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• Getting started with Oracle Database In-Memory Part III - Querying The IM Column Store

  - by Maria Colgan

  In my previous blog posts, I described how to install, enable, and populate the In-Memory column store (IM column store). This weeks post focuses on how data is accessed within the IM column store. Let’s take a simple query “What is the most expensive air-mail order we have received to date?” SELECT Max(lo_ordtotalprice) most_expensive_order FROM lineorderWHERE  lo_shipmode = 5; The LINEORDER table has been populated into the IM column store and since we have no alternative access paths (indexes or views) the execution plan for this query is a full table scan of the LINEORDER table. You will notice that the execution plan has a new set of keywords “IN MEMORY" in the access method description in the Operation column. These keywords indicate that the LINEORDER table has been marked for INMEMORY and we may use the IM column store in this query. What do I mean by “may use”? There are a small number of cases were we won’t use the IM column store even though the object has been marked INMEMORY. This is similar to how the keyword STORAGE is used on Exadata environments. You can confirm that the IM column store was actually used by examining the session level statistics, but more on that later. For now let's focus on how the data is accessed in the IM column store and why it’s faster to access the data in the new column format, for analytical queries, rather than the buffer cache. There are four main reasons why accessing the data in the IM column store is more efficient. 1. Access only the column data needed The IM column store only has to scan two columns – lo_shipmode and lo_ordtotalprice – to execute this query while the traditional row store or buffer cache has to scan all of the columns in each row of the LINEORDER table until it reaches both the lo_shipmode and the lo_ordtotalprice column. 2. Scan and filter data in it's compressed format When data is populated into the IM column it is automatically compressed using a new set of compression algorithms that allow WHERE clause predicates to be applied against the compressed formats. This means the volume of data scanned in the IM column store for our query will be far less than the same query in the buffer cache where it will scan the data in its uncompressed form, which could be 20X larger. 3. Prune out any unnecessary data within each column The fastest read you can execute is the read you don’t do. In the IM column store a further reduction in the amount of data accessed is possible due to the In-Memory Storage Indexes(IM storage indexes) that are automatically created and maintained on each of the columns in the IM column store. IM storage indexes allow data pruning to occur based on the filter predicates supplied in a SQL statement. An IM storage index keeps track of minimum and maximum values for each column in each of the In-Memory Compression Unit (IMCU). In our query the WHERE clause predicate is on the lo_shipmode column. The IM storage index on the lo_shipdate column is examined to determine if our specified column value 5 exist in any IMCU by comparing the value 5 to the minimum and maximum values maintained in the Storage Index. If the value 5 is outside the minimum and maximum range for an IMCU, the scan of that IMCU is avoided. For the IMCUs where the value 5 does fall within the min, max range, an additional level of data pruning is possible via the metadata dictionary created when dictionary-based compression is used on IMCU. The dictionary contains a list of the unique column values within the IMCU. Since we have an equality predicate we can easily determine if 5 is one of the distinct column values or not. The combination of the IM storage index and dictionary based pruning, enables us to only scan the necessary IMCUs. 4. Use SIMD to apply filter predicates For the IMCU that need to be scanned Oracle takes advantage of SIMD vector processing (Single Instruction processing Multiple Data values). Instead of evaluating each entry in the column one at a time, SIMD vector processing allows a set of column values to be evaluated together in a single CPU instruction. The column format used in the IM column store has been specifically designed to maximize the number of column entries that can be loaded into the vector registers on the CPU and evaluated in a single CPU instruction. SIMD vector processing enables the Oracle Database In-Memory to scan billion of rows per second per core versus the millions of rows per second per core scan rate that can be achieved in the buffer cache. I mentioned earlier in this post that in order to confirm the IM column store was used; we need to examine the session level statistics. You can monitor the session level statistics by querying the performance views v$mystat and v$statname. All of the statistics related to the In-Memory Column Store begin with IM. You can see the full list of these statistics by typing: display_name format a30 SELECT display_name FROM v$statname WHERE  display_name LIKE 'IM%'; If we check the session statistics after we execute our query the results would be as follow; SELECT Max(lo_ordtotalprice) most_expensive_order FROM lineorderWHERE lo_shipmode = 5; SELECT display_name FROM v$statname WHERE  display_name IN ('IM scan CUs columns accessed',                        'IM scan segments minmax eligible',                        'IM scan CUs pruned'); As you can see, only 2 IMCUs were accessed during the scan as the majority of the IMCUs (44) in the LINEORDER table were pruned out thanks to the storage index on the lo_shipmode column. In next weeks post I will describe how you can control which queries use the IM column store and which don't. +Maria Colgan

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• Parner Webcast - Innovations in Products Program

