Search Results

Search found 1544 results on 62 pages for 'heap corruption'.

Page 57/62 | < Previous Page | 53 54 55 56 57 58 59 60 61 62  | Next Page >

• Cannot SSH to ubuntu server - openssh server owner changed

  - by Kshitiz Shankar

  I am using suPHP with Apache for virtual hosting but somewhere down the line my root ssh access is getting screwed up. I haven't been able to figure out why it is happening but eventually, my root user is not able to ssh to the server. I get this error: *** invalid open call: O_CREAT without mode ***: sshd: root@pts/3 terminated ======= Backtrace: ========= /lib/x86_64-linux-gnu/libc.so.6(__fortify_fail+0x37)[0x7f12fe871817] /lib/x86_64-linux-gnu/libc.so.6(+0xeb7e1)[0x7f12fe8527e1] sshd: root@pts/3[0x41a542] sshd: root@pts/3[0x41a9eb] sshd: root@pts/3[0x41aeb8] sshd: root@pts/3[0x409630] sshd: root@pts/3[0x40f9ed] sshd: root@pts/3[0x410dd6] sshd: root@pts/3[0x411994] sshd: root@pts/3[0x411f16] sshd: root@pts/3[0x40b253] sshd: root@pts/3[0x42be24] sshd: root@pts/3[0x40c9cb] sshd: root@pts/3[0x412199] sshd: root@pts/3[0x4061a2] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7f12fe78876d] sshd: root@pts/3[0x407635] ======= Memory map: ======== 00400000-00448000 r-xp 00000000 ca:02 4554758 /usr/sbin/sshd 00647000-00648000 r--p 00047000 ca:02 4554758 /usr/sbin/sshd 00648000-00649000 rw-p 00048000 ca:02 4554758 /usr/sbin/sshd 00649000-00750000 rw-p 00000000 00:00 0 01794000-017b5000 rw-p 00000000 00:00 0 [heap] 7f12fd5ad000-7f12fd5c2000 r-xp 00000000 ca:02 3489844 /lib/x86_64-linux-gnu/libgcc_s.so.1 7f12fd5c2000-7f12fd7c1000 ---p 00015000 ca:02 3489844 /lib/x86_64-linux-gnu/libgcc_s.so.1 7f12fd7c1000-7f12fd7c2000 r--p 00014000 ca:02 3489844 /lib/x86_64-linux-gnu/libgcc_s.so.1 7f12fd7c2000-7f12fd7c3000 rw-p 00015000 ca:02 3489844 /lib/x86_64-linux-gnu/libgcc_s.so.1 7f12fd7c3000-7f12fd7db000 r-xp 00000000 ca:02 3489977 /lib/x86_64-linux-gnu/libresolv-2.15.so 7f12fd7db000-7f12fd9db000 ---p 00018000 ca:02 3489977 /lib/x86_64-linux-gnu/libresolv-2.15.so 7f12fd9db000-7f12fd9dc000 r--p 00018000 ca:02 3489977 /lib/x86_64-linux-gnu/libresolv-2.15.so 7f12fd9dc000-7f12fd9dd000 rw-p 00019000 ca:02 3489977 /lib/x86_64-linux-gnu/libresolv-2.15.so 7f12fd9dd000-7f12fd9df000 rw-p 00000000 00:00 0 7f12fd9df000-7f12fd9e6000 r-xp 00000000 ca:02 3489994 /lib/x86_64-linux-gnu/libnss_dns-2.15.so 7f12fd9e6000-7f12fdbe5000 ---p 00007000 ca:02 3489994 /lib/x86_64-linux-gnu/libnss_dns-2.15.so 7f12fdbe5000-7f12fdbe6000 r--p 00006000 ca:02 3489994 /lib/x86_64-linux-gnu/libnss_dns-2.15.so 7f12fdbe6000-7f12fdbe7000 rw-p 00007000 ca:02 3489994 /lib/x86_64-linux-gnu/libnss_dns-2.15.so 7f12fdbe7000-7f12fdd27000 rw-s 00000000 00:04 6167294 /dev/zero (deleted) 7f12fdd27000-7f12fdd33000 r-xp 00000000 ca:02 3489984 /lib/x86_64-linux-gnu/libnss_files-2.15.so 7f12fdd33000-7f12fdf32000 ---p 0000c000 ca:02 3489984 /lib/x86_64-linux-gnu/libnss_files-2.15.so 7f12fdf32000-7f12fdf33000 r--p 0000b000 ca:02 3489984 /lib/x86_64-linux-gnu/libnss_files-2.15.so 7f12fdf33000-7f12fdf34000 rw-p 0000c000 ca:02 3489984 /lib/x86_64-linux-gnu/libnss_files-2.15.so 7f12fdf34000-7f12fdf3e000 r-xp 00000000 ca:02 3489979 /lib/x86_64-linux-gnu/libnss_nis-2.15.so 7f12fdf3e000-7f12fe13e000 ---p 0000a000 ca:02 3489979 /lib/x86_64-linux-gnu/libnss_nis-2.15.so 7f12fe13e000-7f12fe13f000 r--p 0000a000 ca:02 3489979 /lib/x86_64-linux-gnu/libnss_nis-2.15.so 7f12fe13f000-7f12fe140000 rw-p 0000b000 ca:02 3489979 /lib/x86_64-linux-gnu/libnss_nis-2.15.so 7f12fe140000-7f12fe157000 r-xp 00000000 ca:02 3489996 /lib/x86_64-linux-gnu/libnsl-2.15.so 7f12fe157000-7f12fe356000 ---p 00017000 ca:02 3489996 /lib/x86_64-linux-gnu/libnsl-2.15.so 7f12fe356000-7f12fe357000 r--p 00016000 ca:02 3489996 /lib/x86_64-linux-gnu/libnsl-2.15.so 7f12fe357000-7f12fe358000 rw-p 00017000 ca:02 3489996 /lib/x86_64-linux-gnu/libnsl-2.15.so 7f12fe358000-7f12fe35a000 rw-p 00000000 00:00 0 7f12fe35a000-7f12fe362000 r-xp 00000000 ca:02 3489985 /lib/x86_64-linux-gnu/libnss_compat-2.15.so 7f12fe362000-7f12fe561000 ---p 00008000 ca:02 3489985 /lib/x86_64-linux-gnu/libnss_compat-2.15.so 7f12fe561000-7f12fe562000 r--p 00007000 ca:02 3489985 /lib/x86_64-linux-gnu/libnss_compat-2.15.so 7f12fe562000-7f12fe563000 rw-p 00008000 ca:02 3489985 /lib/x86_64-linux-gnu/libnss_compat-2.15.so 7f12fe563000-7f12fe565000 r-xp 00000000 ca:02 3489886 /lib/x86_64-linux-gnu/libdl-2.15.so 7f12fe565000-7f12fe765000 ---p 00002000 ca:02 3489886 /lib/x86_64-linux-gnu/libdl-2.15.so 7f12fe765000-7f12fe766000 r--p 00002000 ca:02 3489886 /lib/x86_64-linux-gnu/libdl-2.15.so 7f12fe766000-7f12fe767000 rw-p 00003000 ca:02 3489886 /lib/x86_64-linux-gnu/libdl-2.15.so 7f12fe767000-7f12fe91c000 r-xp 00000000 ca:02 3489888 /lib/x86_64-linux-gnu/libc-2.15.so 7f12fe91c000-7f12feb1b000 ---p 001b5000 ca:02 3489888 /lib/x86_64-linux-gnu/libc-2.15.so 7f12feb1b000-7f12feb1f000 r--p 001b4000 ca:02 3489888 /lib/x86_64-linux-gnu/libc-2.15.so 7f12feb1f000-7f12feb21000 rw-p 001b8000 ca:02 3489888 /lib/x86_64-linux-gnu/libc-2.15.so 7f12feb21000-7f12feb26000 rw-p 00000000 00:00 0 7f12feb26000-7f12feb2f000 r-xp 00000000 ca:02 3489983 /lib/x86_64-linux-gnu/libcrypt-2.15.so 7f12feb2f000-7f12fed2f000 ---p 00009000 ca:02 3489983 /lib/x86_64-linux-gnu/libcrypt-2.15.so 7f12fed2f000-7f12fed30000 r--p 00009000 ca:02 3489983 /lib/x86_64-linux-gnu/libcrypt-2.15.so 7f12fed30000-7f12fed31000 rw-p 0000a000 ca:02 3489983 /lib/x86_64-linux-gnu/libcrypt-2.15.so 7f12fed31000-7f12fed5f000 rw-p 00000000 00:00 0 7f12fed5f000-7f12fef10000 r-xp 00000000 ca:02 3489831 /lib/x86_64-linux-gnu/libcrypto.so.1.0.0 7f12fef10000-7f12ff110000 ---p 001b1000 ca:02 3489831 /lib/x86_64-linux-gnu/libcrypto.so.1.0.0 7f12ff110000-7f12ff12b000 r--p 001b1000 ca:02 3489831 /lib/x86_64-linux-gnu/libcrypto.so.1.0.0 7f12ff12b000-7f12ff136000 rw-p 001cc000 ca:02 3489831 /lib/x86_64-linux-gnu/libcrypto.so.1.0.0 7f12ff136000-7f12ff13a000 rw-p 00000000 00:00 0 7f12ff13a000-7f12ff150000 r-xp 00000000 ca:02 3490020 /lib/x86_64-linux-gnu/libz.so.1.2.3.4 7f12ff150000-7f12ff34f000 ---p 00016000 ca:02 3490020 /lib/x86_64-linux-gnu/libz.so.1.2.3.4 7f12ff34f000-7f12ff350000 r--p 00015000 ca:02 3490020 /lib/x86_64-linux-gnu/libz.so.1.2.3.4Connection to stageserver.dockphp.com closed. After some debugging, I was able to narrow it down to a few things. For some reason the sshd daemon is running as root:www-data (apache user) instead of root. My ftp connection works but ssh over terminal fails. I have no idea whether it is getting caused due to suPHP or not (because that is the only place where user permission's etc. change). I really need to narrow it down and fix it asap. Thanks a lot!

  Read the article

• List of Commonly Used Value Types in XNA Games

  - by Michael B. McLaughlin

  Most XNA programmers are concerned about generating garbage. More specifically about allocating GC-managed memory (GC stands for “garbage collector” and is both the name of the class that provides access to the garbage collector and an acronym for the garbage collector (as a concept) itself). Two of the major target platforms for XNA (Windows Phone 7 and Xbox 360) use variants of the .NET Compact Framework. On both variants, the GC runs under various circumstances (Windows Phone 7 and Xbox 360). Of concern to XNA programmers is the fact that it runs automatically after a fixed amount of GC-managed memory has been allocated (currently 1MB on both systems). Many beginning XNA programmers are unaware of what constitutes GC-managed memory, though. So here’s a quick overview. In .NET, there are two different “types” of types: value types and reference types. Only reference types are managed by the garbage collector. Value types are not managed by the garbage collector and are instead managed in other ways that are implementation dependent. For purposes of XNA programming, the important point is that they are not managed by the GC and thus do not, by themselves, increment that internal 1 MB allocation counter. (n.b. Structs are value types. If you have a struct that has a reference type as a member, then that reference type, when instantiated, will still be allocated in the GC-managed memory and will thus count against the 1 MB allocation counter. Putting it in a struct doesn’t change the fact that it gets allocated on the GC heap, but the struct itself is created outside of the GC’s purview). Both value types and reference types use the keyword ‘new’ to allocate a new instance of them. Sometimes this keyword is hidden by a method which creates new instances for you, e.g. XmlReader.Create. But the important thing to determine is whether or not you are dealing with a value types or a reference type. If it’s a value type, you can use the ‘new’ keyword to allocate new instances of that type without incrementing the GC allocation counter (except as above where it’s a struct with a reference type in it that is allocated by the constructor, but there are no .NET Framework or XNA Framework value types that do this so it would have to be a struct you created or that was in some third-party library you were using for that to even become an issue). The following is a list of most all of value types you are likely to use in a generic XNA game: AudioCategory (used with XACT; not available on WP7) AvatarExpression (Xbox 360 only, but exposed on Windows to ease Xbox development) bool BoundingBox BoundingSphere byte char Color DateTime decimal double any enum (System.Enum itself is a class, but all enums are value types such that there are no GC allocations for enums) float GamePadButtons GamePadCapabilities GamePadDPad GamePadState GamePadThumbSticks GamePadTriggers GestureSample int IntPtr (rarely but occasionally used in XNA) KeyboardState long Matrix MouseState nullable structs (anytime you see, e.g. int? something, that ‘?’ denotes a nullable struct, also called a nullable type) Plane Point Quaternion Ray Rectangle RenderTargetBinding sbyte (though I’ve never seen it used since most people would just use a short) short TimeSpan TouchCollection TouchLocation TouchPanelCapabilities uint ulong ushort Vector2 Vector3 Vector4 VertexBufferBinding VertexElement VertexPositionColor VertexPositionColorTexture VertexPositionNormalTexture VertexPositionTexture Viewport So there you have it. That’s not quite a complete list, mind you. For example: There are various structs in the .NET framework you might make use of. I left out everything from the Microsoft.Xna.Framework.Graphics.PackedVector namespace, since everything in there ventures into the realm of advanced XNA programming anyway (n.b. every single instantiable thing in that namespace is a struct and thus a value type; there are also two interfaces but interfaces cannot be instantiated at all and thus don’t figure in to this discussion). There are so many enums you’re likely to use (PlayerIndex, SpriteSortMode, SpriteEffects, SurfaceFormat, etc.) that including them would’ve flooded the list and reduced its utility. So I went with “any enum” and trust that you can figure out what the enums are (and it’s rare to use ‘new’ with an enum anyway). That list also doesn’t include any of the pre-defined static instances of some of the classes (e.g. BlendState.AlphaBlend, BlendState.Opaque, etc.) which are already allocated such that using them doesn’t cause any new allocations and therefore doesn’t increase that 1 MB counter. That list also has a few misleading things. VertexElement, VertexPositionColor, and all the other vertex types are structs. But you’re only likely to ever use them as an array (for use with VertexBuffer or DynamicVertexBuffer), and all arrays are reference types (even arrays of value types such as VertexPositionColor[ ] or int[ ]). * So that’s it for now. The note below may be a bit confusing (it deals with how the GC works and how arrays are managed in .NET). If so, you can probably safely ignore it for now but feel free to ask any questions regardless. * Arrays of value types (where the value type doesn’t contain any reference type members) are much faster for the GC to examine than arrays of reference types, so there is a definite benefit to using arrays of value types where it makes sense. But creating arrays of value types does cause the GC’s allocation counter to increase. Indeed, allocating a large array of a value type is one of the quickest ways to increment the allocation counter since a .NET array is a sequential block of memory. An array of reference types is just a sequential block of references (typically 4 bytes each) while an array of value types is a sequential block of instances of that type. So for an array of Vector3s it would be 12 bytes each since each float is 4 bytes and there are 3 in a Vector3; for an array of VertexPositionNormalTexture structs it would typically be 32 bytes each since it has two Vector3s and a Vector2. (Note that there are a few additional bytes taken up in the creation of an array, typically 12 but sometimes 16 or possibly even more, which depend on the implementation details of the array type on the particular platform the code is running on).

