text/javascript" language="javascript"> </script> <style type="text/css"> .workarea { position: relative; border: 1px solid black; background-color: #ccc; overflow: hidden; cursor: move; -moz-user-focus: normal; -moz-user-select: none; unselectable: on; } .semitransparent { filter: alpha(opacity=70); -moz-opacity: 0.7; -khtml-opacity: 0.7; opacity: 0.7; background-color: Gray; } </style> </head> <body style="width: 800px; height: 600px;"> <div id="workArea" class="workarea" style="width: 800px; height: 350px; left: 100px; top: 50px; background-color: White; border: 1px solid black;"> <img alt="" src="images/TestImage.jpg" style="left: 0px; top: 0px; border: none; z-index: 1;" /> <div id="topBar" class="semitransparent" style="position: absolute;width: 800px; height: 75px; left: 0px; top: 0px; min-height: 75px; border: none; z-index: 2;" /> <div id="bottomBar" class="semitransparent" style="position: absolute; width: 800px; height: 75px; left: 0px; top: 275px; min-height: 75px; border: none; z-index: 2;" /> </div> </body> </html>

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• Sharing a UIView between UIViewControllers in a UITabBarController

  - by Wireless Designs

  Hi all - I have a UIScrollView that houses a gallery of images the user can scroll through. This view needs to be visible on each of three separate UIViewControllers that are housed within a UITabBarController. Right now, I have three separate UIScrollView instances in the UITabBarController subclass, and the controller manages keeping the three synchronized (when a user scrolls the one they can see, programmatically scrolling the other two to match, etc.), which is not ideal. I would like to know if there is a way to work with only ONE instance of the UIScrollView, but have it show up only in the UIViewController that the user is currently interacting with. This would completely eliminate all the synchronization code. Here is basically what I have now in the UITabBarController (which is where all this is currently managed): @interface ScrollerTabBarController : UITabBarController { FirstViewController *firstView; SecondViewController *secondView; ThirdViewController *thirdView; UIScrollView *scrollerOne; UIScrollView *scrollerTwo; UIScrollView *scrollerThree; } @property (nonatomic,retain) IBOutlet FirstViewController *firstView; @property (nonatomic,retain) IBOutlet SecondViewController *secondView; @property (nonatomic,retain) IBOutlet ThirdViewController *thirdView; @property (nonatomic,retain) IBOutlet UIScrollView *scrollerOne; @property (nonatomic,retain) IBOutlet UIScrollView *scrollerTwo; @property (nonatomic,retain) IBOutlet UIScrollView *scrollerThree; @end @implementation ScrollerTabBarController - (void)layoutScroller:(UIScrollView *)scroller {} - (void)scrollToMatch:(UIScrollView *)scroller {} - (void)viewDidLoad { [self layoutScroller:scrollerOne]; [self layoutScroller:scrollerTwo]; [self layoutScroller:scrollerThree]; [scrollerOne setDelegate:self]; [scrollerTwo setDelegate:self]; [scrollerThree setDelegate:self]; [firstView setGallery:scrollerOne]; [secondView setGallery:scrollerTwo]; [thirdView setGallery:scrollerThree]; } - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView { [self scrollToMatch:scrollView]; } @end The UITabBarController gets notified (as the scroll view's delegate) when the user scrolls one of the instances, and then calls methods like scrollToMatch: to sync up the other two with the user's choice. Is there something that can be done, using a many-to-one relationship on IBOutlet or something like that, to narrow this down to one instance so I'm not having to manage three scroll views? I tried keeping a single instance and moving the pointer from one view to the next using the UITabBarControllerDelegate methods (calling setGallery:nil on the current and setGallery:scrollerOne on the next each time it changed), but the scroller never moved to the other tabs. Thanks in advance!

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• Asynchronous readback from opengl front buffer using multiple PBO's

  - by KillianDS

  I am developing an application that needs to read back the whole frame from the front buffer of an openGL application. I can hijack the application's opengl library and insert my code on swapbuffers. At the moment I am successfully using a simple but excruciating slow glReadPixels command without PBO's. Now I read about using multiple PBO's to speed things up. While I think I've found enough resources to actually program that (isn't that hard), I have some operational questions left. I would do something like this: create a series (e.g. 3) of PBO's use glReadPixels in my swapBuffers override to read data from front buffer to a PBO (should be fast and non-blocking, right?) Create a seperate thread to call glMapBufferARB, once per PBO after a glReadPixels, because this will block until the pixels are in client memory. Process the data from step 3. Now my main concern is of course in steps 2 and 3. I read about glReadPixels used on PBO's being non-blocking, will this be an issue if I issue new opengl commands after that very fast? Will those opengl commands block? Or will they continue (my guess), and if so, I guess only swapbuffers can be a problem, will this one stall or will glReadPixels from front buffer be many times faster than swapping (about each 15-30ms) or, worst case scenario, will swapbuffers be executed while glReadPixels is still reading data to the PBO? My current guess is this logic will do something like this: copy FRONT_BUFFER - generic place in VRAM, copy VRAM-RAM. But I have no idea which of those 2 is the real bottleneck and more, what the influence on the normal opengl command stream is. Then in step 3. Is it wise to do this asynchronously in a thread separated from normal opengl logic? At the moment I think not, It seems you have to restore buffer operations to normal after doing this and I can't install synchronization objects in the original code to temporarily block those. So I think my best option is to define a certain swapbuffer delay before reading them out, so e.g. calling glReadPixels on PBO i%3 and glMapBufferARB on PBO (i+2)%3 in the same thread, resulting in a delay of 2 frames. Also, when I call glMapBufferARB to use data in client memory, will this be the bottleneck or will glReadPixels (asynchronously) be the bottleneck? And finally, if you have some better ideas to speed up frame readback from GPU in opengl, please tell me, because this is a painful bottleneck in my current system. I hope my question is clear enough, I know the answer will probably also be somewhere on the internet but I mostly came up with results that used PBO's to keep buffers in video memory and do processing there. I really need to read back the front buffer to RAM and I do not find any clear explanations about performance in that case (which I need, I cannot rely on "it's faster", I need to explain why it's faster). Thank you