  - by Richard Lefebvre

  We are pleased to invite you to join the Innovations in Products –webcast. Innovations in Products will present Oracle Applications' Product's new functions and features including sales positioning. The key objectives of these webcasts are to inspire System Integrator's implementation personnel to conduct successful after sales in their Customer projects. Innovations in Products will be presented on the 1st Monday of each quarter after the billable day (4:00 to 5:00 PM CET). The webcast is intended for System Integrator's Implementation Certified Specialists but Innovations in Products is open for other interested Oracle Applications system Integrator's personnel as well. At first, two Oracle representatives will discuss Oracle's contribution to Partners. Then you will see product breakout session followed by Q&A with Oracle Experts. Each session will last for maximum 1 hour. A Q&A document covering all questions and answers will be made available after the webcast. What are the Benefits for partners? Find out how Innovations in Products helps you to improve your after sales Discover new functions and features so you can enrich your Customers's solution Learn more about Oracle Applications products, especially sales positioning Hear crucial questions raised by colleague alike, learn from their interest Engage and present your questions to subject experts Be inspired of the richness of Oracle Application portfolio – for your and your customer’s benefit Note: Should you already be familiar with a specific Product, then choose another one. Doing so you would expand your knowledge of the overall Applications portfolio. Some presentations contain product demonstration, although these presentations are not intended to be extremely detailed technical presentations. Note: At the latter part of this email you have also 17 links into the recent Applications Products presentations and 6 links into the Public Sector Value Proposition presentations that were presented in Innovations in Industries -program. Product breakout sessions: Topics Speaker To Register Fusion Applications Technology and Extensibility: A next-generation platform that adapts to client needs. Matthew Johnson, Sr. Director, SCM Product Development, EMEA CLICK HERE Fusion Applications - Transforming your Back-Office Accounting Function: Changing how people work in back office functions to drive value add Liam Nolan, Director, ERP Product Development, EMEA CLICK HERE Fusion HCM & Talent Overview & Extensibility: A more in-depth look into a personalized HCM solution Synco Jonkeren, Vice-President HCM Product Development & Management, EMEA CLICK HERE Fusion HCM Compensation Planning: Compensate To Compete Rosie Warner, Director, HCM Sales Development CLICK HERE Enterprise PLM for the Product Value Chain: Oracle Enterprise PLM offers Industry specific solutions that cover the Product Value Chain Ulf Köster, Sales Development Leader Enterprise PLM, Oracle Western Europe CLICK HERE Oracle's Asset Management and Maintenance Solution: What you need to know to successfully implement Oracle Asset Management solutions within Oracle Installed Base Philip Carey, Asset Management and Maintenance Solution Specialist CLICK HERE For more details please visit Innovations in Products and other breakout sessions on OPN page. Delivery Format Innovations in Products –program is a series of FREE prerecorded Applications product presentations followed by Q&A. It will be delivered over the Web. Participants have the opportunity to submit questions during the web cast via chat and subject matter experts will provide verbal answers live. Innovations in Products consists of several parallel prerecorded product breakout sessions, each lasting for max. 1 hour. At first, two Oracle representatives will discuss Oracle’s contribution to Partners. Then you’ll see the product breakout sessions followed by Q&A with Oracle Experts. A Q&A document covering all questions and answers will be made available after the webcast. You can also see Innovations in Products afterwards as its content will be available online for the next 6-12 months. The next Innovations in Products web casts will be presented as follows: July 2nd 2012 October 1st 2012 January 14th 2013 April 8th 2013. Note: Depending on local network bandwidth please allow some seconds time the presentations to download. You might want to refresh your screen by pressing F5. Duration Maximum 1 hour For further information please contact me Markku Rouhiainen. Recent Innovations in Products presentations Applications Products presented on April the 2nd, 2012 Speaker To Register Fusion CRM: Effective, Efficient and Easy James Penfold , Senior Director, Applications Product Development and Product Management CLICK HERE Fusion HCM: Talent management overview performance, goals, talent review Jaime Losantos Viñolas, Director, HCM Sales Development CLICK HERE Distributed Order Management - Fusion SCM Solution Vikram K Singla, Business Development Director, Supply Chain Management Applications, UK CLICK HERE Oracle Transportation Management Dominic Regan, Senior Director Oracle Transportation Management EMEA CLICK HERE Oracle Value Chain Planning: Demantra Sales & Operation Planning and Demantra Demand Management Lionel Albert, Senior Director Value Chain Planning, EMEA CLICK HERE Oracle CX (Customer Experience) - formerly CEM: Powering Great Customer Experiences Maria Ramirez , CRM Presales Consultant, EPC CLICK HERE EPM 11.1.2.2 Overview Nicholas Cox , EMEA Sales Development Director - Enterprise Performance Management CLICK HERE Oracle Hyperion Profitability and Cost Management, 11.1.2.1 Daniela Lazar , Senior EPM Sales Consultant, EPC CLICK HERE January the 16th 2012 Speaker To Register CRM / ATG: Best-in-Class CRM & Commerce Maria Ramirez , Associate CRM Presales Consultant, EPC CLICK HERE CRM / Automate Business Rules for Maximum Efficiency with OPA (Oracle Policy Automation) Marco Nilo, Associate CRM Presales Consultant, EPC CLICK HERE CRM / InQuira Toby Baker, Principal Sales Consultant, CRM Product Specialist Team CLICK HERE EPM / Business Intelligence Foundation Suite – Sales and Product Updates Liviu Nitescu, Senior BI Sales Consultant, EPC CLICK HERE EPM / Hyperion Planning 11.1.2.1 - Sales & Product Updates Andreea Voinea, EPM Sales Consultant, EPC CLICK HERE ERP / JDE EnterpriseOne Fulfillment Management Overview Mirela Andreea Nasta , ERP Presales Consultant, EPC CLICK HERE ERP / Spotlights on iExpenses Elena Nita ,ERP Presales Consultant, EPC CLICK HERE MDM / Master Data Management Martin Boyd , Senior Director Product Strategy CLICK HERE Product break through session Fusion Applications Human Capital Management Rosie Warner , Director, HCM Sales Development CLICK HERE Recent Innovations in Industries Value Proposition presentations January the 16th 2012 Speaker To Register Process Modernisation Iemke Idsingh Public Sector Solutions Director CLICK HERE Shared Services Ann Smith Business Development Director, Shared Services CLICK HERE Strengthening Financial Discipline Whilst Delivering Cashable Savings Philippa Headley UK Sales Development Director Public Sector - EPM Solutions CLICK HERE Social Welfare Industry Solutions Christian Wernberg-Tougaard Industry Director - Social Welfare CLICK HERE Police Industry Solutions Jeff Penrose Solution Sales Director CLICK HERE Tax and Revenue Management Industry Solutions Andre van der Post Global Director - Tax Solutions and Strategy CLICK HERE  

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• ODI 12c - Aggregating Data

  - by David Allan

  This posting will look at the aggregation component that was introduced in ODI 12c. For many ETL tool users this shouldn't be a big surprise, its a little different than ODI 11g but for good reason. You can use this component for composing data with relational like operations such as sum, average and so forth. Also, Oracle SQL supports special functions called Analytic SQL functions, you can use a specially configured aggregation component or the expression component for these now in ODI 12c. In database systems an aggregate transformation is a transformation where the values of multiple rows are grouped together as input on certain criteria to form a single value of more significant meaning - that's exactly the purpose of the aggregate component. In the image below you can see the aggregate component in action within a mapping, for how this and a few other examples are built look at the ODI 12c Aggregation Viewlet here - the viewlet illustrates a simple aggregation being built and then some Oracle analytic SQL such as AVG(EMP.SAL) OVER (PARTITION BY EMP.DEPTNO) built using both the aggregate component and the expression component. In 11g you used to just write the aggregate expression directly on the target, this made life easy for some cases, but it wan't a very obvious gesture plus had other drawbacks with ordering of transformations (agg before join/lookup. after set and so forth) and supporting analytic SQL for example - there are a lot of postings from creative folks working around this in 11g - anything from customizing KMs, to bypassing aggregation analysis in the ODI code generator. The aggregate component has a few interesting aspects. 1. Firstly and foremost it defines the attributes projected from it - ODI automatically will perform the grouping all you do is define the aggregation expressions for those columns aggregated. In 12c you can control this automatic grouping behavior so that you get the code you desire, so you can indicate that an attribute should not be included in the group by, that's what I did in the analytic SQL example using the aggregate component. 2. The component has a few other properties of interest; it has a HAVING clause and a manual group by clause. The HAVING clause includes a predicate used to filter rows resulting from the GROUP BY clause. Because it acts on the results of the GROUP BY clause, aggregation functions can be used in the HAVING clause predicate, in 11g the filter was overloaded and used for both having clause and filter clause, this is no longer the case. If a filter is after an aggregate, it is after the aggregate (not sometimes after, sometimes having).  3. The manual group by clause let's you use special database grouping grammar if you need to. For example Oracle has a wealth of highly specialized grouping capabilities for data warehousing such as the CUBE function. If you want to use specialized functions like that you can manually define the code here. The example below shows the use of a manual group from an example in the Oracle database data warehousing guide where the SUM aggregate function is used along with the CUBE function in the group by clause. The SQL I am trying to generate looks like the following from the data warehousing guide; SELECT channel_desc, calendar_month_desc, countries.country_iso_code,       TO_CHAR(SUM(amount_sold), '9,999,999,999') SALES$ FROM sales, customers, times, channels, countries WHERE sales.time_id=times.time_id AND sales.cust_id=customers.cust_id AND   sales.channel_id= channels.channel_id  AND customers.country_id = countries.country_id  AND channels.channel_desc IN   ('Direct Sales', 'Internet') AND times.calendar_month_desc IN   ('2000-09', '2000-10') AND countries.country_iso_code IN ('GB', 'US') GROUP BY CUBE(channel_desc, calendar_month_desc, countries.country_iso_code); I can capture the source datastores, the filters and joins using ODI's dataset (or as a traditional flow) which enables us to incrementally design the mapping and the aggregate component for the sum and group by as follows; In the above mapping you can see the joins and filters declared in ODI's dataset, allowing you to capture the relationships of the datastores required in an entity-relationship style just like ODI 11g. The mix of ODI's declarative design and the common flow design provides for a familiar design experience. The example below illustrates flow design (basic arbitrary ordering) - a table load where only the employees who have maximum commission are loaded into a target. The maximum commission is retrieved from the bonus datastore and there is a look using employees as the driving table and only those with maximum commission projected. Hopefully this has given you a taster for some of the new capabilities provided by the aggregate component in ODI 12c. In summary, the actions should be much more consistent in behavior and more easily discoverable for users, the use of the components in a flow graph also supports arbitrary designs and the tool (rather than the interface designer) takes care of the realization using ODI's knowledge modules. Interested to know if a deep dive into each component is interesting for folks. Any thoughts? 