  Read the article

• Tuning Red Gate: #4 of Some

  - by Grant Fritchey

  First time connecting to these servers directly (keys to the kingdom, bwa-ha-ha-ha. oh, excuse me), so I'm going to take a look at the server properties, just to see if there are any issues there. Max memory is set, cool, first possible silly mistake clear. In fact, these look to be nicely set up. Oh, I'd like to see the ANSI Standards set by default, but it's not a big deal. The default location for database data is the F:\ drive, where I saw all the activity last time. Cool, the people maintaining the servers in our company listen, parallelism threshold is set to 35 and optimize for ad hoc is enabled. No shocks, no surprises. The basic setup is appropriate. On to the problem database. Nothing wrong in the properties. The database is in SIMPLE recovery, but I think it's a reporting system, so no worries there. Again, I'd prefer to see the ANSI settings for connections, but that's the worst thing I can see. Time to look at the queries, tables, indexes and statistics because all the information I've collected over the last several days suggests that we're not looking at a systemic problem (except possibly not enough memory), but at the traditional tuning issues. I just want to note that, I started looking at the system, not the queries. So should you when tuning your environment. I know, from the data collected through SQL Monitor, what my top poor performing queries are, and the most frequently called, etc. I'm starting with the most frequently called. I'm going to get the execution plan for this thing out of the cache (although, with the cache dumping constantly, I might not get it). And it's not there. Called 1.3 million times over the last 3 days, but it's not in cache. Wow. OK. I'll see what's in cache for this database: SELECT  deqs.creation_time,         deqs.execution_count,         deqs.max_logical_reads,         deqs.max_elapsed_time,         deqs.total_logical_reads,         deqs.total_elapsed_time,         deqp.query_plan,         SUBSTRING(dest.text, (deqs.statement_start_offset / 2) + 1,                   (deqs.statement_end_offset - deqs.statement_start_offset) / 2                   + 1) AS QueryStatement FROM    sys.dm_exec_query_stats AS deqs         CROSS APPLY sys.dm_exec_sql_text(deqs.sql_handle) AS dest         CROSS APPLY sys.dm_exec_query_plan(deqs.plan_handle) AS deqp WHERE   dest.dbid = DB_ID('Warehouse') AND deqs.statement_end_offset > 0 AND deqs.statement_start_offset > 0 ORDER BY deqs.max_logical_reads DESC ; And looking at the most expensive operation, we have our first bad boy: Multiple table scans against very large sets of data and a sort operation. a sort operation? It's an insert. Oh, I see, the table is a heap, so it's doing an insert, then sorting the data and then inserting into the primary key. First question, why isn't this a clustered index? Let's look at some more of the queries. The next one is deceiving. Here's the query plan: You're thinking to yourself, what's the big deal? Well, what if I told you that this thing had 8036318 reads? I know, you're looking at skinny little pipes. Know why? Table variable. Estimated number of rows = 1. Actual number of rows. well, I'm betting several more than one considering it's read 8 MILLION pages off the disk in a single execution. We have a serious and real tuning candidate. Oh, and I missed this, it's loading the table variable from a user defined function. Let me check, let me check. YES! A multi-statement table valued user defined function. And another tuning opportunity. This one's a beauty, seriously. Did I also mention that they're doing a hash against all the columns in the physical table. I'm sure that won't lead to scans of a 500,000 row table, no, not at all. OK. I lied. Of course it is. At least it's on the top part of the Loop which means the scan is only executed once. I just did a cursory check on the next several poor performers. all calling the UDF. I think I found a big tuning opportunity. At this point, I'm typing up internal emails for the company. Someone just had their baby called ugly. In addition to a series of suggested changes that we need to implement, I'm also apologizing for being such an unkind monster as to question whether that third eye & those flippers belong on such an otherwise lovely child.

  Read the article

• Memory Efficient Windows SOA Server

  - by Antony Reynolds

  Installing a Memory Efficient SOA Suite 11.1.1.6 on Windows Server Well 11.1.1.6 is now available for download so I thought I would build a Windows Server environment to run it.  I will minimize the memory footprint of the installation by putting all functionality into the Admin Server of the SOA Suite domain. Required Software 64-bit JDK SOA Suite If you want 64-bit then choose “Generic” rather than “Microsoft Windows 32bit JVM” or “Linux 32bit JVM” This has links to all the required software. If you choose “Generic” then the Repository Creation Utility link does not show, you still need this so change the platform to “Microsoft Windows 32bit JVM” or “Linux 32bit JVM” to get the software. Similarly if you need a database then you need to change the platform to get the link to XE for Windows or Linux. If possible I recommend installing a 64-bit JDK as this allows you to assign more memory to individual JVMs. Windows XE will work, but it is better if you can use a full Oracle database because of the limitations on XE that sometimes cause it to run out of space with large or multiple SOA deployments. Installation Steps The following flow chart outlines the steps required in installing and configuring SOA Suite. The steps in the diagram are explained below. 64-bit? Is a 64-bit installation required?  The Windows & Linux installers will install 32-bit versions of the Sun JDK and JRockit.  A separate JDK must be installed for 64-bit. Install 64-bit JDK The 64-bit JDK can be either Hotspot or JRockit.  You can choose either JDK 1.7 or 1.6. Install WebLogic If you are using 64-bit then install WebLogic using “java –jar wls1036_generic.jar”.  Make sure you include Coherence in the installation, the easiest way to do this is to accept the “Typical” installation. SOA Suite Required? If you are not installing SOA Suite then you can jump straight ahead and create a WebLogic domain. Install SOA Suite Run the SOA Suite installer and point it at the existing Middleware Home created for WebLogic.  Note to run the SOA installer on Windows the user must have admin privileges.  I also found that on Windows Server 2008R2 I had to start the installer from a command prompt with administrative privileges, granting it privileges when it ran caused it to ignore the jreLoc parameter. Database Available? Do you have access to a database into which you can install the SOA schema.  SOA Suite requires access to an Oracle database (it is supported on other databases but I would always use an oracle database). Install Database I use an 11gR2 Oracle database to avoid XE limitations.  Make sure that you set the database character set to be unicode (AL32UTF8).  I also disabled the new security settings because they get in the way for a developer database.  Don’t forget to check that number of processes is at least 150 and number of sessions is not set, or is set to at least 200 (in the DB init parameters). Run RCU The SOA Suite database schemas are created by running the Repository Creation Utility.  Install the “SOA and BPM Infrastructure” component to support SOA Suite.  If you keep the schema prefix as “DEV” then the config wizard is easier to complete. Run Config Wizard The Config wizard creates the domain which hosts the WebLogic server instances.  To get a minimum footprint SOA installation choose the “Oracle Enterprise Manager” and “Oracle SOA Suite for developers” products.  All other required products will be automatically selected. The “for developers” installs target the appropriate components at the AdminServer rather than creating a separate managed server to house them.  This reduces the number of JVMs required to run the system and hence the amount of memory required.  This is not suitable for anything other than a developer environment as it mixes the admin and runtime functions together in a single server.  It also takes a long time to load all the required modules, making start up a slow process. If it exists I would recommend running the config wizard found in the “oracle_common/common/bin” directory under the middleware home.  This should have access to all the templates, including SOA. If you also want to run BAM in the same JVM as everything else then you need to “Select Optional Configuration” for “Managed Servers, Clusters and Machines”. To target BAM at the AdminServer delete the “bam_server1” managed server that is created by default.  This will result in BAM being targeted at the AdminServer. Installation Issues I had a few problems when I came to test everything in my mega-JVM. Following applications were not targeted and so I needed to target them at the AdminServer: b2bui composer Healthcare UI FMW Welcome Page Application (11.1.0.0.0) How Memory Efficient is It? On a Windows 2008R2 Server running under VirtualBox I was able to bring up both the 11gR2 database and SOA/BPM/BAM in 3G memory.  I allocated a minimum 512M to the PermGen and a minimum of 1.5G for the heap.  The setting from setSOADomainEnv are shown below: set DEFAULT_MEM_ARGS=-Xms1536m -Xmx2048m set PORT_MEM_ARGS=-Xms1536m -Xmx2048m set DEFAULT_MEM_ARGS=%DEFAULT_MEM_ARGS% -XX:PermSize=512m -XX:MaxPermSize=768m set PORT_MEM_ARGS=%PORT_MEM_ARGS% -XX:PermSize=512m -XX:MaxPermSize=768m I arrived at these numbers by monitoring JVM memory usage in JConsole. Task Manager showed total system memory usage at 2.9G – just below the 3G I allocated to the VM. Performance is not stellar but it runs and I could run JDeveloper alongside it on my 8G laptop, so in that sense it was a result!

  Read the article

• What Counts For a DBA: Simplicity

  - by Louis Davidson

  Too many computer processes do an apparently simple task in a bizarrely complex way. They remind me of this strip by one of my favorite artists: Rube Goldberg. In order to keep the boss from knowing one was late, a process is devised whereby the cuckoo clock kisses a live cuckoo bird, who then pulls a string, which triggers a hat flinging, which in turn lands on a rod that removes a typewriter cover…and so on. We rely on creating automated processes to keep on top of tasks. DBAs have a lot of tasks to perform: backups, performance tuning, data movement, system monitoring, and of course, avoiding being noticed.  Every day, there are many steps to perform to maintain the database infrastructure, including: checking physical structures, re-indexing tables where needed, backing up the databases, checking those backups, running the ETL, and preparing the daily reports and yes, all of these processes have to complete before you can call it a day, and probably before many others have started that same day. Some of these tasks are just naturally complicated on their own. Other tasks become complicated because the database architecture is excessively rigid, and we often discover during “production testing” that certain processes need to be changed because the written requirements barely resembled the actual customer requirements.   Then, with no time to change that rigid structure, we are forced to heap layer upon layer of code onto the problematic processes. Instead of a slight table change and a new index, we end up with 4 new ETL processes, 20 temp tables, 30 extra queries, and 1000 lines of SQL code.  Report writers then need to build reports and make magical numbers appear from those toxic data structures that are overly complex and probably filled with inconsistent data. What starts out as a collection of fairly simple tasks turns into a Goldbergian nightmare of daily processes that are likely to cause your dinner to be interrupted by the smartphone doing the vibration dance that signifies trouble at the mill. So what to do? Well, if it is at all possible, simplify the problem by either going into the code and refactoring the complex code to simple, or taking all of the processes and simplifying them into small, independent, easily-tested steps.  The former approach usually requires an agreement on changing underlying structures that requires countless mind-numbing meetings; while the latter can generally be done to any complex process without the same frustration or anger, though it will still leave you with lots of steps to complete, the ability to test each step independently will definitely increase the quality of the overall process (and with each step reporting status back, finding an actual problem within the process will be definitely less unpleasant.) We all know the principle behind simplifying a sequence of processes because we learned it in math classes in our early years of attending school, starting with elementary school. In my 4 years (ok, 9 years) of undergraduate work, I remember pretty much one thing from my many math classes that I apply daily to my career as a data architect, data programmer, and as an occasional indentured DBA: “show your work”. This process of showing your work was my first lesson in simplification. Each step in the process was in fact, far simpler than the entire process.  When you were working an equation that took both sides of 4 sheets of paper, showing your work was important because the teacher could see every step, judge it, and mark it accordingly.  So often I would make an error in the first few lines of a problem which meant that the rest of the work was actually moving me closer to a very wrong answer, no matter how correct the math was in the subsequent steps. Yet, when I got my grade back, I would sometimes be pleasantly surprised. I passed, yet missed every problem on the test. But why? While I got the fact that 1+1=2 wrong in every problem, the teacher could see that I was using the right process. In a computer process, the process is very similar. We take complex processes, show our work by storing intermediate values, and test each step independently. When a process has 100 steps, each step becomes a simple step that is tested and verified, such that there will be 100 places where data is stored, validated, and can be checked off as complete. If you get step 1 of 100 wrong, you can fix it and be confident (that if you did your job of testing the other steps better than the one you had to repair,) that the rest of the process works. If you have 100 steps, and store the state of the process exactly once, the resulting testable chunk of code will be far more complex and finding the error will require checking all 100 steps as one, and usually it would be easier to find a specific needle in a stack of similarly shaped needles.  The goal is to strive for simplicity either in the solution, or at least by simplifying every process down to as many, independent, testable, simple tasks as possible.  For the tasks that really can’t be done completely independently, minimally take those tasks and break them down into simpler steps that can be tested independently.  Like working out division problems longhand, have each step of the larger problem verified and tested.