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• Make Bluetooth on Android 2.1 discoverable indefinitely

  - by kanov-baekonfat

  Hello all. I'm working on a research project which involves Bluetooth and the Android OS. I need to make Bluetooth discoverable indefinitely in order for the project to continue. The Problem: Android limits discoverability to 300 seconds. I cannot ask the user every 300 seconds to turn discoverability back on as my application is designed to run in the background without disturbing the user. As far as I am aware, there is no way to increase the time though Android's GUI. Some sources have called this a safety feature, others have called this a bug. There may be a bit of truth in both... What I'm Trying / Have Tried: I'm trying to edit a stable release of cyanogenmod to turn the discoverability timer off (it's possible; there's a configuration file that needs to have a single number changed). This isn't working because I'm having verification problems with the resulting package. During the past week, I downloaded the cyanogenmod source code, changed a relevant class in the hope that it would make Bluetooth discoverable indefinitely, and tried to recompile. This did not work because (a) the repo is frequently changed, leading to an unstable code base which fails to compile (OR, it could be that I'm using it incorrectly; just because it looked like it was the code's fault in many instances doesn't mean I should blame it for all the problems I encountered!) and (b) the repo decides to periodically "ignore" me (but not always, as I have gotten the code base before!), replying to my synchronization/connection attempts with: fatal: The remote end hung up unexpectedly As you might imagine, the above two issues are problematic and very frustrating to deal with. More Info: I'm running Android 2.1 via cyanogenmod (v5 I believe). This means the phone is also rooted. I have a developer phone, which means that the bootloader is unlocked. My phone is an HTC Magic (32B). The Big Question: How can I make Bluetooth indefinitely discoverable on Android? Thanks for your time and input. I feel like I'm spinning my tires on this issue and I'd like to move past it.

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• Windows forms application blocks after station lock

  - by Silviu

  We're having a serious issue at work. We've discovered that after the station where the client was running is locked/unlocked the client is blocked. No repaint. So the UI thread is blocked with something. Looking at the callstack of the UI thread (thread 0) using windbg we see that a UserPreferenceChanged event gets raised. It is marshalled through a WindowsFormsSynchronizationContext using it's controlToSend field to the UI. It gets blocked by a call to the marshalling control. The method called is MarshaledInvoke it builds a ThreadMethodEntry entry = new ThreadMethodEntry(caller, method, args, synchronous, executionContext); This entry is supposed to do the magic. The call is a synchronous call and because of that (still in the MarshaledInvoke of the Control class) the wait call is reached: if (!entry.IsCompleted) { this.WaitForWaitHandle(entry.AsyncWaitHandle); } The last thing that i can see on the stack is the WaitOne called on the previously mentioned AsyncWaitHandle. This is very annoying because having just the callstack of the runtime and not one of our methods being invoked we cannot really point to a bug in our code. I might be wrong, but I'm guessing that the marshaling control is not "marshaling" to the ui thread. But another one...i don't really know which one because the other threads are being used by us and are blocked...maybe this is the issue. But none of the other threads are running a message loop. This is very annoying. We had some issues in the past with marshaling controls to the right ui thread. That is because the first form that is constructed is a splash form. Which is not the main form. We used to use the main form to marshal call to the ui thread. But from time to time some calls would go to a non ui thread and some grids would broke with a big red X on them. I fixed this by creating a specific class: public class WindowsFormsSynchronizer { private static readonly WindowsFormsSynchronizationContext = new WindowsFormsSynchronizationContext(); //Methods are following that would build the same interface of the synchronization context. } This class gets build as one of the first objects in the first form being constructed. We've noticed some other strange thing. Looking at the heap there are 7 WindowsFormsSynchronizationContext objects. 6 of these have the same instance of controlToSend, and the other one has some different instance of controlToSend. This last one is the one that should marshal the calls to the UI. I don't have any other idea...maybe some of you guys had this same issue?

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