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• Data Source Security Part 4

  - by Steve Felts

  So far, I have covered Client Identity and Oracle Proxy Session features, with WLS or database credentials.  This article will cover one more feature, Identify-based pooling.  Then, there is one more topic to cover - how these options play with transactions.Identity-based Connection Pooling An identity based pool creates a heterogeneous pool of connections.  This allows applications to use a JDBC connection with a specific DBMS credential by pooling physical connections with different DBMS credentials.  The DBMS credential is based on either the WebLogic user mapped to a database user or the database user directly, based on the “use database credentials” setting as described earlier. Using this feature enabled with “use database credentials” enabled seems to be what is proposed in the JDBC standard, basically a heterogeneous pool with users specified by getConnection(user, password). The allocation of connections is more complex if Enable Identity Based Connection Pooling attribute is enabled on the data source.  When an application requests a database connection, the WebLogic Server instance selects an existing physical connection or creates a new physical connection with requested DBMS identity. The following section provides information on how heterogeneous connections are created:1. At connection pool initialization, the physical JDBC connections based on the configured or default “initial capacity” are created with the configured default DBMS credential of the data source.2. An application tries to get a connection from a data source.3a. If “use database credentials” is not enabled, the user specified in getConnection is mapped to a DBMS credential, as described earlier.  If the credential map doesn’t have a matching user, the default DBMS credential is used from the datasource descriptor.3b. If “use database credentials” is enabled, the user and password specified in getConnection are used directly.4. The connection pool is searched for a connection with a matching DBMS credential.5. If a match is found, the connection is reserved and returned to the application.6. If no match is found, a connection is created or reused based on the maximum capacity of the pool: - If the maximum capacity has not been reached, a new connection is created with the DBMS credential, reserved, and returned to the application.- If the pool has reached maximum capacity, based on the least recently used (LRU) algorithm, a physical connection is selected from the pool and destroyed. A new connection is created with the DBMS credential, reserved, and returned to the application. It should be clear that finding a matching connection is more expensive than a homogeneous pool.  Destroying a connection and getting a new one is very expensive.  If you can use a normal homogeneous pool or one of the light-weight options (client identity or an Oracle proxy connection), those should be used instead of identity based pooling. Regardless of how physical connections are created, each physical connection in the pool has its own DBMS credential information maintained by the pool. Once a physical connection is reserved by the pool, it does not change its DBMS credential even if the current thread changes its WebLogic user credential and continues to use the same connection. To configure this feature, select Enable Identity Based Connection Pooling.  See http://docs.oracle.com/cd/E24329_01/apirefs.1211/e24401/taskhelp/jdbc/jdbc_datasources/EnableIdentityBasedConnectionPooling.html  "Enable identity-based connection pooling for a JDBC data source" in Oracle WebLogic Server Administration Console Help. You must make the following changes to use Logging Last Resource (LLR) transaction optimization with Identity-based Pooling to get around the problem that multiple users will be accessing the associated transaction table.- You must configure a custom schema for LLR using a fully qualified LLR table name. All LLR connections will then use the named schema rather than the default schema when accessing the LLR transaction table.  - Use database specific administration tools to grant permission to access the named LLR table to all users that could access this table via a global transaction. By default, the LLR table is created during boot by the user configured for the connection in the data source. In most cases, the database will only allow access to this user and not allow access to mapped users. Connections within Transactions Now that we have covered the behavior of all of these various options, it’s time to discuss the exception to all of the rules.  When you get a connection within a transaction, it is associated with the transaction context on a particular WLS instance. When getting a connection with a data source configured with non-XA LLR or 1PC (using the JTS driver) with global transactions, the first connection obtained within the transaction is returned on subsequent connection requests regardless of the values of username/password specified and independent of the associated proxy user session, if any. The connection must be shared among all users of the connection when using LLR or 1PC. For XA data sources, the first connection obtained within the global transaction is returned on subsequent connection requests within the application server, regardless of the values of username/password specified and independent of the associated proxy user session, if any.  The connection must be shared among all users of the connection within a global transaction within the application server/JVM.

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• FreeBSD performance tuning. Sysctls, loader.conf, kernel