  Read the article

• The Sound of Two Toilets Flushing: Constructive Criticism for Virgin Atlantic Complaints Department

  - by Geertjan

  I recently had the experience of flying from London to Johannesburg and back with Virgin Atlantic. The good news was that it was the cheapest flight available and that the take off and landing were absolutely perfect. Hence I really have no reason to complain. Instead, I'd like to offer some constructive criticism which hopefully Richard Branson will find sometime while googling his name. Or maybe someone from the Virgin Atlantic Complaints Department will find it, whatever, just want to put this information out there. Arrangement of restroom facilities. Maybe next time you design an airplane, consider not putting your toilets at a right angle right next to your rows of seats. Being able to reach, without even needing to stretch your arm, from your seat to close, yet again, a toilet door that someone, someone obviously sitting very far from the toilets, carelessly forgot to close is not an indicator of quality interior design. Have you noticed how all other airplanes have their toilets in a cubicle separated from the rows of seats? On those airplanes, people sitting in the seats near the toilets are not constantly being woken up throughout the night whenever someone enters/exits the toilet, whenever the light in the toilet is suddenly switched on, and whenever one of the toilets flushes. Bonus points for Virgin Atlantic passengers in the seats adjoining the toilets is when multiple toilets are flushed simultaneously and multiple passengers enter/exit them at the same time, a bit like an unasked for low budget musical of suddenly illuminated grumpy people in crumpled clothes. What joy that brings at 3 AM is hard to describe. Seats with extra leg room. You know how other airplanes have the seats with the extra leg room? You know what those seats tend to have? Extra leg room. It's really interesting how Virgin Atlantic's seats with extra leg room actually have no extra leg room at all. It should have been a give away, the fact that these special seats are found in the same rows as the standard seats, rather than on the cusp of real glory which is where most airlines put their extra leg room seats, with the only actual difference being that they have a slightly different color. Had you called them "seats with a different color" (i.e., almost not quite green, rather than something vaguely hinting at blue), at least I'd have known what I was getting. Picture the joy at 3 AM, rudely awakened from nightmarish slumber, partly grateful to have been released from a grayish dream of faceless zombies resembling one or two of those in a recent toilet line, by multiple adjoining toilets flushing simultaneously, while you're sitting in a seat with extra leg room that has exactly as much leg room as the seats in neighboring rows. You then have a choice of things to be sincerely annoyed about. Food from the '80's. In the '80's, airplane food came in soggy containers and even breakfast, the most important meal of the day, was a sad heap of vaguely gray colors. The culinary highlight tended to be a squashed tomato, which must have been mashed to a pulp with a brick prior to being regurgitated by a small furry animal, and there was also always a piece of immensely horrid pumpkin, as well as a slice of spongy something you'd never seen before. Sausages and mash at 6 AM on an airplane was always a heavy lump of horribleness. Thankfully, all airlines throughout the world changed from this puke inducing strategy around 1987 sometime. Not Virgin Atlantic, of course. The fatty sausages and mash are still there, bringing you flashbacks to Duran Duran, which is what you were listening to (on your walkman) the last time you saw it in an airplane. Even the golden oldie "squashed tomato attached by slime to three wet peas" is on the menu. How wonderful to have all this in a cramped seat with a long row of early morning bleariness lined up for the toilets, right at your side, bumping into your elbow, groggily, one by one, one after another, more and more, fumble-open-door-silence-flush-fumble-open-door, and on and on, while you tentatively push your fork through a soggy pile of colorless mush, fighting the urge to throw up on the stinky socks of whatever nightmarish zombie is bumping into your elbow at the time. But, then again, the plane landed without a hitch, in fact, extremely smoothly, so I'm certainly not blaming the pilots.

  Read the article

• Profiling Startup Of VS2012 &ndash; YourKit Profiler

  - by Alois Kraus

  The YourKit (v7.0.5) profiler is interesting in terms of price (79€ single place license, 409€ + 1 year support and upgrades) and feature set. You do get a performance and memory profiler in one package for which you normally need also to pay extra from the other vendors. As an interesting side note the profiler UI is written in Java because they do also sell Java profilers with the same feature set. To get all methods of a VS startup you need first to configure it to include System* in the profiled methods and you need to configure * to measure wall clock time. By default it does record only CPU times which allows you to optimize CPU hungry operations. But you will never see a Thread.Sleep(10000) in the profiler blocking the UI in this mode. It can profile as all others processes started from within the profiler but it can also profile the next or all started processes. As usual it can profile in sampling and tracing mode. But since it is a memory profiler as well it does by default also record all object allocations > 1MB. With allocation recording enabled VS2012 did crash but without allocation recording there were no problems. The CPU tab contains the time line of the application and when you click in the graph you the call stacks of all threads at this time. This is really a nice feature. When you select a time region you the CPU Usage estimation for this time window. I have seen many applications consuming 100% CPU only because they did create garbage like crazy. For this is the Garbage Collection tab interesting in conjunction with a time range. This view is like the CPU table only that the CPU graph (green) is missing. All relevant information except for GCs/s is already visible in the CPU tab. Very handy to pinpoint excessive GC or CPU bound issues. The Threads tab does show the thread names and their lifetime. This is useful to see thread interactions or which thread is hottest in terms of CPU consumption. On the CPU tab the call tree does exist in a merged and thread specific view. When you click on a method you get below a list of all called methods. There you can sort for methods with a high own time which are worth optimizing. In the Method List you can select which scope you want to see. Back Traces are the methods which did call you. Callees ist the list of methods called directly or indirectly by your method as a flat list. This is not a call stack but still very useful to see which methods were slow so you can see the “root” cause quite quickly without the need to click trough long call stacks. The last view Merged Calles is a call stacked view of the previous view. This does help a lot to understand did call each method at run time. You would get the same view with a debugger for one call invocation but here you get the full statistics (invocation count) as well. Since YourKit is also a memory profiler you can directly see which objects you have on your managed heap and which objects do hold most of your precious memory. You can in in the Object Explorer view also examine the contents of your objects (strings or whatsoever) to get a better understanding which objects where potentially allocating this stuff.   YourKit is a very easy to use combined memory and performance profiler in one product. The unbeatable single license price makes it very attractive to straightly buy it. Although it is a Java UI it is very responsive and the memory consumption is considerably lower compared to dotTrace and ANTS profiler. What I do really like is to start the YourKit ui and then start the processes I want to profile as usual. There is no need to alter your own application code to be able to inject a profiler into your new started processes. For performance and memory profiling you can simply select the process you want to investigate from the list of started processes. That's the way I like to use profilers. Just get out of the way and let the application run without any special preparations.   Next: Telerik JustTrace

  Read the article

• Profiling NetBeans 7.0 Beta 2 and Reporting Problems

  - by christopher.jones

  With NetBeans 7.0 recently going into Beta 2 phase, now is the time to test it out properly and report issues. The development team has been squashing bugs, including memory issues with the PHP bundle.There are some great new PHP related features in NetBeans 7.0, so you know you want to try it out.If you identify something wrong with NetBeans, please report it following the guidelines http://wiki.netbeans.org/IssueReportingGuidelinesDepending on the issues, data to attach to the report is mentioned on: http://wiki.netbeans.org/FaqLogMessagesFile and http://wiki.netbeans.org/FaqProfileMeNowIf you have a memory issue then a memory dump would also be useful. Run the jmap tool for this. There is some background information on http://wiki.netbeans.org/FaqMemoryDump. Here's how I used it.First I set my environment to match the JDK used by NetBeans. In my case I am using a nightly build so the JDK is in the configuration file under $HOME/netbeans-dev-201102210501:$ egrep netbeans_jdkhome $HOME/netbeans-dev-201102210501/etc/netbeans.conf netbeans_jdkhome="/home/cjones/src/jdk1.6.0_24" $ export JAVA_HOME=/home/cjones/src/jdk1.6.0_24 $ export PATH=$JAVA_HOME/bin:$PATH Next, I found the correct process number to examine:$ ps -ef | egrep 'netbeans|jdk'cjones   23230     1  0 16:07 ?        00:00:00 /bin/bash /home/cjones/netbeans-cjones   23438 23230  2 16:07 ?        00:00:09 /home/cjones/src/jdk1.6.0_24/binFinally I used the parent JDK process as the jmap argument:$ jmap -histo:live 23438 num     #instances         #bytes  class name----------------------------------------------   1:         12075        9028656  [I   2:         49535        6581920  <constMethodKlass>   3:         49535        3964128  <methodKlass>   4:         80256        3840776  <symbolKlass>   5:         36093        3635336  [C   6:          5095        3341312  <constantPoolKlass>   7:          5095        2486016  <instanceKlassKlass>   8:          4325        1961432  <constantPoolCacheKlass>   9:         18729        1763976  [B  10:         59952        1438848  java.util.HashMap$Entry  . . .This histogram memory report will help identify the kind of memory issues you are seeing. It may not be as complete as an often tens of megabyte jmap -dump:live,file=/tmp/nbheap.log 23438 heap dump, but is much more easily attached to a bug report.If you want to keep up to date with NetBeans, nightly builds are at: http://bits.netbeans.org/download/trunk/nightly/latest/zip/

  Read the article

• Windows 7 .NET 3.5.1 - 2.0 Slightly Corrupted, How to Repair?

  - by Quinxy von Besiex

  My Windows 7 included .NET installation (3.5 to 2.0) appears very slightly and particularly corrupted and I am trying to fix it without reinstalling Windows or trying to revert to backups. Everything was working and then my hard drive started corrupting a few files and checkdisk found bad clusters so I imaged the drive to a new one. As soon as I booted on the new drive everything worked except programs which call the System.Net.NetworkInformation methods within .NET 3.5 to 2.0 (like Ping() and IsNetworkAvailable()), which immediately crash the app in which the calls are (those calls in .NET 4.0 works fine). Those methods are found inside System.dll, and I assume call native methods which I believe are inside winnsi.dll or iphlpapi.dll or something else (I've not found this yet); I assume it calls native methods because the exception which causes the crash is Fatal Execution Engine Error which people mention is usually related to calling native methods and marshaling data between them. A huge clue about the culprit is likely found in the fact that when I launch the exact same crashing application through a code profiler (which executes the exe and captures stats on which methods took the longest) the app works fine, no crash at all! How could running it within the profiler work and running it outside not work? That seems the key to the mystery. I've used procmon to catch all the registry, filesystem, and network events from the crashing execution and the profiler-run successful execution and compared the two outputs but didn't learn much (I see the moment at which the non-profiled app crashes, but up until then they behave the same, loaded the same modules, ). The only big difference seems to be that at the moment before the app crash the profiler-executed code creates 4-6 new threads and the directly executed code only creates 1-2. I have diffed the files/directories which seemed most relevant (the .NET stuff under Windows and Program Files) pre- and post- disk trouble and seen no changes where I didn't expect any (no obvious file corruption). I have diffed the software and system registry hives pre- and post- disk trouble and seen no changes which seemed relevant. I have created a new user account and cleaned up any environment variables in case environment was related. No change. I did "sfc /scannow" and it found no integrity problems. I tried "ngen update" to regenerate pre-compiled code in case I missed something that might be damaged and nothing changed. I assume I need to repair my .NET installation but because Windows 7 included .NET 3.5 - 2.0 you can't just re-run a .NET installer to redo it. I do not have access to the Windows disks to try to re-install Windows over itself (the computer has a recovery partition but it is unusable); also the drive uses a whole-disk encryption solution and re-installing would be difficult. I absolutely do not want to start from scratch here and install a fresh Windows, reinstall dozens of software packages, try and remember dozens of development-related customizations/etc. Given all that... does anyone have any helpful advice? I need .NET 3.5 - 2.0 working as I am a developer and need to build and test against it. Thanks! Quinxy

  Read the article

• MySQL 5.5 (Percona) assertion failure log.. what would cause this?

  - by Tom Geee

  256GB, 64 Core , AMD running Ubuntu 12.04 with Percona MySQL 5.5.28. Below is the assertion failure. We just had a second assertion failure (different "in file", position, etc) while running a large set of inserts. After the first failure, MySQL restarted after a reboot only - after continuously looping on the same error after trying to recover. I decided to do a mysqlcheck with -o for optimize. Since these are all Innodb tables (very large tables, 60+GB) this would do an alter table on all tables. In the middle of this , the below assertion failure happened again: 121115 22:30:31 InnoDB: Assertion failure in thread 140086589445888 in file btr0pcur.c line 452 InnoDB: Failing assertion: btr_page_get_prev(next_page, mtr) == buf_block_get_page_no(btr_pcur_get_block(cursor)) InnoDB: We intentionally generate a memory trap. InnoDB: Submit a detailed bug report to http://bugs.mysql.com. InnoDB: If you get repeated assertion failures or crashes, even InnoDB: immediately after the mysqld startup, there may be InnoDB: corruption in the InnoDB tablespace. Please refer to InnoDB: http://dev.mysql.com/doc/refman/5.5/en/forcing-innodb-recovery.html InnoDB: about forcing recovery. 03:30:31 UTC - mysqld got signal 6 ; This could be because you hit a bug. It is also possible that this binary or one of the libraries it was linked against is corrupt, improperly built, or misconfigured. This error can also be caused by malfunctioning hardware. We will try our best to scrape up some info that will hopefully help diagnose the problem, but since we have already crashed, something is definitely wrong and this may fail. Please help us make Percona Server better by reporting any bugs at http://bugs.percona.com/ key_buffer_size=536870912 read_buffer_size=131072 max_used_connections=404 max_threads=500 thread_count=90 connection_count=90 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 1618416 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x14edeb710 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... stack_bottom = 7f687366ce80 thread_stack 0x30000 /usr/sbin/mysqld(my_print_stacktrace+0x2e)[0x7b52ee] /usr/sbin/mysqld(handle_fatal_signal+0x484)[0x68f024] /lib/x86_64-linux-gnu/libpthread.so.0(+0xfcb0)[0x7f9cbb23fcb0] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x35)[0x7f9cbaea6425] /lib/x86_64-linux-gnu/libc.so.6(abort+0x17b)[0x7f9cbaea9b8b] /usr/sbin/mysqld[0x858463] /usr/sbin/mysqld[0x804513] /usr/sbin/mysqld[0x808432] /usr/sbin/mysqld[0x7db8bf] /usr/sbin/mysqld(_Z13rr_sequentialP11READ_RECORD+0x1d)[0x755aed] /usr/sbin/mysqld(_Z17mysql_alter_tableP3THDPcS1_P24st_ha_create_informationP10TABLE_LISTP10Alter_infojP8st_orderb+0x216b)[0x60399b] /usr/sbin/mysqld(_Z20mysql_recreate_tableP3THDP10TABLE_LIST+0x166)[0x604bd6] /usr/sbin/mysqld[0x647da1] /usr/sbin/mysqld(_ZN24Optimize_table_statement7executeEP3THD+0xde)[0x64891e] /usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0x1168)[0x59b558] /usr/sbin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x30c)[0x5a132c] /usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x1620)[0x5a2a00] /usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0x14f)[0x63ce6f] /usr/sbin/mysqld(handle_one_connection+0x51)[0x63cf31] /lib/x86_64-linux-gnu/libpthread.so.0(+0x7e9a)[0x7f9cbb237e9a] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f9cbaf63cbd] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (7f6300004b60): is an invalid pointer Connection ID (thread ID): 876 Status: NOT_KILLED You may download the Percona Server operations manual by visiting http://www.percona.com/software/percona-server/. You may find information in the manual which will help you identify the cause of the crash. 121115 22:31:07 [Note] Plugin 'FEDERATED' is disabled. 121115 22:31:07 InnoDB: The InnoDB memory heap is disabled 121115 22:31:07 InnoDB: Mutexes and rw_locks use GCC atomic builtins .. Then it recovered , without a reboot this time. from the log, what would cause this? I am currently running a dump to see if the problem resurfaces. edit: data partition is all in / since this is a hosted, defaulted file system unfortunately: Filesystem Size Used Avail Use% Mounted on /dev/vda3 742G 445G 260G 64% / udev 121G 4.0K 121G 1% /dev tmpfs 49G 248K 49G 1% /run none 5.0M 0 5.0M 0% /run/lock none 121G 0 121G 0% /run/shm /dev/vda1 99M 54M 40M 58% /boot my.cnf: [client] port = 3306 socket = /var/run/mysqld/mysqld.sock [mysqld_safe] socket = /var/run/mysqld/mysqld.sock nice = 0 [mysqld] skip-name-resolve innodb_file_per_table default_storage_engine=InnoDB user = mysql socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /data/mysql tmpdir = /tmp skip-external-locking key_buffer = 512M max_allowed_packet = 128M thread_stack = 192K thread_cache_size = 64 myisam-recover = BACKUP max_connections = 500 table_cache = 812 table_definition_cache = 812 #query_cache_limit = 4M #query_cache_size = 512M join_buffer_size = 512K innodb_additional_mem_pool_size = 20M innodb_buffer_pool_size = 196G #innodb_file_io_threads = 4 #innodb_thread_concurrency = 12 innodb_flush_log_at_trx_commit = 1 innodb_log_buffer_size = 8M innodb_log_file_size = 1024M innodb_log_files_in_group = 2 innodb_max_dirty_pages_pct = 90 innodb_lock_wait_timeout = 120 log_error = /var/log/mysql/error.log long_query_time = 5 slow_query_log = 1 slow_query_log_file = /var/log/mysql/slowlog.log [mysqldump] quick quote-names max_allowed_packet = 16M [mysql] [isamchk] key_buffer = 16M

  Read the article

• Windows 7 is stuck at "Starting Windows" when I attempt to boot computer

  - by Eli

  Basically, whenever I turn on my computer, it gets to the Starting Windows phase and just stays there. The startup animation still plays, yet it gets nowhere. I have tried booting into safe mode, however it gets stuck at loading CLASSPNP.SYS. It then freezes there and doesn't continue booting. I have tried booting into recovery mode from the hard drive, and it freezes after displaying the background image. I have tried booting from a recovery CD, which works, and I was able to use system restore. However, using system restore did not fix it, and it still is stuck at the Starting Windows screen. I have tried booting a Windows CD (Windows 8 Retail Installer) to see if I could upgrade it to fix this issue, however that froze at a blank screen after it got past the boot logo. I have tried changing around the BIOS settings (including resetting), to no avail. I have tried re-plugging the internal PSU cables (this is a custom-built desktop), yet this has changed nothing. I can boot into a loopback Ubuntu install on the same drive, which works fine, other than the fact that it has issues with some of the USB ports and the network card. This system has worked fine for the past few months, completely stable, and nothing in the configuration has changed before this error started happening. Startup Repair on the Windows recovery CD doesn't find any issues. Unplugging my secondary hard drive or swapping around memory doesn't change anything. The hard drive itself is fine, it hasn't shown any signs of failure and once again, boots my other OS fine. If anyone could help with this, that would be great. I can't seem to find any possible solution to this. If it makes any difference, my system specs are as follows: AMD FX-8320 Gigabyte GA-970A-D3 4GB of DDR3 Radeon HD 6870 550w PSU I'd like to not have to reinstall Windows, for I have more than a terabyte of data that I would have to back up if that becomes the only option. EDIT: I have since tried the following: Tried the solution involving restoring files from RegBackup, which changed nothing. Tried testing everything with Hiren's boot CD, everything comes back as fine. Tried disabling everything unnecessary in the BIOS and unplugging everything unneeded, it still hangs. Tried swapping out every possible combination of RAM, it still has the same result. The RAM is not at fault it seems Tried every GPU I own (which is many!) and it still hangs at the exact same place. Tried minimizing the power consumption as much as possible, even using an old PCI graphics card. It still hangs at the same place in the same way, signifying that it's not the PSU at fault. Tried resetting the BIOS again, still nothing. Tried every possible combination of BIOS options, even downclocking everything, it still hangs in the same spot. Tried upgrading the BIOS from version FB to FD, which changed nothing. Based on this, I would conclude the motherboard to be at fault. Are there any other possibilities? I don't want to spend $150 for a new motherboard. EDIT 2: This is what it gets stuck at when I try to boot into safe mode: Note the slight graphical corruption at the top of the screen. No matter how I set up the system, this seems to be there. In addition, either it has stopped booting into safe mode now, or it takes upwards of 2+ hours, and I haven't left it running for that long.

  Read the article

• Win a place at a SQL Server Masterclass with Kimberly Tripp and Paul Randal

  - by Testas

  The top things YOU need to know about managing SQL Server - in one place, on one day - presented by two of the best SQL Server industry trainers!And you could be there courtesy of UK SQL Server User Group and SQL Server Magazine! This week the UK SQL Server User Group will provide you with details of how to win a place at this must see seminar   You can also register for the seminar yourself at:www.regonline.co.uk/kimtrippsql More information about the seminar   Where: Radisson Edwardian Heathrow Hotel, London When: Thursday 17th June 2010 This one-day MasterClass will focus on many of the top issues companies face when implementing and maintaining a SQL Server-based solution. In the case where a company has no dedicated DBA, IT managers sometimes struggle to keep the data tier performing well and the data available. This can be especially troublesome when the development team is unfamiliar with the affect application design choices have on database performance. The Microsoft SQL Server MasterClass 2010 is presented by Paul S. Randal and Kimberly L. Tripp, two of the most experienced and respected people in the SQL Server world. Together they have over 30 years combined experience working with SQL Server in the field, and on the SQL Server product team itself. This is a unique opportunity to hear them present at a UK event which will:·         Debunk many of the ingrained misconceptions around SQL Server's behaviour   ·         Show you disaster recovery techniques critical to preserving your company's life-blood - the data   ·         Explain how a common application design pattern can wreak havoc in the database ·         Walk through the top-10 points to follow around operations and maintenance for a well-performing and available data tier! Please Note: Agenda may be subject to changeSessions AbstractsKEYNOTE: Bridging the Gap Between Development and Production  Applications are commonly developed with little regard for how design choices will affect performance in production. This is often because developers don't realize the implications of their design on how SQL Server will be able to handle a high workload (e.g. blocking, fragmentation) and/or because there's no full-time trained DBA that can recognize production problems and help educate developers. The keynote sets the stage for the rest of the day. Discussing some of the issues that can arise, explaining how some can be avoided and highlighting some of the features in SQL 2008 that can help developers and DBAs make better use of SQL Server, and troubleshoot when things go wrong.  SESSION ONE: SQL Server MythbustersIt's amazing how many myths and misconceptions have sprung up and persisted over the years about SQL Server - after many years helping people out on forums, newsgroups, and customer engagements, Paul and Kimberly have heard it all. Are there really non-logged operations? Can interrupting shrinks or rebuilds cause corruption? Can you override the server's MAXDOP setting? Will the server always do a table-scan to get a row count? Many myths lead to poor design choices and inappropriate maintenance practices so these are just a few of many, many myths that Paul and Kimberly will debunk in this fast-paced session on how SQL Server operates and should be managed and maintained. SESSION TWO: Database Recovery Techniques Demo-Fest Even if a company has a disaster recovery strategy in place, they need to practice to make sure that the plan will work when a disaster does strike. In this fast-paced demo session Paul and Kimberly will repeatedly do nasty things to databases and then show how they are recovered - demonstrating many techniques that can be used in production for disaster recovery. Not for the faint-hearted! SESSION THREE: GUIDs: Use, Abuse, and How To Move Forward Since the addition of the GUID (Microsoft’s implementation of the UUID), my life as a consultant and "tuner" has been busy. I’ve seen databases designed with GUID keys run fairly well with small workloads but completely fall over and fail because they just cannot scale. And, I know why GUIDs are chosen - it simplifies the handling of parent/child rows in your batches so you can reduce round-trips or avoid dealing with identity values. And, yes, sometimes it's even for distributed databases and/or security that GUIDs are chosen. I'm not entirely against ever using a GUID but overusing and abusing GUIDs just has to be stopped! Please, please, please let me give you better solutions and explanations on how to deal with your parent/child rows, round-trips and clustering keys! SESSION 4: Essential Database MaintenanceIn this session, Paul and Kimberly will run you through their top-ten database maintenance recommendations, with a lot of tips and tricks along the way. These are distilled from almost 30 years combined experience working with SQL Server customers and are geared towards making your databases more performant, more available, and more easily managed (to save you time!). Everything in this session will be practical and applicable to a wide variety of databases. Topics covered include: backups, shrinks, fragmentation, statistics, and much more! Focus will be on 2005 but we'll explain some of the key differences for 2000 and 2008 as well.    Speaker Biographies     Paul S.Randal  Kimberley L. Tripp Paul and Kimberly are a husband-and-wife team who own and run SQLskills.com, a world-renowned SQL Server consulting and training company. They are both SQL Server MVPs and Microsoft Regional Directors, with over 30 years of combined experience on SQL Server. Paul worked on the SQL Server team for nine years in development and management roles, writing many of the DBCC commands, and ultimately with responsibility for core Storage Engine for SQL Server 2008. Paul writes extensively on his blog (SQLskills.com/blogs/Paul) and for TechNet Magazine, for which he is also a Contributing Editor. Kimberly worked on the SQL Server team in the early 1990s as a tester and writer before leaving to found SQLskills and embrace her passion for teaching and consulting. Kimberly has been a staple at worldwide conferences since she first presented at TechEd in 1996, and she blogs at SQLskills.com/blogs/Kimberly. They have written Microsoft whitepapers and books for SQL Server 2000, 2005 and 2008, and are regular, top-rated presenters worldwide on database maintenance, high availability, disaster recovery, performance tuning, and SQL Server internals. Together they teach the SQL MCM certification and throughout Microsoft.In their spare time, they like to find frogfish in remote corners of the world.  