  - by SaveTheRbtz

  I wanted to share knowledge of tuning FreeBSD via sysctl.conf/loader.conf/KENCONF. It was initially based on Igor Sysoev's (author of nginx) presentation about FreeBSD tuning up to 100,000-200,000 active connections. Tunings are for FreeBSD-CURRENT. Since 7.2 amd64 some of them are tuned well by default. Prior 7.0 some of them are boot only (set via /boot/loader.conf) or does not exist at all. sysctl.conf: # No zero mapping feature # May break wine # (There are also reports about broken samba3) #security.bsd.map_at_zero=0 # If you have really busy webserver with apache13 you may run out of processes #kern.maxproc=10000 # Same for servers with apache2 / Pound #kern.threads.max_threads_per_proc=4096 # Max. backlog size kern.ipc.somaxconn=4096 # Shared memory // 7.2+ can use shared memory > 2Gb kern.ipc.shmmax=2147483648 # Sockets kern.ipc.maxsockets=204800 # Can cause this on older kernels: # http://old.nabble.com/Significant-performance-regression-for-increased-maxsockbuf-on-8.0-RELEASE-tt26745981.html#a26745981 ) kern.ipc.maxsockbuf=10485760 # Mbuf 2k clusters (on amd64 7.2+ 25600 is default) # For such high value vm.kmem_size must be increased to 3G kern.ipc.nmbclusters=262144 # Jumbo pagesize(_SC_PAGESIZE) clusters # Used as general packet storage for jumbo frames # can be monitored via `netstat -m` #kern.ipc.nmbjumbop=262144 # Jumbo 9k/16k clusters # If you are using them #kern.ipc.nmbjumbo9=65536 #kern.ipc.nmbjumbo16=32768 # For lower latency you can decrease scheduler's maximum time slice # default: stathz/10 (~ 13) #kern.sched.slice=1 # Increase max command-line length showed in `ps` (e.g for Tomcat/Java) # Default is PAGE_SIZE / 16 or 256 on x86 # This avoids commands to be presented as [executable] in `ps` # For more info see: http://www.freebsd.org/cgi/query-pr.cgi?pr=120749 kern.ps_arg_cache_limit=4096 # Every socket is a file, so increase them kern.maxfiles=204800 kern.maxfilesperproc=200000 kern.maxvnodes=200000 # On some systems HPET is almost 2 times faster than default ACPI-fast # Useful on systems with lots of clock_gettime / gettimeofday calls # See http://old.nabble.com/ACPI-fast-default-timecounter,-but-HPET-83--faster-td23248172.html # After revision 222222 HPET became default: http://svnweb.freebsd.org/base?view=revision&revision=222222 kern.timecounter.hardware=HPET # Small receive space, only usable on http-server, on file server this # should be increased to 65535 or even more #net.inet.tcp.recvspace=8192 # This is useful on Fat-Long-Pipes #net.inet.tcp.recvbuf_max=10485760 #net.inet.tcp.recvbuf_inc=65535 # Small send space is useful for http servers that serve small files # Autotuned since 7.x net.inet.tcp.sendspace=16384 # This is useful on Fat-Long-Pipes #net.inet.tcp.sendbuf_max=10485760 #net.inet.tcp.sendbuf_inc=65535 # Turn off receive autotuning # You can play with it. #net.inet.tcp.recvbuf_auto=0 #net.inet.tcp.sendbuf_auto=0 # This should be enabled if you going to use big spaces (>64k) # Also timestamp field is useful when using syncookies net.inet.tcp.rfc1323=1 # Turn this off on high-speed, lossless connections (LAN 1Gbit+) # If you set it there is no need in TCP_NODELAY sockopt (see man tcp) net.inet.tcp.delayed_ack=0 # This feature is useful if you are serving data over modems, Gigabit Ethernet, # or even high speed WAN links (or any other link with a high bandwidth delay product), # especially if you are also using window scaling or have configured a large send window. # Automatically disables on small RTT ( http://www.freebsd.org/cgi/cvsweb.cgi/src/sys/netinet/tcp_subr.c?#rev1.237 ) # This sysctl was removed in 10-CURRENT: # See: http://www.mail-archive.com/[email protected]/msg06178.html #net.inet.tcp.inflight.enable=0 # TCP slowstart algorithm tunings # We assuming we have very fast clients #net.inet.tcp.slowstart_flightsize=100 #net.inet.tcp.local_slowstart_flightsize=100 # Disable randomizing of ports to avoid false RST # Before usage check SA here www.bsdcan.org/2006/papers/ImprovingTCPIP.pdf # (it's also says that port randomization auto-disables at some conn.rates, but I didn't checked it thou) #net.inet.ip.portrange.randomized=0 # Increase portrange # For outgoing connections only. Good for seed-boxes and ftp servers. net.inet.ip.portrange.first=1024 net.inet.ip.portrange.last=65535 # # stops route cache degregation during a high-bandwidth flood # http://www.freebsd.org/doc/en/books/handbook/securing-freebsd.html #net.inet.ip.rtexpire=2 net.inet.ip.rtminexpire=2 net.inet.ip.rtmaxcache=1024 # Security net.inet.ip.redirect=0 net.inet.ip.sourceroute=0 net.inet.ip.accept_sourceroute=0 net.inet.icmp.maskrepl=0 net.inet.icmp.log_redirect=0 net.inet.icmp.drop_redirect=1 net.inet.tcp.drop_synfin=1 # # There is also good example of sysctl.conf with comments: # http://www.thern.org/projects/sysctl.conf # # icmp may NOT rst, helpful for those pesky spoofed # icmp/udp floods that end up taking up your outgoing # bandwidth/ifqueue due to all that outgoing RST traffic. # #net.inet.tcp.icmp_may_rst=0 # Security net.inet.udp.blackhole=1 net.inet.tcp.blackhole=2 # IPv6 Security # For more info see http://www.fosslc.org/drupal/content/security-implications-ipv6 # Disable Node info replies # To see this vulnerability in action run `ping6 -a sglAac ::1` or `ping6 -w ::1` on unprotected node net.inet6.icmp6.nodeinfo=0 # Turn on IPv6 privacy extensions # For more info see proposal http://unix.derkeiler.com/Mailing-Lists/FreeBSD/net/2008-06/msg00103.html net.inet6.ip6.use_tempaddr=1 net.inet6.ip6.prefer_tempaddr=1 # Disable ICMP redirect net.inet6.icmp6.rediraccept=0 # Disable acceptation of RA and auto linklocal generation if you don't use them #net.inet6.ip6.accept_rtadv=0 #net.inet6.ip6.auto_linklocal=0 # Increases default TTL, sometimes useful # Default is 64 net.inet.ip.ttl=128 # Lessen max segment life to conserve resources # ACK waiting time in miliseconds # (default: 30000. RFC from 1979 recommends 120000) net.inet.tcp.msl=5000 # Max bumber of timewait sockets net.inet.tcp.maxtcptw=200000 # Don't use tw on local connections # As of 15 Apr 2009. Igor Sysoev says that nolocaltimewait has some buggy realization. # So disable it or now till get fixed #net.inet.tcp.nolocaltimewait=1 # FIN_WAIT_2 state fast recycle net.inet.tcp.fast_finwait2_recycle=1 # Time before tcp keepalive probe is sent # default is 2 hours (7200000) #net.inet.tcp.keepidle=60000 # Should be increased until net.inet.ip.intr_queue_drops is zero net.inet.ip.intr_queue_maxlen=4096 # Interrupt handling via multiple CPU, but with context switch. # You can play with it. Default is 1; #net.isr.direct=0 # This is for routers only #net.inet.ip.forwarding=1 #net.inet.ip.fastforwarding=1 # This speed ups dummynet when channel isn't saturated net.inet.ip.dummynet.io_fast=1 # Increase dummynet(4) hash #net.inet.ip.dummynet.hash_size=2048 #net.inet.ip.dummynet.max_chain_len # Should be increased when you have A LOT of files on server # (Increase until vfs.ufs.dirhash_mem becomes lower) vfs.ufs.dirhash_maxmem=67108864 # Note from commit http://svn.freebsd.org/base/head@211031 : # For systems with RAID volumes and/or virtualization envirnments, where # read performance is very important, increasing this sysctl tunable to 32 # or even more will demonstratively yield additional performance benefits. vfs.read_max=32 # Explicit Congestion Notification (see http://en.wikipedia.org/wiki/Explicit_Congestion_Notification) net.inet.tcp.ecn.enable=1 # Flowtable - flow caching mechanism # Useful for routers #net.inet.flowtable.enable=1 #net.inet.flowtable.nmbflows=65535 # Extreme polling tuning #kern.polling.burst_max=1000 #kern.polling.each_burst=1000 #kern.polling.reg_frac=100 #kern.polling.user_frac=1 #kern.polling.idle_poll=0 # IPFW dynamic rules and timeouts tuning # Increase dyn_buckets till net.inet.ip.fw.curr_dyn_buckets is lower net.inet.ip.fw.dyn_buckets=65536 net.inet.ip.fw.dyn_max=65536 net.inet.ip.fw.dyn_ack_lifetime=120 net.inet.ip.fw.dyn_syn_lifetime=10 net.inet.ip.fw.dyn_fin_lifetime=2 net.inet.ip.fw.dyn_short_lifetime=10 # Make packets pass firewall only once when using dummynet # i.e. packets going thru pipe are passing out from firewall with accept #net.inet.ip.fw.one_pass=1 # shm_use_phys Wires all shared pages, making them unswappable # Use this to lessen Virtual Memory Manager's work when using Shared Mem. # Useful for databases #kern.ipc.shm_use_phys=1 # ZFS # Enable prefetch. Useful for sequential load type i.e fileserver. # FreeBSD sets vfs.zfs.prefetch_disable to 1 on any i386 systems and # on any amd64 systems with less than 4GB of avaiable memory # For additional info check this nabble thread http://old.nabble.com/Samba-read-speed-performance-tuning-td27964534.html #vfs.zfs.prefetch_disable=0 # On highload servers you may notice following message in dmesg: # "Approaching the limit on PV entries, consider increasing either the # vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable" vm.pmap.shpgperproc=2048 loader.conf: # Accept filters for data, http and DNS requests # Useful when your software uses select() instead of kevent/kqueue or when you under DDoS # DNS accf available on 8.0+ accf_data_load="YES" accf_http_load="YES" accf_dns_load="YES" # Async IO system calls aio_load="YES" # Linux specific devices in /dev # As for 8.1 it only /dev/full #lindev_load="YES" # Adds NCQ support in FreeBSD # WARNING! all ad[0-9]+ devices will be renamed to ada[0-9]+ # 8.0+ only #ahci_load="YES" #siis_load="YES" # FreeBSD 8.2+ # New Congestion Control for FreeBSD # http://caia.swin.edu.au/urp/newtcp/tools/cc_chd-readme-0.1.txt # http://www.ietf.org/proceedings/78/slides/iccrg-5.pdf # Initial merge commit message http://www.mail-archive.com/[email protected]/msg31410.html #cc_chd_load="YES" # Increase kernel memory size to 3G. # # Use ONLY if you have KVA_PAGES in kernel configuration, and you have more than 3G RAM # Otherwise panic will happen on next reboot! # # It's required for high buffer sizes: kern.ipc.nmbjumbop, kern.ipc.nmbclusters, etc # Useful on highload stateful firewalls, proxies or ZFS fileservers # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #vm.kmem_size="3G" # If your server has lots of swap (>4Gb) you should increase following value # according to http://lists.freebsd.org/pipermail/freebsd-hackers/2009-October/029616.html # Otherwise you'll be getting errors # "kernel: swap zone exhausted, increase kern.maxswzone" # kern.maxswzone="256M" # Older versions of FreeBSD can't tune maxfiles on the fly #kern.maxfiles="200000" # Useful for databases # Sets maximum data size to 1G # (FreeBSD 7.2+ amd64 users: Check that current value is lower!) #kern.maxdsiz="1G" # Maximum buffer size(vfs.maxbufspace) # You can check current one via vfs.bufspace # Should be lowered/upped depending on server's load-type # Usually decreased to preserve kmem # (default is 10% of mem) #kern.maxbcache="512M" # Sendfile buffers # For i386 only #kern.ipc.nsfbufs=10240 # FreeBSD 9+ # HPET "legacy route" support. It should allow HPET to work per-CPU # See http://www.mail-archive.com/[email protected]/msg03603.html #hint.atrtc.0.clock=0 #hint.attimer.0.clock=0 #hint.hpet.0.legacy_route=1 # syncache Hash table tuning net.inet.tcp.syncache.hashsize=1024 net.inet.tcp.syncache.bucketlimit=512 net.inet.tcp.syncache.cachelimit=65536 # Increased hostcache # Later host cache can be viewed via net.inet.tcp.hostcache.list hidden sysctl # Very useful for it's RTT RTTVAR # Must be power of two net.inet.tcp.hostcache.hashsize=65536 # hashsize * bucketlimit (which is 30 by default) # It allocates 255Mb (1966080*136) of RAM net.inet.tcp.hostcache.cachelimit=1966080 # TCP control-block Hash table tuning net.inet.tcp.tcbhashsize=4096 # Disable ipfw deny all # Should be uncommented when there is a chance that # kernel and ipfw binary may be out-of sync on next reboot #net.inet.ip.fw.default_to_accept=1 # # SIFTR (Statistical Information For TCP Research) is a kernel module that # logs a range of statistics on active TCP connections to a log file. # See prerelease notes http://groups.google.com/group/mailing.freebsd.current/browse_thread/thread/b4c18be6cdce76e4 # and man 4 sitfr #siftr_load="YES" # Enable superpages, for 7.2+ only # Also read http://lists.freebsd.org/pipermail/freebsd-hackers/2009-November/030094.html vm.pmap.pg_ps_enabled=1 # Usefull if you are using Intel-Gigabit NIC #hw.em.rxd=4096 #hw.em.txd=4096 #hw.em.rx_process_limit="-1" # Also if you have ALOT interrupts on NIC - play with following parameters # NOTE: You should set them for every NIC #dev.em.0.rx_int_delay: 250 #dev.em.0.tx_int_delay: 250 #dev.em.0.rx_abs_int_delay: 250 #dev.em.0.tx_abs_int_delay: 250 # There is also multithreaded version of em/igb drivers can be found here: # http://people.yandex-team.ru/~wawa/ # # for additional em monitoring and statistics use # sysctl dev.em.0.stats=1 ; dmesg # sysctl dev.em.0.debug=1 ; dmesg # Also after r209242 (-CURRENT) there is a separate sysctl for each stat variable; # Same tunings