  Read the article

• CodePlex Daily Summary for Thursday, April 08, 2010

  CodePlex Daily Summary for Thursday, April 08, 2010New ProjectsBackUpAnyWhere: BackUpAnyWhereCustomFormbyEndUser: 在项目开发中，经常遇到不同的用户对同一报表有不同要求的情况，有时甚至用户需要从头生成一个报表，在以前可能使用第三方的开发工具来实现。在SQL Server2005中，通过使用Reporting Services可以使最终用户不通过编码，只要了解数据结构就能自行编辑报表。本例使用Adventur...DbExecutor - linq based database executor: IEnumerable based database reader. (linq like primitive sql executor)DeepZoomRenderingPack: A collection of libraries and plug-ins architecture that turns various files (like PDF, PS, etc.) into a "Visual" representation that the DeepZoom ...DotNetNuke Russian Language packs: DNNRussianLP - DotNetNuke Russian Language pack. F# Refactor: Deisgned to bring Code Refactoring capabilities to the F# Language in Visual Studio 2010. Invocando WebService e Site HTTP dinamicamente com HTTPWebRequest C#: Invocando Site HTTP e WebService dinamicamente com HTTPWebRequest Passando o SoapAction e Envelope XML Escrito em C# www.biztalkbrasil.c...Jitbit WYSWYG BBCode Editor: "Jitbit WYSIWYG-BBCode" is a browser-based JavaScript-powered WYSIWYG BBCode editorMRDS Services for Phidgets: MRDS (Microsoft Robotics Developer Studio) Services for Phidgets provides additional services for Phidgets sensors and controllers that are not inc...MSBuild Addin: This tool is a simple addin for VisualStudio 2008 used in association with Microsoft MSBuild. It allows you to run MSBuild directly inside Visual S...NISHIL-BizTalk Custom Eventlog Functiod: While testing our maps at times when it fails we cant trace it because we don’t know what the output of the functiods are. Normally in a single ma...Northest GNSG: Supinfo B3C Paris Northest University project. Galego, Neveu, Simon, Geissmann.Oily: Composite application project for oil parameters. It's developed in C#Outlook.Utility: The MSDN article Outlook Customization for Integrating with Enterprise Applications at http://msdn.microsoft.com/en-us/library/Aa479345 has quite a...Particle Plot Pivot: Scan select particle physics experiment web sites for plots and generate a Pivot display for easy browsing.project tca: project tca - translating chat application. Satisfyr: A new way of performing assertions on tests so that they remain agnostic to the underlying test framework, and leverage .NET built-in lambda syntax.sejce2008: jce se course wiki and projects linksSGB Controls: SGB Controls is a set of standard .net controls that include a number of enhancements to make life easier for the developer. These controls incl...Syringe: Syringe is a lightweight service container and dependency injection library designed for use with ASP.NET MVC2. Supported features: Dependency inj...topicbox: topicboxUr-Index: Ur-Index makes it a lot easier to create onomastic indexes for books in pdf format.VietGeeks ZohoDocApis: Implement .NET Zoho Document Apis library to help developer can intergrate Zoho Docs easy with their websitesWebometrics Dashboard: Webometrics Dashboardwebpress: It is a WebBased CMS and Blog platform.WPF Ink Canvas Toolbar: WPF Ink Canvas Toolbar makes it easy for WPF developers to use pen input in TabletPC or UMPC applications. The WPF InkCanvas control has drawing, e...WS-TMS: WS GISG HTT TMSNew ReleasesBatterySaver: Version 1.0: Fixed battery increase/decrease events not firing Fixed memory corruption error Added working set trimming (used very sparingly) Fixed poorly rende...Chargify.NET: Chargify.NET 0.65: Added in Transactions, Subscription Re-activation, and finally XML documentation (which has been missing in the previous releases).DbExecutor - linq based database executor: DbExecutor ver.1.0.0.1: renameDotNetNuke Russian Language packs: Russian Language Pack for DotNetNuke 04.09.02: Russian Language Pack for DotNetNuke 04.09.02Encrypted Notes: Encrypted Notes 1.6.3: This is the latest version of Encrypted Notes (1.6.3), with general improvements. It has an installer that will create a directory 'CPascoe' in My ...Invocando WebService e Site HTTP dinamicamente com HTTPWebRequest C#: Código projeto CallSiteHTTP: Código escrito em C#.NET 2.0 - VS2005 Contem: Solution completa(código e executável) XML de configuração - Config.xml ...Jitbit WYSWYG BBCode Editor: Main package: Contains the JS-file, CSS-file and a sample.Live Writer Picasa Plugin: Live Writer Picasa Plugin 1.1.0: Changelog Communication with Picasa Web Albums is done directly via HTTP now (v1.0.0 used Google's GData .NET Libraries) The plugin can search fo...MRDS Services for Phidgets: Phidgets for RDS 2008 R3: First Beta Release This ZIP file contains a web page called Readme_CodePlex.html that explains how to install the RDS Phidgets services for RDS 200...MSBuild Addin: MsBuildAddin-v1.0.0: Initial versionMSBuild Addin: MsBuildAddin-v1.0.0-src.zip: Initial versionOutlook.Utility: Outlook.Utility v1: I have used most of the code in previous projects and seems to be quite stable. Of course the point of open sourcing this is so this project is use...Scrum Dashboard: Scrum Dashboard v3 Alpha 1: Scrum Dashboard v3 is targeting .NET 4, TFS 2010 and the brand new Scrum for Team System v3 process templates. Most of the code has been rewritten ...SharePoint Labs: SPLab4004A-FRA-Level100: SPLab4004A-FRA-Level100 This SharePoint Lab will teach you the 4th best practice you should apply when writing code with the SharePoint API. Lab La...SharePoint Labs: SPLab5012A-FRA-Level100: SPLab5012A-FRA-Level100 This SharePoint Lab will teach you how to provision a new welcome page (how to change and rename the default.aspx page) on ...Shweet: SharePoint 2010 Team Messaging built with Pex: Shweet Source Code: Although the latest version pex and moles used with this project is not available, we thought it would be useful to provide a download to the source.Syringe: Syringe 1.0: Features Dependency injection on properties of services in container Dependency injection on constructors of services in container ASP.Net Mvc ...Text to HTML: 0.4.1.0: Cambios de la versiónOptimización del código de exportación reduciendo el código. Cambio en el icono de exportación. Añadido menú Seleccionar t...VsTortoise - a TortoiseSVN add-in for Microsoft Visual Studio: VsTortoise Build 23: Build 23 Fix: Executing "Blame" through the Solution Explorer on a file opens TortoiseMerge rather than TortoiseBlame. Build 22 (beta) New: Visua...WPF Ink Canvas Toolbar: WPF Ink Canvas Toolbar 1.0: First release - included custom colour selectionMost Popular ProjectsRawrWBFS ManagerMicrosoft SQL Server Product Samples: DatabaseASP.NET Ajax LibrarySilverlight ToolkitAJAX Control ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesFacebook Developer ToolkitMost Active ProjectsGraffiti CMSnopCommerce. Open Source online shop e-commerce solution.RawrShweet: SharePoint 2010 Team Messaging built with Pexpatterns & practices – Enterprise LibraryAcadsysAutoPocoIonics Isapi Rewrite FilterNcqrs Framework - The CQRS framework for .NETFarseer Physics Engine

  Read the article

• SQL Server Master class winner

  - by Testas

   The winner of the SQL Server MasterClass competition courtesy of the UK SQL Server User Group and SQL Server Magazine!    Steve Hindmarsh     There is still time to register for the seminar yourself at:  www.regonline.co.uk/kimtrippsql     More information about the seminar     Where: Radisson Edwardian Heathrow Hotel, London  When: Thursday 17th June 2010  This one-day MasterClass will focus on many of the top issues companies face when implementing and maintaining a SQL Server-based solution. In the case where a company has no dedicated DBA, IT managers sometimes struggle to keep the data tier performing well and the data available. This can be especially troublesome when the development team is unfamiliar with the affect application design choices have on database performance. The Microsoft SQL Server MasterClass 2010 is presented by Paul S. Randal and Kimberly L. Tripp, two of the most experienced and respected people in the SQL Server world. Together they have over 30 years combined experience working with SQL Server in the field, and on the SQL Server product team itself. This is a unique opportunity to hear them present at a UK event which will: Debunk many of the ingrained misconceptions around SQL Server's behaviour    Show you disaster recovery techniques critical to preserving your company's life-blood - the data    Explain how a common application design pattern can wreak havoc in the database Walk through the top-10 points to follow around operations and maintenance for a well-performing and available data tier! Please Note: Agenda may be subject to change  Sessions Abstracts  KEYNOTE: Bridging the Gap Between Development and Production    Applications are commonly developed with little regard for how design choices will affect performance in production. This is often because developers don't realize the implications of their design on how SQL Server will be able to handle a high workload (e.g. blocking, fragmentation) and/or because there's no full-time trained DBA that can recognize production problems and help educate developers. The keynote sets the stage for the rest of the day. Discussing some of the issues that can arise, explaining how some can be avoided and highlighting some of the features in SQL 2008 that can help developers and DBAs make better use of SQL Server, and troubleshoot when things go wrong.   SESSION ONE: SQL Server Mythbusters  It's amazing how many myths and misconceptions have sprung up and persisted over the years about SQL Server - after many years helping people out on forums, newsgroups, and customer engagements, Paul and Kimberly have heard it all. Are there really non-logged operations? Can interrupting shrinks or rebuilds cause corruption? Can you override the server's MAXDOP setting? Will the server always do a table-scan to get a row count? Many myths lead to poor design choices and inappropriate maintenance practices so these are just a few of many, many myths that Paul and Kimberly will debunk in this fast-paced session on how SQL Server operates and should be managed and maintained.   SESSION TWO: Database Recovery Techniques Demo-Fest  Even if a company has a disaster recovery strategy in place, they need to practice to make sure that the plan will work when a disaster does strike. In this fast-paced demo session Paul and Kimberly will repeatedly do nasty things to databases and then show how they are recovered - demonstrating many techniques that can be used in production for disaster recovery. Not for the faint-hearted!   SESSION THREE: GUIDs: Use, Abuse, and How To Move Forward   Since the addition of the GUID (Microsoft’s implementation of the UUID), my life as a consultant and "tuner" has been busy. I’ve seen databases designed with GUID keys run fairly well with small workloads but completely fall over and fail because they just cannot scale. And, I know why GUIDs are chosen - it simplifies the handling of parent/child rows in your batches so you can reduce round-trips or avoid dealing with identity values. And, yes, sometimes it's even for distributed databases and/or security that GUIDs are chosen. I'm not entirely against ever using a GUID but overusing and abusing GUIDs just has to be stopped! Please, please, please let me give you better solutions and explanations on how to deal with your parent/child rows, round-trips and clustering keys!   SESSION 4: Essential Database Maintenance  In this session, Paul and Kimberly will run you through their top-ten database maintenance recommendations, with a lot of tips and tricks along the way. These are distilled from almost 30 years combined experience working with SQL Server customers and are geared towards making your databases more performant, more available, and more easily managed (to save you time!). Everything in this session will be practical and applicable to a wide variety of databases. Topics covered include: backups, shrinks, fragmentation, statistics, and much more! Focus will be on 2005 but we'll explain some of the key differences for 2000 and 2008 as well. Speaker Biographies     Kimberley L. Tripp Paul and Kimberly are a husband-and-wife team who own and run SQLskills.com, a world-renowned SQL Server consulting and training company. They are both SQL Server MVPs and Microsoft Regional Directors, with over 30 years of combined experience on SQL Server. Paul worked on the SQL Server team for nine years in development and management roles, writing many of the DBCC commands, and ultimately with responsibility for core Storage Engine for SQL Server 2008. Paul writes extensively on his blog (SQLskills.com/blogs/Paul) and for TechNet Magazine, for which he is also a Contributing Editor. Kimberly worked on the SQL Server team in the early 1990s as a tester and writer before leaving to found SQLskills and embrace her passion for teaching and consulting. Kimberly has been a staple at worldwide conferences since she first presented at TechEd in 1996, and she blogs at SQLskills.com/blogs/Kimberly. They have written Microsoft whitepapers and books for SQL Server 2000, 2005 and 2008, and are regular, top-rated presenters worldwide on database maintenance, high availability, disaster recovery, performance tuning, and SQL Server internals. Together they teach the SQL MCM certification and throughout Microsoft.In their spare time, they like to find frogfish in remote corners of the world.   Speaker Testimonials  "To call them good trainers is an epic understatement. They know how to deliver technical material in ways that illustrate it well. I had to stop Paul at one point and ask him how long it took to build a particular slide because the animations were so good at conveying a hard-to-describe process." "These are not beginner presenters, and they put an extreme amount of preparation and attention to detail into everything that they do. Completely, utterly professional." "When it comes to the instructors themselves, Kimberly and Paul simply have no equal. Not only are they both ultimate authorities, but they have endless enthusiasm about the material, and spot on delivery. If either ever got tired they never showed it, even after going all day and all week. We witnessed countless demos over the course of the week, some extremely involved, multi-step processes, and I can’t recall one that didn’t go the way it was supposed to." "You might think that with this extreme level of skill comes extreme levels of egotism and lack of patience. Nothing could be further from the truth. ... They simply know how to teach, and are approachable, humble, and patient." "The experience Paul and Kimberly have had with real live customers yields a lot more information and things to watch out for than you'd ever get from documentation alone." “Kimberly, I just wanted to send you an email to let you know how awesome you are! I have applied some of your indexing strategies to our website’s homegrown CMS and we are experiencing a significant performance increase. WOW....amazing tips delivered in an exciting way!  Thanks again” 

  Read the article

• Developer’s Life – Attitude and Communication – They Can Cause Problems – Notes from the Field #027

  - by Pinal Dave

  [Note from Pinal]: This is a 27th episode of Notes from the Field series. The biggest challenge for anyone is to understand human nature. We human have so many things on our mind at any moment of time. There are cases when what we say is not what we mean and there are cases where what we mean we do not say. We do say and things as per our mood and our agenda in mind. Sometimes there are incidents when our attitude creates confusion in the communication and we end up creating a situation which is absolutely not warranted. In this episode of the Notes from the Field series database expert Mike Walsh explains a very crucial issue we face in our career, which is not technical but more to relate to human nature. Read on this may be the best blog post you might read in recent times. In this week’s note from the field, I’m taking a slight departure from technical knowledge and concepts explained. We’ll be back to it next week, I’m sure. Pinal wanted us to explain some of the issues we bump into and how we see some of our customers arrive at problem situations and how we have helped get them back on the right track. Often it is a technical problem we are officially solving – but in a lot of cases as a consultant, we are really helping fix some communication difficulties. This is a technical blog post and not an “advice column” in a newspaper – but the longer I am a consultant, the more years I add to my experience in technology the more I learn that the vast majority of the problems we encounter have “soft skills” included in the chain of causes for the issue we are helping overcome. This is not going to be exhaustive but I hope that sharing four pieces of advice inspired by real issues starts a process of searching for places where we can be the cause of these challenges and look at fixing them in ourselves. Or perhaps we can begin looking at resolving them in teams that we manage. I’ll share three statements that I’ve either heard, read or said and talk about some of the communication or attitude challenges highlighted by the statement. 1 – “But that’s the SAN Administrator’s responsibility…” I heard that early on in my consulting career when talking with a customer who had serious corruption and no good recent backups – potentially no good backups at all. The statement doesn’t have to be this one exactly, but the attitude here is an attitude of “my job stops here, and I don’t care about the intent or principle of why I’m here.” It’s also a situation of having the attitude that as long as there is someone else to blame, I’m fine…  You see in this case, the DBA had a suspicion that the backups were not being handled right.  They were the DBA and they knew that they had responsibility to ensure SQL backups were good to go – it’s a basic requirement of a production DBA. In my “As A DBA Where Do I start?!” presentation, I argue that is job #1 of a DBA. But in this case, the thought was that there was someone else to blame. Rather than create extra work and take on responsibility it was decided to just let it be another team’s responsibility. This failed the company, the company’s customers and no one won. As technologists – we should strive to go the extra mile. If there is a lack of clarity around roles and responsibilities and we know it – we should push to get it resolved. Especially as the DBAs who should act as the advocates of the data contained in the databases we are responsible for. 2 – “We’ve always done it this way, it’s never caused a problem before!” Complacency. I have to say that many failures I’ve been paid good money to help recover from would have not happened had it been for an attitude of complacency. If any thoughts like this have entered your mind about your situation you may be suffering from it. If, while reading this, you get this sinking feeling in your stomach about that one thing you know should be fixed but haven’t done it.. Why don’t you stop and go fix it then come back.. “We should have better backups, but we’re on a SAN so we should be fine really.” “Technically speaking that could happen, but what are the chances?” “We’ll just clean that up as a fast follow” ..and so on. In the age of tightening IT budgets, increased expectations of up time, availability and performance there is no room for complacency. Our customers and business units expect – no demand – the best. Complacency says “we will give you second best or hopefully good enough and we accept the risk and know this may hurt us later. Sometimes an organization will opt for “good enough” and I agree with the concept that at times the perfect can be the enemy of the good. But when we make those decisions in a vacuum and are not reporting them up and discussing them as an organization that is different. That is us unilaterally choosing to do something less than the best and purposefully playing a game of chance. 3 – “This device must accept interference from other devices but not create any” I’ve paraphrased this one – but it’s something the Federal Communications Commission – a federal agency in the United States that regulates electronic communication – requires of all manufacturers of any device that could cause or receive interference electronically. I blogged in depth about this here (http://www.straightpathsql.com/archives/2011/07/relationship-advice-from-the-fcc/) so I won’t go into much detail other than to say this… If we all operated more on the premise that we should do our best to not be the cause of conflict, and to be less easily offended and less upset when we perceive offense life would be easier in many areas! This doesn’t always cause the issues we are called in to help out. Not directly. But where we see it is in unhealthy relationships between the various technology teams at a client. We’ll see teams hoarding knowledge, not sharing well with others and almost working against other teams instead of working with them. If you trace these problems back far enough it often stems from someone or some group of people violating this principle from the FCC. To Sum It Up Technology problems are easy to solve. At Linchpin People we help many customers get past the toughest technological challenge – and at the end of the day it is really just a repeatable process of pattern based troubleshooting, logical thinking and starting at the beginning and carefully stepping through to the end. It’s easy at the end of the day. The tough part of what we do as consultants is the people skills. Being able to help get teams working together, being able to help teams take responsibility, to improve team to team communication? That is the difficult part, and we get to use the soft skills on every engagement. Work on professional development (http://professionaldevelopment.sqlpass.org/) and see continuing improvement here, not just with technology. I can teach just about anyone how to be an excellent DBA and performance tuner, but some of these soft skills are much more difficult to teach. If you want to get started with performance analytics and triage of virtualized SQL Servers with the help of experts, read more over at Fix Your SQL Server. Reference: Pinal Dave (http://blog.sqlauthority.com)Filed under: Notes from the Field, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

  Read the article

• Oracle Flashback Technologies - Overview

  - by Sridhar_R-Oracle

  Oracle Flashback Technologies - IntroductionIn his May 29th 2014 blog, my colleague Joe Meeks introduced Oracle Maximum Availability Architecture (MAA) and discussed both planned and unplanned outages. Let’s take a closer look at unplanned outages. These can be caused by physical failures (e.g., server, storage, network, file deletion, physical corruption, site failures) or by logical failures – cases where all components and files are physically available, but data is incorrect or corrupt. These logical failures are usually caused by human errors or application logic errors. This blog series focuses on these logical errors – what causes them and how to address and recover from them using Oracle Database Flashback. In this introductory blog post, I’ll provide an overview of the Oracle Database Flashback technologies and will discuss the features in detail in future blog posts. Let’s get started. We are all human beings (unless a machine is reading this), and making mistakes is a part of what we do…often what we do best!  We “fat finger”, we spill drinks on keyboards, unplug the wrong cables, etc.  In addition, many of us, in our lives as DBAs or developers, must have observed, caused, or corrected one or more of the following unpleasant events: Accidentally updated a table with wrong values !! Performed a batch update that went wrong - due to logical errors in the code !! Dropped a table !! How do DBAs typically recover from these types of errors? First, data needs to be restored and recovered to the point-in-time when the error occurred (incomplete or point-in-time recovery).  Moreover, depending on the type of fault, it’s possible that some services – or even the entire database – would have to be taken down during the recovery process.Apart from error conditions, there are other questions that need to be addressed as part of the investigation. For example, what did the data look like in the morning, prior to the error? What were the various changes to the row(s) between two timestamps? Who performed the transaction and how can it be reversed?  Oracle Database includes built-in Flashback technologies, with features that address these challenges and questions, and enable you to perform faster, easier, and convenient recovery from logical corruptions. HistoryFlashback Query, the first Flashback Technology, was introduced in Oracle 9i. It provides a simple, powerful and completely non-disruptive mechanism for data verification and recovery from logical errors, and enables users to view the state of data at a previous point in time.Flashback Technologies were further enhanced in Oracle 10g, to provide fast, easy recovery at the database, table, row, and even at a transaction level.Oracle Database 11g introduced an innovative method to manage and query long-term historical data with Flashback Data Archive. The 11g release also introduced Flashback Transaction, which provides an easy, one-step operation to back out a transaction. Oracle Database versions 11.2.0.2 and beyond further enhanced the performance of these features. Note that all the features listed here work without requiring any kind of restore operation.In addition, Flashback features are fully supported with the new multi-tenant capabilities introduced with Oracle Database 12c, Flashback Features Oracle Flashback Database enables point-in-time-recovery of the entire database without requiring a traditional restore and recovery operation. It rewinds the entire database to a specified point in time in the past by undoing all the changes that were made since that time.Oracle Flashback Table enables an entire table or a set of tables to be recovered to a point in time in the past.Oracle Flashback Drop enables accidentally dropped tables and all dependent objects to be restored.Oracle Flashback Query enables data to be viewed at a point-in-time in the past. This feature can be used to view and reconstruct data that was lost due to unintentional change(s) or deletion(s). This feature can also be used to build self-service error correction into applications, empowering end-users to undo and correct their errors.Oracle Flashback Version Query offers the ability to query the historical changes to data between two points in time or system change numbers (SCN) Oracle Flashback Transaction Query enables changes to be examined at the transaction level. This capability can be used to diagnose problems, perform analysis, audit transactions, and even revert the transaction by undoing SQLOracle Flashback Transaction is a procedure used to back-out a transaction and its dependent transactions.Flashback technologies eliminate the need for a traditional restore and recovery process to fix logical corruptions or make enquiries. Using these technologies, you can recover from the error in the same amount of time it took to generate the error. All the Flashback features can be accessed either via SQL command line (or) via Enterprise Manager.  Most of the Flashback technologies depend on the available UNDO to retrieve older data. The following table describes the various Flashback technologies: their purpose, dependencies and situations where each individual technology can be used.   Example Syntax Error investigation related:The purpose is to investigate what went wrong and what the values were at certain points in timeFlashback Queries  ( select .. as of SCN | Timestamp )   - Helps to see the value of a row/set of rows at a point in timeFlashback Version Queries  ( select .. versions between SCN | Timestamp and SCN | Timestamp)  - Helps determine how the value evolved between certain SCNs or between timestamps Flashback Transaction Queries (select .. XID=)   - Helps to understand how the transaction caused the changes.Error correction related:The purpose is to fix the error and correct the problems,Flashback Table  (flashback table .. to SCN | Timestamp)  - To rewind the table to a particular timestamp or SCN to reverse unwanted updates Flashback Drop (flashback table ..  to before drop )  - To undrop or undelete a table Flashback Database (flashback database to SCN  | Restore Point )  - This is the rewind button for Oracle databases. You can revert the entire database to a particular point in time. It is a fast way to perform a PITR (point-in-time recovery). Flashback Transaction (DBMS_FLASHBACK.TRANSACTION_BACKOUT(XID..))  - To reverse a transaction and its related transactions Advanced use cases Flashback technology is integrated into Oracle Recovery Manager (RMAN) and Oracle Data Guard. So, apart from the basic use cases mentioned above, the following use cases are addressed using Oracle Flashback. Block Media recovery by RMAN - to perform block level recovery Snapshot Standby - where the standby is temporarily converted to a read/write environment for testing, backup, or migration purposes Re-instate old primary in a Data Guard environment – this avoids the need to restore an old backup and perform a recovery to make it a new standby. Guaranteed Restore Points - to bring back the entire database to an older point-in-time in a guaranteed way. and so on..I hope this introductory overview helps you understand how Flashback features can be used to investigate and recover from logical errors.  As mentioned earlier, I will take a deeper-dive into to some of the critical Flashback features in my upcoming blogs and address common use cases.

  Read the article

• How to Tell a Hardware Problem From a Software Problem

  - by Chris Hoffman

  Your computer seems to be malfunctioning — it’s slow, programs are crashing or Windows may be blue-screening. Is your computer’s hardware failing, or does it have a software problem that you can fix on your own? This can actually be a bit tricky to figure out. Hardware problems and software problems can lead to the same symptoms — for example, frequent blue screens of death may be caused by either software or hardware problems. Computer is Slow We’ve all heard the stories — someone’s computer slows down over time because they install too much software that runs at startup or it becomes infected with malware. The person concludes that their computer is slowing down because it’s old, so they replace it. But they’re wrong. If a computer is slowing down, it has a software problem that can be fixed. Hardware problems shouldn’t cause your computer to slow down. There are some rare exceptions to this — perhaps your CPU is overheating and it’s downclocking itself, running slower to stay cooler — but most slowness is caused by software issues. Blue Screens Modern versions of Windows are much more stable than older versions of Windows. When used with reliable hardware with well-programmed drivers, a typical Windows computer shouldn’t blue-screen at all. If you are encountering frequent blue screens of death, there’s a good chance your computer’s hardware is failing. Blue screens could also be caused by badly programmed hardware drivers, however. If you just installed or upgraded hardware drivers and blue screens start, try uninstalling the drivers or using system restore — there may be something wrong with the drivers. If you haven’t done anything with your drivers recently and blue screens start, there’s a very good chance you have a hardware problem. Computer Won’t Boot If your computer won’t boot, you could have either a software problem or a hardware problem. Is Windows attempting to boot and failing part-way through the boot process, or does the computer no longer recognize its hard drive or not power on at all? Consult our guide to troubleshooting boot problems for more information. When Hardware Starts to Fail… Here are some common components that can fail and the problems their failures may cause: Hard Drive: If your hard drive starts failing, files on your hard drive may become corrupted. You may see long delays when you attempt to access files or save to the hard drive. Windows may stop booting entirely. CPU: A failing CPU may result in your computer not booting at all. If the CPU is overheating, your computer may blue-screen when it’s under load — for example, when you’re playing a demanding game or encoding video. RAM: Applications write data to your RAM and use it for short-term storage. If your RAM starts failing, an application may write data to part of the RAM, then later read it back and get an incorrect value. This can result in application crashes, blue screens, and file corruption. Graphics Card: Graphics card problems may result in graphical errors while rendering 3D content or even just while displaying your desktop. If the graphics card is overheating, it may crash your graphics driver or cause your computer to freeze while under load — for example, when playing demanding 3D games. Fans: If any of the fans fail in your computer, components may overheat and you may see the above CPU or graphics card problems. Your computer may also shut itself down abruptly so it doesn’t overheat any further and damage itself. Motherboard: Motherboard problems can be extremely tough to diagnose. You may see occasional blue screens or similar problems. Power Supply: A malfunctioning power supply is also tough to diagnose — it may deliver too much power to a component, damaging it and causing it to malfunction. If the power supply dies completely, your computer won’t power on and nothing will happen when you press the power button. Other common problems — for example, a computer slowing down — are likely to be software problems. It’s also possible that software problems can cause many of the above symptoms — malware that hooks deep into the Windows kernel can cause your computer to blue-screen, for example. The Only Way to Know For Sure We’ve tried to give you some idea of the difference between common software problems and hardware problems with the above examples. But it’s often tough to know for sure, and troubleshooting is usually a trial-and-error process. This is especially true if you have an intermittent problem, such as your computer blue-screening a few times a week. You can try scanning your computer for malware and running System Restore to restore your computer’s system software back to its previous working state, but these aren’t  guaranteed ways to fix software problems. The best way to determine whether the problem you have is a software or hardware one is to bite the bullet and restore your computer’s software back to its default state. That means reinstalling Windows or using the Refresh or reset feature on Windows 8. See whether the problem still persists after you restore its operating system to its default state. If you still see the same problem – for example, if your computer is blue-screening and continues to blue-screen after reinstalling Windows — you know you have a hardware problem and need to have your computer fixed or replaced. If the computer crashes or freezes while reinstalling Windows, you definitely have a hardware problem. Even this isn’t a completely perfect method — for example, you may reinstall Windows and install the same hardware drivers afterwards. If the hardware drivers are badly programmed, the blue-screens may continue. Blue screens of death aren’t as common on Windows these days — if you’re encountering them frequently, you likely have a hardware problem. Most blue screens you encounter will likely be caused by hardware issues. On the other hand, other common complaints like “my computer has slowed down” are easily fixable software problems. When in doubt, back up your files and reinstall Windows. Image Credit: Anders Sandberg on Flickr, comedy_nose on Flickr     

  Read the article

• Merge replication stopping without errors in SQL 2008 R2

  - by Rob Farley

  A non-SQL MVP friend of mine, who also happens to be a client, asked me for some help again last week. I was planning on writing this up even before Rob Volk (@sql_r) listed his T-SQL Tuesday topic for this month. Earlier in the year, I (well, LobsterPot Solutions, although I’d been the person mostly involved) had helped out with a merge replication problem. The Merge Agent on the subscriber was just stopping every time, shortly after it started. With no errors anywhere – not in the Windows Event Log, the SQL Agent logs, not anywhere. We’d managed to get the system working again, but didn’t have a good reason about what had happened, and last week, the problem occurred again. I asked him about writing up the experience in a blog post, largely because of the red herrings that we encountered. It was an interesting experience for me, also because I didn’t end up touching my computer the whole time – just tapping on my phone via Twitter and Live Msgr. You see, the thing with replication is that a useful troubleshooting option is to reinitialise the thing. We’d done that last time, and it had started to work again – eventually. I say eventually, because the link being used between the sites is relatively slow, and it took a long while for the initialisation to finish. Meanwhile, we’d been doing some investigation into what the problem could be, and were suitably pleased when the problem disappeared. So I got a message saying that a replication problem had occurred again. Reinitialising wasn’t going to be an option this time either. In this scenario, the subscriber having the problem happened to be in a different domain to the publisher. The other subscribers (within the domain) were fine, just this one in a different domain had the problem. Part of the problem seemed to be a log file that wasn’t being backed up properly. They’d been trying to back up to a backup device that had a corruption, and the log file was growing. Turned out, this wasn’t related to the problem, but of course, any time you’re troubleshooting and you see something untoward, you wonder. Having got past that problem, my next thought was that perhaps there was a problem with the account being used. But the other subscribers were using the same account, without any problems. The client pointed out that that it was almost exactly six months since the last failure (later shown to be a complete red herring). It sounded like something might’ve expired. Checking through certificates and trusts showed no sign of anything, and besides, there wasn’t a problem running a command-prompt window using the account in question, from the subscriber box. ...except that when he ran the sqlcmd –E –S servername command I recommended, it failed with a Named Pipes error. I’ve seen problems with firewalls rejecting connections via Named Pipes but letting TCP/IP through, so I got him to look into SQL Configuration Manager to see what kind of connection was being preferred... Everything seemed fine. And strangely, he could connect via Management Studio. Turned out, he had a typo in the servername of the sqlcmd command. That particular red herring must’ve been reflected in his cheeks as he told me. During the time, I also pinged a friend of mine to find out who I should ask, and Ted Kruger (@onpnt) ‘s name came up. Ted (and thanks again, Ted – really) reconfirmed some of my thoughts around the idea of an account expiring, and also suggesting bumping up the logging to level 4 (2 is Verbose, 4 is undocumented ridiculousness). I’d just told the client to push the logging up to level 2, but the log file wasn’t appearing. Checking permissions showed that the user did have permission on the folder, but still no file was appearing. Then it was noticed that the user had been switched earlier as part of the troubleshooting, and switching it back to the real user caused the log file to appear. Still no errors. A lot more information being pushed out, but still no errors. Ted suggested making sure the FQDNs were okay from both ends, in case the servers were unable to talk to each other. DNS problems can lead to hassles which can stop replication from working. No luck there either – it was all working fine. Another server started to report a problem as well. These two boxes were both SQL 2008 R2 (SP1), while the others, still working, were SQL 2005. Around this time, the client tried an idea that I’d shown him a few years ago – using a Profiler trace to see what was being called on the servers. It turned out that the last call being made on the publisher was sp_MSenumschemachange. A quick interwebs search on that showed a problem that exists in SQL Server 2008 R2, when stored procedures have more than 4000 characters. Running that stored procedure (with the same parameters) manually on SQL 2005 listed three stored procedures, the first of which did indeed have more than 4000 characters. Still no error though, and the problem as listed at http://support.microsoft.com/kb/2539378 describes an error that should occur in the Event log. However, this problem is the type of thing that is fixed by a reinitialisation (because it doesn’t need to send the procedure change across as a transaction). And a look in the change history of the long stored procs (you all keep them, right?), showed that the problem from six months earlier could well have been down to this too. Applying SP2 (with sufficient paranoia about backups and how to get back out again if necessary) fixed the problem. The stored proc changes went through immediately after the service pack was applied, and it’s been running happily since. The funny thing is that I didn’t solve the problem. He had put the Profiler trace on the server, and had done the search that found a forum post pointing at this particular problem. I’d asked Ted too, and although he’d given some useful information, nothing that he’d come up with had actually been the solution either. Sometimes, asking for help is the most useful thing you can do. Often though, you don’t end up getting the help from the person you asked – the sounding board is actually what you need. @rob_farley

  Read the article

• I see no LOBs!