for igb #hw.igb.rxd=4096 #hw.igb.txd=4096 #hw.igb.rx_process_limit=100 # Some useful netisr tunables. See sysctl net.isr #net.isr.maxthreads=4 #net.isr.defaultqlimit=4096 #net.isr.maxqlimit: 10240 # Bind netisr threads to CPUs #net.isr.bindthreads=1 # # FreeBSD 9.x+ # Increase interface send queue length # See commit message http://svn.freebsd.org/viewvc/base?view=revision&revision=207554 #net.link.ifqmaxlen=1024 # Nicer boot logo =) loader_logo="beastie" And finally here is KERNCONF: # Just some of them, see also # cat /sys/{i386,amd64,}/conf/NOTES # This one useful only on i386 #options KVA_PAGES=512 # You can play with HZ in environments with high interrupt rate (default is 1000) # 100 is for my notebook to prolong it's battery life #options HZ=100 # Polling is goot on network loads with high packet rates and low-end NICs # NB! Do not enable it if you want more than one netisr thread #options DEVICE_POLLING # Eliminate datacopy on socket read-write # To take advantage with zero copy sockets you should have an MTU >= 4k # This req. is only for receiving data. # Read more in man zero_copy_sockets # Also this epic thread on kernel trap: # http://kerneltrap.org/node/6506 # Here Linus says that "anybody that does it that way (FreeBSD) is totally incompetent" #options ZERO_COPY_SOCKETS # Support TCP sign. Used for IPSec options TCP_SIGNATURE # There was stackoverflow found in KAME IPSec stack: # See http://secunia.com/advisories/43995/ # For quick workaround you can use `ipfw add deny proto ipcomp` options IPSEC # This ones can be loaded as modules. They described in loader.conf section #options ACCEPT_FILTER_DATA #options ACCEPT_FILTER_HTTP # Adding ipfw, also can be loaded as modules options IPFIREWALL # On 8.1+ you can disable verbose to see blocked packets on ipfw0 interface. # Also there is no point in compiling verbose into the kernel, because # now there is net.inet.ip.fw.verbose tunable. #options IPFIREWALL_VERBOSE #options IPFIREWALL_VERBOSE_LIMIT=10 options IPFIREWALL_FORWARD # Adding kernel NAT options IPFIREWALL_NAT options LIBALIAS # Traffic shaping options DUMMYNET # Divert, i.e. for userspace NAT options IPDIVERT # This is for OpenBSD's pf firewall device pf device pflog # pf's QoS - ALTQ options ALTQ options ALTQ_CBQ # Class Bases Queuing (CBQ) options ALTQ_RED # Random Early Detection (RED) options ALTQ_RIO # RED In/Out options ALTQ_HFSC # Hierarchical Packet Scheduler (HFSC) options ALTQ_PRIQ # Priority Queuing (PRIQ) options ALTQ_NOPCC # Required for SMP build # Pretty console # Manual can be found here http://forums.freebsd.org/showthread.php?t=6134 #options VESA #options SC_PIXEL_MODE # Disable reboot on Ctrl Alt Del #options SC_DISABLE_REBOOT # Change normal|kernel messages color options SC_NORM_ATTR=(FG_GREEN|BG_BLACK) options SC_KERNEL_CONS_ATTR=(FG_YELLOW|BG_BLACK) # More scroll space options SC_HISTORY_SIZE=8192 # Adding hardware crypto device device crypto device cryptodev # Useful network interfaces device vlan device tap #Virtual Ethernet driver device gre #IP over IP tunneling device if_bridge #Bridge interface device pfsync #synchronization interface for PF device carp #Common Address Redundancy Protocol device enc #IPsec interface device lagg #Link aggregation interface device stf #IPv4-IPv6 port # Also for my notebook, but may be used with Opteron device amdtemp # Same for Intel processors device coretemp # man 4 cpuctl device cpuctl # CPU control pseudo-device # Support for ECMP. More than one route for destination # Works even with default route so one can use it as LB for two ISP # For now code is unstable and panics (panic: rtfree 2) on route deletions. #options RADIX_MPATH # Multicast routing #options MROUTING #options PIM # Debug & DTrace options KDB # Kernel debugger related code options KDB_TRACE # Print a stack trace for a panic options KDTRACE_FRAME # amd64-only(?) options KDTRACE_HOOKS # all architectures - enable general DTrace hooks #options DDB #options DDB_CTF # all architectures - kernel ELF linker loads CTF data # Adaptive spining in lockmgr (8.x+) # See http://www.mail-archive.com/[email protected]/msg10782.html options ADAPTIVE_LOCKMGRS # UTF-8 in console (8.x+) #options TEKEN_UTF8 # FreeBSD 8.1+ # Deadlock resolver thread # For additional information see http://www.mail-archive.com/[email protected]/msg18124.html # (FYI: "resolution" is panic so use with caution) #options DEADLKRES # Increase maximum size of Raw I/O and sendfile(2) readahead #options MAXPHYS=(1024*1024) #options MAXBSIZE=(1024*1024) # For scheduler debug enable following option. # Debug will be available via `kern.sched.stats` sysctl # For more information see http://svnweb.freebsd.org/base/head/sys/conf/NOTES?view=markup #options SCHED_STATS If you are tuning network for maximum performance you may wish to play with ifconfig options like: # You can list all capabilities via `ifconfig -m` ifconfig [-]rxcsum [-]txcsum [-]tso [-]lro mtu In case you've enabled DDB in kernel config, you should edit your /etc/ddb.conf and add something like this to enable automatic reboot (and textdump as bonus): script kdb.enter.panic=textdump set; capture on; show pcpu; bt; ps; alltrace; capture off; call doadump; reset script kdb.enter.default=textdump set; capture on; bt; ps; capture off; call doadump; reset And do not forget to add ddb_enable="YES" to /etc/rc.conf Since FreeBSD 9 you can select to enable/disable flowcontrol on your NIC: # See http://en.wikipedia.org/wiki/Ethernet_flow_control and # http://www.mail-archive.com/[email protected]/msg07927.html for additional info ifconfig bge0 media auto mediaopt flowcontrol PS. Also most of FreeBSD's limits can be monitored by # vmstat -z and # limits PPS. variety of network counters can be monitored via # netstat -s In FreeBSD-9 netstat's -Q option appeared, try following command to display netisr stats # netstat -Q PPPS. also see # man 7 tuning PPPPS. I wanted to thank FreeBSD community, especially author of nginx - Igor Sysoev, nginx-ru@ and FreeBSD-performance@ mailing lists for providing useful information about FreeBSD tuning. FreeBSD WIP * Whats cooking for FreeBSD 7? * Whats cooking for FreeBSD 8? * Whats cooking for FreeBSD 9? So here is the question: What tunings are you using on yours FreeBSD servers? You can also post your /etc/sysctl.conf, /boot/loader.conf, kernel options, etc with description of its' meaning (do not copy-paste from sysctl -d). Don't forget to specify server type (web, smb, gateway, etc) Let's share experience!

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• MSCC: Global Windows Azure Bootcamp

  Mauritius participated and contributed to the Global Windows Azure Bootcamp 2014 (GWAB). Again! And this time stronger than ever, and together with 137 other locations in 56 countries world-wide. We had 62 named registrations, 7 guest additions and approximately 10 offline participants prior to the event day. Most interestingly the organisation of the GWAB through the MSCC helped to increased the number of craftsmen. The Mauritius Software Craftsmanship Community has currently 138 registered members - in less than one year! Only with those numbers we can proudly say that all the preparations and hard work towards this event already paid off. Personally, I'm really grateful that we had this kind of response and the feedback from some attendees confirmed that the MSCC is on the right track here on Cyber Island Mauritius. Inspired and motivated by the success of this event, rest assured that there will be more public events like the GWAB. This time it took some time to reflect on our meetup, following my first impression right on spot: "Wow, what an experience to organise and participate in this global event. Overall, I've been very pleased with the preparations and the event itself. Surely, there have been some nicks that we have to address and to improve for future activities like this. Quite frankly, we are not professional event organisers (not yet) but we learned a lot over the past couple of days. A big Thank You to our event sponsors, namely Microsoft Indian Ocean Islands & French Pacific, Ceridian Mauritius and Emtel. Without them this event wouldn't have happened - Thank You! And to the cool team members of Microsoft Student Partners (MSPs). You geeks did a great job! Thanks!" So, how many attendees did we actually have? 61! - Awesome - 61 cloud computing instances to help on the research of diabetes. During Saturday afternoon there was even an online publication on L'Express: Les développeurs mauriciens se joignent au combat contre le diabète Reactions of other attendees Don't take my word for granted... Here are some impressions and feedback from our participants: "Awesome event, really appreciated the presentations :-)" -- Kevin on event comments "very interesting and enriching." -- Diana on event comments "#gwab #gwabmru 2014 great success. Looking forward for gwab 2015" -- Wasiim on Twitter "Was there till the end. Awesome Event. I'll surely join upcoming meetup sessions :)" -- Luchmun on event comments "#gwabmru was not that cool. left early" -- Mohammad on Twitter The overall feedback is positive but we are absolutely aware that there quite a number of problems we had to face. We are already looking into that and ideas / action plans on how we will be able to improve it for future events. The sessions We started the day with welcoming speeches by Thierry Coret, Sr. Marketing Manager of Microsoft Indian Ocean Islands & French Pacific and Vidia Mooneegan, Managing Director and Sr. Vice President of Ceridian Mauritius. The clear emphasis was on the endless possibilities of cloud computing and how it can enable any kind of sectors here in the country. Then it was about time to set up the cloud computing services in order to contribute each attendees cloud computing resources to the global research of diabetes, a step by step guide presented by Arnaud Meslier, Technical Evangelist at Microsoft. Given a rendering package and a configuration file it was very interesting to follow the single steps in Windows Azure. Also, during the day we were not sure whether the set up had been correctly, as Mauritius didn't show up on the results board - which should have been the case after approximately 20 to 30 minutes. Anyways, let the minions work... Next, Arnaud gave a brief overview of the variety of services Windows Azure has to offer. Whether you need a development environment for your websites or mobiles app, running a virtual machine with your existing applications or simply putting a SQL database online. No worries, Windows Azure has the right packages available and the online management portal is really easy t handle. After this, we got a little bit more business oriented while Wasiim Hosenbocus, employee at Ceridian, took the attendees through the inerts of a real-life application, and demoed a couple of the existing features. He did a great job by showing how the different services of Windows Azure can be created and pulled together. After the lunch break it is always tough to keep the audience awake... And it was my turn. I gave a brief overview on operating and managing a SQL database on Windows Azure. Well, there are actually two options available and depending on your individual requirements you should be aware of both. The simpler version is called SQL Database and while provisioning only takes a couple of seconds, you should take into consideration that SQL Database has a number of constraints, like limitations on the actual database size - up to 5 GB as web edition and up to 150 GB maximum as business edition -, among others. Next, it was Chervine Bhiwoo's session on Windows Azure Mobile Services. It was absolutely amazing to see that the mobiles services directly offers you various project templates, like Windows 8 Store App, Android app, iOS app, and even Xamarin cross-platform app development. So, within a couple of minutes you can have your first mobile app active and running on Windows Azure. Furthermore, Chervine showed the attendees that adding another user interface, like Web Sites running on ASP.NET MVC 4 only takes a couple of minutes, too. And last but not least, we rounded up the day with Windows Azure Websites and hosting of Virtual Machines presented by some members of the local Microsoft Students Partners programme. Surely, one of the big advantages using Windows Azure is the availability of pre-defined installation packages of known web applications, like WordPress, Joomla!, or Ghost. Compared to running your own web site with a traditional web hoster it is surely en par, and depending on your personal level of expertise, Windows Azure provides you more liberty in terms of configuration than maybe a shared hosting environment. Running a pre-defined web application is one thing but in case that you would like to have more control over your hosting environment it is highly advised to opt for a virtual machine. Provisioning of an Ubuntu 12.04 LTS system was very simple to do but it takes some more minutes than you might expect. So, please be patient and take your time while Windows Azure gets everything in place for you. Afterwards, you can use a SecureShell (ssh) client like Putty in case of a Linux-based machine, or Remote Desktop Services when operating a Windows Server system to log in into your virtual machine. At the end of the day we had a great Q&A session and we finalised the event with our raffle of goodies. Participation in the raffle was bound to submission of the session survey and most gratefully we had a give-away for everyone. What a nice coincidence to finish of the day. Note: All session slides (and demo codes) will be made available on the MSCC event page. Please, check the Files section over there. (Some) Visual impressions from the event Just to give you an idea about what has happened during the GWAB 2014 at Ebene... Speakers and Microsoft Student Partners are getting ready for the Global Windows Azure Bootcamp 2014 GWAB 2014 attendees are fully integrated into the hands-on-labs and setting up their individuals cloud computing services 60 attendees at the GWAB 2014. Despite some technical difficulties we had a great time running the event GWAB 2014: Using the lunch break for networking and exchange of ideas - Great conversations and topics amongst attendees There are more pictures on the original event page: Questions & Answers Following are a couple of questions which have been asked and didn't get an answer during the event: Q: Is it possible to upload static pages via FTP? A: Yes, you can. Have a look at the right side column on the dashboard of your website. There you'll find information about the FTP and SFTP host names. You can use any FTP client, like ie. FileZilla to log in. FTP also gives you access to your log files. Q: What are the size limitations on SQL Database? A: 5 GB on the Web Edition, and 150 GB on the business edition. A maximum 150 databases (inclusing 'master') per SQL Database server. More details here: General Guidelines and Limitations (Azure SQL Database) Q: What's the maximum size of a SQL Server running in a Virtual Machine? A: The maximum Windows Azure VM has currently 8 CPU cores, 14 or 56 GB of RAM and 16x 1 TB hard drives. More details here: Virtual Machine and Cloud Service Sizes for Azure Q: How can we register for Windows Azure? A: Mauritius is currently not listed for phone verification. Please get in touch with Arnaud Meslier at Microsoft IOI & FP Q: Can I use my own domain name for Windows Azure websites? A: Yes, you can. But this might require to upscale your account to Standard. In case that I missed a question and answer, please use the comment section at the end of the article. Thanks! Final results Every participant was instructed during the hands-on-lab session on how to set up a cloud computing service in their account. Of course, I won't keep the results from you... Global Azure Lab GWAB 2014: Our cloud computing contribution to the research of diabetes And I would say Mauritius did a good job! Upcoming Events What are the upcoming events here in Mauritius? So far, we have the following ones (incomplete list as usual) in chronological order: Launch of Microsoft SQL Server 2014 (15.4.2014) Corsair Hackers Reboot (19.4.2014) WebCup (TBA ~ June 2014) Developers Conference (TBA ~ July 2014) Linuxfest 2014 (TBA ~ November 2014) Hopefully, there will be more announcements during the next couple of weeks and months. If you know about any other event, like a bootcamp, a code challenge or hackathon here in Mauritius, please drop me a note in the comment section below this article. Thanks! Networking and job/project opportunities Despite having technical presentations on Windows Azure an event like this always offers a great bunch of possibilities and opportunities to get in touch with new people in IT, have an exchange of experience with other like-minded people. As I already wrote about Communities - The importance of exchange and discussion - I had a great conversation with representatives of the University des Mascareignes which are currently embracing cloud infrastructure and cloud computing for their various campuses in the Indian Ocean. As for the MSCC it would be a great experience to stay in touch with them, and to work on upcoming, common activities. Furthermore, I had a very good conversation with Thierry and Ludovic of Microsoft IOI & FP on the necessity of user groups and IT communities here on the island. It's great to see that the MSCC is currently on a run and that local companies are sharing our thoughts on promoting IT careers and exchange of IT knowledge in such an open way. I'm also looking forward to be able to participate and to contribute on more events in the near future. My resume of the day We learned a lot today and there is always room for improvement! It was an awesome event and quite frankly it was a pleasure to spend the day with so many enthuastic IT people in the same room. It was a great experience to organise such event locally and participate on a global scale to support the GlyQ-IQ Technology in their research on diabetes. I was so pleased to see the involvement of new MSCC members in taking the opportunity to share and learn about the power of cloud computing. The Mauritius Software Craftsmanship Community is on the right way and this year's bootcamp on Windows Azure only marked the beginning of our journey. Thank you to our sponsors and my kudos to the MSPs! Update: Media coverage The event has been reported in local media, too. Following are some resources: Orange - Local - Business: Le cloud, pour des recherches approfondies sur le diabète Maurice Info.mu: Le cloud, pour des recherches approfondies sur le diabète Le Quotidien Pg 2: Global Windows Azure Bootcamp 2014 - Le cloud pour des recherches approfondies sur le diabète The Observer Pg 12: Le cloud, pour des recherches approfondies sur le diabète