  - by Paul White

  Is it possible to see LOB (large object) logical reads from STATISTICS IO output on a table with no LOB columns? I was asked this question today by someone who had spent a good fraction of their afternoon trying to work out why this was occurring – even going so far as to re-run DBCC CHECKDB to see if any corruption had taken place.  The table in question wasn’t particularly pretty – it had grown somewhat organically over time, with new columns being added every so often as the need arose.  Nevertheless, it remained a simple structure with no LOB columns – no TEXT or IMAGE, no XML, no MAX types – nothing aside from ordinary INT, MONEY, VARCHAR, and DATETIME types.  To add to the air of mystery, not every query that ran against the table would report LOB logical reads – just sometimes – but when it did, the query often took much longer to execute. Ok, enough of the pre-amble.  I can’t reproduce the exact structure here, but the following script creates a table that will serve to demonstrate the effect: IF OBJECT_ID(N'dbo.Test', N'U') IS NOT NULL DROP TABLE dbo.Test GO CREATE TABLE dbo.Test ( row_id NUMERIC IDENTITY NOT NULL,   col01 NVARCHAR(450) NOT NULL, col02 NVARCHAR(450) NOT NULL, col03 NVARCHAR(450) NOT NULL, col04 NVARCHAR(450) NOT NULL, col05 NVARCHAR(450) NOT NULL, col06 NVARCHAR(450) NOT NULL, col07 NVARCHAR(450) NOT NULL, col08 NVARCHAR(450) NOT NULL, col09 NVARCHAR(450) NOT NULL, col10 NVARCHAR(450) NOT NULL, CONSTRAINT [PK dbo.Test row_id] PRIMARY KEY CLUSTERED (row_id) ) ; The next script loads the ten variable-length character columns with one-character strings in the first row, two-character strings in the second row, and so on down to the 450th row: WITH Numbers AS ( -- Generates numbers 1 - 450 inclusive SELECT TOP (450) n = ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM master.sys.columns C1, master.sys.columns C2, master.sys.columns C3 ORDER BY n ASC ) INSERT dbo.Test WITH (TABLOCKX) SELECT REPLICATE(N'A', N.n), REPLICATE(N'B', N.n), REPLICATE(N'C', N.n), REPLICATE(N'D', N.n), REPLICATE(N'E', N.n), REPLICATE(N'F', N.n), REPLICATE(N'G', N.n), REPLICATE(N'H', N.n), REPLICATE(N'I', N.n), REPLICATE(N'J', N.n) FROM Numbers AS N ORDER BY N.n ASC ; Once those two scripts have run, the table contains 450 rows and 10 columns of data like this: Most of the time, when we query data from this table, we don’t see any LOB logical reads, for example: -- Find the maximum length of the data in -- column 5 for a range of rows SELECT result = MAX(DATALENGTH(T.col05)) FROM dbo.Test AS T WHERE row_id BETWEEN 50 AND 100 ; But with a different query… -- Read all the data in column 1 SELECT result = MAX(DATALENGTH(T.col01)) FROM dbo.Test AS T ; …suddenly we have 49 LOB logical reads, as well as the ‘normal’ logical reads we would expect. The Explanation If we had tried to create this table in SQL Server 2000, we would have received a warning message to say that future INSERT or UPDATE operations on the table might fail if the resulting row exceeded the in-row storage limit of 8060 bytes.  If we needed to store more data than would fit in an 8060 byte row (including internal overhead) we had to use a LOB column – TEXT, NTEXT, or IMAGE.  These special data types store the large data values in a separate structure, with just a small pointer left in the original row. Row Overflow SQL Server 2005 introduced a feature called row overflow, which allows one or more variable-length columns in a row to move to off-row storage if the data in a particular row would otherwise exceed 8060 bytes.  You no longer receive a warning when creating (or altering) a table that might need more than 8060 bytes of in-row storage; if SQL Server finds that it can no longer fit a variable-length column in a particular row, it will silently move one or more of these columns off the row into a separate allocation unit. Only variable-length columns can be moved in this way (for example the (N)VARCHAR, VARBINARY, and SQL_VARIANT types).  Fixed-length columns (like INTEGER and DATETIME for example) never move into ‘row overflow’ storage.  The decision to move a column off-row is done on a row-by-row basis – so data in a particular column might be stored in-row for some table records, and off-row for others. In general, if SQL Server finds that it needs to move a column into row-overflow storage, it moves the largest variable-length column record for that row.  Note that in the case of an UPDATE statement that results in the 8060 byte limit being exceeded, it might not be the column that grew that is moved! Sneaky LOBs Anyway, that’s all very interesting but I don’t want to get too carried away with the intricacies of row-overflow storage internals.  The point is that it is now possible to define a table with non-LOB columns that will silently exceed the old row-size limit and result in ordinary variable-length columns being moved to off-row storage.  Adding new columns to a table, expanding an existing column definition, or simply storing more data in a column than you used to – all these things can result in one or more variable-length columns being moved off the row. Note that row-overflow storage is logically quite different from old-style LOB and new-style MAX data type storage – individual variable-length columns are still limited to 8000 bytes each – you can just have more of them now.  Having said that, the physical mechanisms involved are very similar to full LOB storage – a column moved to row-overflow leaves a 24-byte pointer record in the row, and the ‘separate storage’ I have been talking about is structured very similarly to both old-style LOBs and new-style MAX types.  The disadvantages are also the same: when SQL Server needs a row-overflow column value it needs to follow the in-row pointer a navigate another chain of pages, just like retrieving a traditional LOB. And Finally… In the example script presented above, the rows with row_id values from 402 to 450 inclusive all exceed the total in-row storage limit of 8060 bytes.  A SELECT that references a column in one of those rows that has moved to off-row storage will incur one or more lob logical reads as the storage engine locates the data.  The results on your system might vary slightly depending on your settings, of course; but in my tests only column 1 in rows 402-450 moved off-row.  You might like to play around with the script – updating columns, changing data type lengths, and so on – to see the effect on lob logical reads and which columns get moved when.  You might even see row-overflow columns moving back in-row if they are updated to be smaller (hint: reduce the size of a column entry by at least 1000 bytes if you hope to see this). Be aware that SQL Server will not warn you when it moves ‘ordinary’ variable-length columns into overflow storage, and it can have dramatic effects on performance.  It makes more sense than ever to choose column data types sensibly.  If you make every column a VARCHAR(8000) or NVARCHAR(4000), and someone stores data that results in a row needing more than 8060 bytes, SQL Server might turn some of your column data into pseudo-LOBs – all without saying a word. Finally, some people make a distinction between ordinary LOBs (those that can hold up to 2GB of data) and the LOB-like structures created by row-overflow (where columns are still limited to 8000 bytes) by referring to row-overflow LOBs as SLOBs.  I find that quite appealing, but the ‘S’ stands for ‘small’, which makes expanding the whole acronym a little daft-sounding…small large objects anyone? © Paul White 2011 email: [email protected] twitter: @SQL_Kiwi

  Read the article

• Master-slave vs. peer-to-peer archictecture: benefits and problems

  - by Ashok_Ora

  Normal 0 false false false EN-US X-NONE X-NONE Almost two decades ago, I was a member of a database development team that introduced adaptive locking. Locking, the most popular concurrency control technique in database systems, is pessimistic. Locking ensures that two or more conflicting operations on the same data item don’t “trample” on each other’s toes, resulting in data corruption. In a nutshell, here’s the issue we were trying to address. In everyday life, traffic lights serve the same purpose. They ensure that traffic flows smoothly and when everyone follows the rules, there are no accidents at intersections. As I mentioned earlier, the problem with typical locking protocols is that they are pessimistic. Regardless of whether there is another conflicting operation in the system or not, you have to hold a lock! Acquiring and releasing locks can be quite expensive, depending on how many objects the transaction touches. Every transaction has to pay this penalty. To use the earlier traffic light analogy, if you have ever waited at a red light in the middle of nowhere with no one on the road, wondering why you need to wait when there’s clearly no danger of a collision, you know what I mean. The adaptive locking scheme that we invented was able to minimize the number of locks that a transaction held, by detecting whether there were one or more transactions that needed conflicting eyou could get by without holding any lock at all. In many “well-behaved” workloads, there are few conflicts, so this optimization is a huge win. If, on the other hand, there are many concurrent, conflicting requests, the algorithm gracefully degrades to the “normal” behavior with minimal cost. We were able to reduce the number of lock requests per TPC-B transaction from 178 requests down to 2! Wow! This is a dramatic improvement in concurrency as well as transaction latency. The lesson from this exercise was that if you can identify the common scenario and optimize for that case so that only the uncommon scenarios are more expensive, you can make dramatic improvements in performance without sacrificing correctness. So how does this relate to the architecture and design of some of the modern NoSQL systems? NoSQL systems can be broadly classified as master-slave sharded, or peer-to-peer sharded systems. NoSQL systems with a peer-to-peer architecture have an interesting way of handling changes. Whenever an item is changed, the client (or an intermediary) propagates the changes synchronously or asynchronously to multiple copies (for availability) of the data. Since the change can be propagated asynchronously, during some interval in time, it will be the case that some copies have received the update, and others haven’t. What happens if someone tries to read the item during this interval? The client in a peer-to-peer system will fetch the same item from multiple copies and compare them to each other. If they’re all the same, then every copy that was queried has the same (and up-to-date) value of the data item, so all’s good. If not, then the system provides a mechanism to reconcile the discrepancy and to update stale copies. So what’s the problem with this? There are two major issues: First, IT’S HORRIBLY PESSIMISTIC because, in the common case, it is unlikely that the same data item will be updated and read from different locations at around the same time! For every read operation, you have to read from multiple copies. That’s a pretty expensive, especially if the data are stored in multiple geographically separate locations and network latencies are high. Second, if the copies are not all the same, the application has to reconcile the differences and propagate the correct value to the out-dated copies. This means that the application program has to handle discrepancies in the different versions of the data item and resolve the issue (which can further add to cost and operation latency). Resolving discrepancies is only one part of the problem. What if the same data item was updated independently on two different nodes (copies)? In that case, due to the asynchronous nature of change propagation, you might land up with different versions of the data item in different copies. In this case, the application program also has to resolve conflicts and then propagate the correct value to the copies that are out-dated or have incorrect versions. This can get really complicated. My hunch is that there are many peer-to-peer-based applications that don’t handle this correctly, and worse, don’t even know it. Imagine have 100s of millions of records in your database – how can you tell whether a particular data item is incorrect or out of date? And what price are you willing to pay for ensuring that the data can be trusted? Multiple network messages per read request? Discrepancy and conflict resolution logic in the application, and potentially, additional messages? All this overhead, when all you were trying to do was to read a data item. Wouldn’t it be simpler to avoid this problem in the first place? Master-slave architectures like the Oracle NoSQL Database handles this very elegantly. A change to a data item is always sent to the master copy. Consequently, the master copy always has the most current and authoritative version of the data item. The master is also responsible for propagating the change to the other copies (for availability and read scalability). Client drivers are aware of master copies and replicas, and client drivers are also aware of the “currency” of a replica. In other words, each NoSQL Database client knows how stale a replica is. This vastly simplifies the job of the application developer. If the application needs the most current version of the data item, the client driver will automatically route the request to the master copy. If the application is willing to tolerate some staleness of data (e.g. a version that is no more than 1 second out of date), the client can easily determine which replica (or set of replicas) can satisfy the request, and route the request to the most efficient copy. This results in a dramatic simplification in application logic and also minimizes network requests (the driver will only send the request to exactl the right replica, not many). So, back to my original point. A well designed and well architected system minimizes or eliminates unnecessary overhead and avoids pessimistic algorithms wherever possible in order to deliver a highly efficient and high performance system. If you’ve every programmed an Oracle NoSQL Database application, you’ll know the difference! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

  Read the article

• ?Oracle????SELECT????UNDO

  - by Liu Maclean(???)

  ????????Oracle?????(dirty read),?Oracle??????Asktom????????Oracle???????, ???undo??????????(before image)??????Consistent, ???????????????Oracle????????????? ????????? ??,??,Oracle?????????????RDBMS,???????????? ?????????2?????: _offline_rollback_segments or _corrupted_rollback_segments ?2?????????Oracle???????????ORA-600[4XXX]???????????????,???2??????Undo??Corruption????????????,?????2????????????????? ??????????????_offline_rollback_segments ? _corrupted_rollback_segments ?2?????: ???????(FORCE OPEN DATABASE) ????????????(consistent read & delayed block cleanout) ??????rollback segment??? ?????:???????Oracle????????,??????????2?????,?????????????!! _offline_rollback_segments ? _corrupted_rollback_segments ???????????: ??2???????Undo Segments(???/???)????????online ?UNDO$???????????OFFLINE??? ???instance??????????????????? ??????Undo Segments????????active transaction????????????dead??SMON???(????????SMON??(?):Recover Dead transaction) _OFFLINE_ROLLBACK_SEGMENTS(offline undo segment list)????(hidden parameter)?????: ???startup???open database???????_OFFLINE_ROLLBACK_SEGMENTS????Undo segments(???/???),?????undo segments????????alert.log???TRACE?????,???????startup?? ?????????????,?ITL?????undo segments?: ???undo segments?transaction table?????????????????? ???????????commit,?????CR??? ????undo segments????(???corrupted??,???missed??)???????????alert.log,??????? ?DML?????????????????????????????????CPU,????????????????????? _CORRUPTED_ROLLBACK_SEGMENTS(corrupted undo segment list)??????????: ?????startup?open database???_CORRUPTED_ROLLBACK_SEGMENTS????undo segments(???/???)???????? ???????_CORRUPTED_ROLLBACK_SEGMENTS???undo segments????????????commit,???undo segments???drop??? ??????????? ??????????????????,?????????????????? ??bootstrap???????????,?????????ORA-00704: bootstrap process failure??,???????????(???Oracle????:??ORA-00600:[4000] ORA-00704: bootstrap process failure????) ??????_CORRUPTED_ROLLBACK_SEGMENTS????????????????????,??????????????? Oracle???????TXChecker??????????? ???????2?????,??????????????_CORRUPTED_ROLLBACK_SEGMENTS?????SELECT????UNDO???????: SQL> alter system set event= '10513 trace name context forever, level 2' scope=spfile; System altered. SQL> alter system set "_in_memory_undo"=false scope=spfile; System altered. 10513 level 2 event????SMON ??rollback ??? dead transaction _in_memory_undo ?? in memory undo ?? SQL> startup force; ORACLE instance started. Total System Global Area 3140026368 bytes Fixed Size 2232472 bytes Variable Size 1795166056 bytes Database Buffers 1325400064 bytes Redo Buffers 17227776 bytes Database mounted. Database opened. session A: SQL> conn maclean/maclean Connected. SQL> create table maclean tablespace users as select 1 t1 from dual connect by level exec dbms_stats.gather_table_stats('','MACLEAN'); PL/SQL procedure successfully completed. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 1 recursive calls 0 db block gets 3 consistent gets 0 physical reads 0 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processe ???????????,????current block, ????????,consistent gets??3? SQL> update maclean set t1=0; 501 rows updated. SQL> alter system checkpoint; System altered. ??session A?commit; ???? session: SQL> conn maclean/maclean Connected. SQL> SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 505 consistent gets 0 physical reads 108 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ?????? ?????????undo??CR?,???consistent gets??? 505 [oracle@vrh8 ~]$ ps -ef|grep LOCAL=YES |grep -v grep oracle 5841 5839 0 09:17 ? 00:00:00 oracleG10R25 (DESCRIPTION=(LOCAL=YES)(ADDRESS=(PROTOCOL=beq))) [oracle@vrh8 ~]$ kill -9 5841 ??session A???Server Process????,???dead transaction ????smon?? select ktuxeusn, to_char(sysdate, 'DD-MON-YYYY HH24:MI:SS') "Time", ktuxesiz, ktuxesta from x$ktuxe where ktuxecfl = 'DEAD'; KTUXEUSN Time KTUXESIZ KTUXESTA ---------- -------------------- ---------- ---------------- 2 06-AUG-2012 09:20:45 7 ACTIVE ???1?active rollback segment SQL> conn maclean/maclean Connected. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 501 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 411 consistent gets 0 physical reads 108 redo size 515 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ????? ????kill?? ???smon ??dead transaction , ???????????? ?????undo??????? ????active?rollback segment??? SQL> select segment_name from dba_rollback_segs where segment_id=2; SEGMENT_NAME ------------------------------ _SYSSMU2$ SQL> alter system set "_corrupted_rollback_segments"='_SYSSMU2$' scope=spfile; System altered. ? _corrupted_rollback_segments ?? ???2?rollback segment, ????????undo SQL> startup force; ORACLE instance started. Total System Global Area 3140026368 bytes Fixed Size 2232472 bytes Variable Size 1795166056 bytes Database Buffers 1325400064 bytes Redo Buffers 17227776 bytes Database mounted. Database opened. SQL> conn maclean/maclean Connected. SQL> set autotrace on; SQL> select sum(t1) from maclean; SUM(T1) ---------- 94 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 228 recursive calls 0 db block gets 29 consistent gets 5 physical reads 116 redo size 514 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 4 sorts (memory) 0 sorts (disk) 1 rows processed SQL> / SUM(T1) ---------- 94 Execution Plan ---------------------------------------------------------- Plan hash value: 1679547536 ------------------------------------------------------------------------------ | Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | ------------------------------------------------------------------------------ | 0 | SELECT STATEMENT | | 1 | 3 | 3 (0)| 00:00:01 | | 1 | SORT AGGREGATE | | 1 | 3 | | | | 2 | TABLE ACCESS FULL| MACLEAN | 501 | 1503 | 3 (0)| 00:00:01 | ------------------------------------------------------------------------------ Statistics ---------------------------------------------------------- 0 recursive calls 0 db block gets 3 consistent gets 0 physical reads 0 redo size 514 bytes sent via SQL*Net to client 492 bytes received via SQL*Net from client 2 SQL*Net roundtrips to/from client 0 sorts (memory) 0 sorts (disk) 1 rows processed ?????? consistent gets???3,?????????????????,??ITL???UNDO SEGMENTS?_corrupted_rollback_segments????,???????????COMMIT??,????UNDO? ???????,?????????????????????????(????????????????????),????????????????? ???? , ?????

  Read the article

• NetBeans not liking libraries in lib-src

  - by DJTripleThreat

  I'm working on a project with a group that is using Eclipse, but I'm using Netbeans. Up until today this wasn't an issue. When updating from the repo they have added some source code as a library under a directory called /lib-src. When I try to compile the code I get an error that it can't find certain packages... these are the packages under /lib-src. Using NetBeans I can add the library as a folder so now the references to those packages are happy. However, I'm getting this new error when compiling: UNEXPECTED TOP-LEVEL ERROR: java.lang.OutOfMemoryError: Java heap space at java.util.HashMap.addEntry(HashMap.java:753) at java.util.HashMap.put(HashMap.java:385) at com.android.dx.dex.file.ClassDataItem.addStaticField(ClassDataItem.java:134) at com.android.dx.dex.file.ClassDefItem.addStaticField(ClassDefItem.java:280) at com.android.dx.dex.cf.CfTranslator.processFields(CfTranslator.java:159) at com.android.dx.dex.cf.CfTranslator.translate0(CfTranslator.java:130) at com.android.dx.dex.cf.CfTranslator.translate(CfTranslator.java:85) at com.android.dx.command.dexer.Main.processClass(Main.java:297) at com.android.dx.command.dexer.Main.processFileBytes(Main.java:276) at com.android.dx.command.dexer.Main.access$100(Main.java:56) at com.android.dx.command.dexer.Main$1.processFileBytes(Main.java:228) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:134) at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:190) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:122) at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:190) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:122) at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:190) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:122) at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:190) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:122) at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:190) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:122) at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:190) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:122) at com.android.dx.cf.direct.ClassPathOpener.processDirectory(ClassPathOpener.java:190) at com.android.dx.cf.direct.ClassPathOpener.processOne(ClassPathOpener.java:122) at com.android.dx.cf.direct.ClassPathOpener.process(ClassPathOpener.java:108) at com.android.dx.command.dexer.Main.processOne(Main.java:245) at com.android.dx.command.dexer.Main.processAllFiles(Main.java:183) at com.android.dx.command.dexer.Main.run(Main.java:139) at com.android.dx.command.dexer.Main.main(Main.java:120) at com.android.dx.command.Main.main(Main.java:87) /home/aaron/NetBeansProjects/xbmc-remote/nbproject/build-impl.xml:411: exec returned: 3 BUILD FAILED (total time: 1 minute 25 seconds) I can include the build-impl.xml file if you need it, but I don't think that is main issue. Any ideas?

  Read the article

• Mocking using boost::shared_ptr and AMOP

  - by Edison Gustavo Muenz

  Hi, I'm trying to write mocks using amop. I'm using Visual Studio 2008. I have this interface class: struct Interface { virtual void Activate() = 0; }; and this other class which receives pointers to this Interface, like this: struct UserOfInterface { void execute(Interface* iface) { iface->Activate(); } }; So I try to write some testing code like this: amop::TMockObject<Interface> mock; mock.Method(&Interface::Activate).Count(1); UserOfInterface user; user.execute((Interface*)mock); mock.Verifiy(); It works! So far so good, but what I really want is a boost::shared_ptr in the execute() method, so I write this: struct UserOfInterface { void execute(boost::shared_ptr<Interface> iface) { iface->Activate(); } }; How should the test code be now? I tried some things, like: amop::TMockObject<Interface> mock; mock.Method(&Interface::Activate).Count(1); UserOfInterface user; boost::shared_ptr<Interface> mockAsPtr((Interface*)mock); user.execute(mockAsPtr); mock.Verifiy(); It compiles, but obviously crashes, since at the end of the scope the variable 'mock' gets double destroyed (because of the stack variable 'mock' and the shared_ptr). I also tried to create the 'mock' variable on the heap: amop::TMockObject<Interface>* mock(new amop::TMockObject<Interface>); mock->Method(&Interface::Activate).Count(1); UserOfInterface user; boost::shared_ptr<Interface> mockAsPtr((Interface*)*mock); user.execute(mockAsPtr); mock->Verifiy(); But it doesn't work, somehow it enters an infinite loop, before I had a problem with boost not finding the destructor for the mocked object when the shared_ptr tried to delete the object. Has anyone used amop with boost::shared_ptr successfully?

  Read the article

• Stack Overflow problem in a recursive program in C

  - by Adi

  Hi all, I am getting a stack overflow in one of the recursive functions i am running.. Here is the code.. void* buddyMalloc(int req_size) { // Do something here return buddy_findout(original_index,req_size); // This is the recursive call } void *buddy_findout(int current_index,int req_size) { char *selected = NULL; if(front!=NULL) { if(current_index==original_index) { // Do something here return selected; } else { // Do Something here return buddy_findout(current_index+1,req_size); } } else { return buddy_findout(current_index-1,req_size); } } Consider the initial value of index to be 4. and it first do index-1 till it reaches 0 index. and then it comes back to index 4 by incrementing..This is wht i want to implement. But it gives a stack overflow with memory map in the command prompt : Here is the output from my shell : * glibc detected * ./473_mem: free(): invalid pointer: 0x00c274c0 * ======= Backtrace: ========= /lib/tls/i686/cmov/libc.so.6[0xb50ff1] /lib/tls/i686/cmov/libc.so.6[0xb526f2] /lib/tls/i686/cmov/libc.so.6(cfree+0x6d)[0xb557cd] ./473_mem[0x8048b44] ./473_mem[0x8048b74] ./473_mem[0x8048b74] ./473_mem[0x8048944] ./473_mem[0x8048c87] ./473_mem[0x8048d31] ./473_mem[0x8048f79] /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe6)[0xafcb56] ./473_mem[0x8048671] ======= Memory map: ======== 0017c000-00198000 r-xp 00000000 08:01 5224 /lib/libgcc_s.so.1 00198000-00199000 r--p 0001b000 08:01 5224 /lib/libgcc_s.so.1 00199000-0019a000 rw-p 0001c000 08:01 5224 /lib/libgcc_s.so.1 00260000-00284000 r-xp 00000000 08:01 1927 /lib/tls/i686/cmov/libm-2.10.1.so 00284000-00285000 r--p 00023000 08:01 1927 /lib/tls/i686/cmov/libm-2.10.1.so 00285000-00286000 rw-p 00024000 08:01 1927 /lib/tls/i686/cmov/libm-2.10.1.so 006cd000-006e8000 r-xp 00000000 08:01 6662 /lib/ld-2.10.1.so 006e8000-006e9000 r--p 0001a000 08:01 6662 /lib/ld-2.10.1.so 006e9000-006ea000 rw-p 0001b000 08:01 6662 /lib/ld-2.10.1.so 00aa9000-00aaa000 r-xp 00000000 00:00 0 [vdso] 00ae6000-00c24000 r-xp 00000000 08:01 1900 /lib/tls/i686/cmov/libc-2.10.1.so 00c24000-00c25000 ---p 0013e000 08:01 1900 /lib/tls/i686/cmov/libc-2.10.1.so 00c25000-00c27000 r--p 0013e000 08:01 1900 /lib/tls/i686/cmov/libc-2.10.1.so 00c27000-00c28000 rw-p 00140000 08:01 1900 /lib/tls/i686/cmov/libc-2.10.1.so 00c28000-00c2b000 rw-p 00000000 00:00 0 08048000-0804a000 r-xp 00000000 00:14 2176 /media/windows-share/OS/Project2/473_mem 0804a000-0804b000 r--p 00001000 00:14 2176 /media/windows-share/OS/Project2/473_mem 0804b000-0804c000 rw-p 00002000 00:14 2176 /media/windows-share/OS/Project2/473_mem 08483000-084a4000 rw-p 00000000 00:00 0 [heap] b7600000-b7621000 rw-p 00000000 00:00 0 b7621000-b7700000 ---p 00000000 00:00 0 b7716000-b7819000 rw-p 00000000 00:00 0 b7827000-b782a000 rw-p 00000000 00:00 0 bfb96000-bfbab000 rw-p 00000000 00:00 0 [stack] Aborted Thanks in advance adi

  Read the article

• 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?

  Read the article

< Previous Page | 53 54 55 56 57 58 59 60 61 62  | Next Page >