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• How can I truncate an NSString to a set length?

  - by nevan

  I searched, but surprisingly couldn't find an answer. I have a long NSString that I want to shorten. I want the maximum length to be around 20 characters. I read somewhere that the best solution is to use substringWithRange. Is this the best way to truncate a string? NSRange stringRange = {0,20}; NSString *myString = @"This is a string, it's a very long string, it's a very long string indeed"; NSString *shortString = [myString substringWithRange:stringRange]; It seems a little delicate (crashes if the string is shorter than the maximum length). I'm also not sure if it's Unicode-safe. Is there a better way to do it? Does anyone have a nice category for this?

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• Detect an Uninstall in a Launch Condition using Wix MSIs

  - by coxymla

  I've been playing around with Wix, making a little app with auto-generated installer and three versions to test the upgradability, 1.0, 1.1 and 2.0. 1.1 is meant to be able to upgrade from 1.0, and not to allow the user to install 1.1 if 1.1 is already present. <Upgrade Id="F30C4129-F14E-43ee-BD5E-03AA89AD8E07"> <UpgradeVersion Minimum="1.0.0" IncludeMinimum="yes" Maximum="1.0.0" IncludeMaximum="yes" Property="OLDERVERSIONBEINGUPGRADED" /> <UpgradeVersion Minimum="1.1.0" IncludeMinimum="yes" OnlyDetect="yes" Property="NEWERVERSIONDETECTED" /> </Upgrade> <Condition Message="A later version of [ProductName] is already installed. Setup will now exit."> NOT (NEWERVERSIONDETECTED OR Installed) </Condition> Problem #1: 1.1 can't be uninstalled, because the condition is set and checked during the uninstall. 2.0 is meant to be able to upgrade from 1.1, and not to upgrade from 1.0 ('too old'.) It shouldn't be able to install on top of itself either. <Upgrade Id="F30C4129-F14E-43ee-BD5E-03AA89AD8E07"> <UpgradeVersion Minimum="1.1.0" IncludeMinimum="yes" Maximum="1.1.0" IncludeMaximum="yes" Property="OLDERVERSIONBEINGUPGRADED" /> </Upgrade> <Upgrade Id="F30C4129-F14E-43ee-BD5E-03AA89AD8E07"> <UpgradeVersion Minimum="2.0.0" OnlyDetect="yes" Property="NEWERVERSIONDETECTED" /> </Upgrade> <Upgrade Id="F30C4129-F14E-43ee-BD5E-03AA89AD8E07"> <UpgradeVersion Minimum="1.0.0" IncludeMinimum="yes" Maximum="1.0.0" IncludeMaximum="yes" Property="TOOOLDVERSIONDETECTED" /> </Upgrade> <Condition Message="A later version of [ProductName] is already installed. Setup will now exit."> NOT NEWERVERSIONDETECTED OR Installed </Condition> <Condition Message="A version of [ProductName] that is already installed is too old to be upgraded. Setup will now exit."> NOT TOOOLDVERSIONDETECTED </Condition> Problem #2: If I try to upgrade from 1.1, I hit my modified later version condition. (Error: A later version of Main Application 1.1 is already installed. Setup will now exit.) Problem #3: The installer allows me to install 2.0 over the top of itself. What am I doing wrong with my Upgrade code and conditions to get these problems in my MSIs?

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• Webkit iPhone App : How to dynamically change the user zoom (or scale, pich & zoom) in the viewport

  - by Samuel Michelot

  I use JQTouch for an iPhone app. JQtouch disable by default the possibility to pinch&zoom the page. For one page (containing a big image), i need to enable the pinch & zoom feature. This is easy : var viewport = $("head meta[name=viewport]"); viewport.attr('content', 'width=320, initial-scale=1, maximum-scale=10.0, minimum-scale=1, user-scalable=1'); But after user has play with the pinch & zoom, I need to dynamically reset the zoom (scale) to the default. I tried to reset the viewport: viewport.attr('content', 'width=320, initial-scale=1.0, maximum-scale=1.0, user-scalable=0;'); After calling the above code, it's not possible to zoom anymore (because of user-scalable=0;), but it doesn't change the current scale to the default. I am looking for something like setScale(1), or to change an attribute like current-scale=1 Any idea ?

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• Hide ticks at Min and Max in WPF Slider

  - by gehho

  Hi, I want to display a Slider ranging from 0.5 to 1.5 with only one tick mark at 1.0 to mark the center and default value. I have defined a Slider as follows: <Slider Minimum="0.5" Maximum="1.5" IsMoveToPointEnabled="True" IsSnapToTickEnabled="False" Orientation="Horizontal" Ticks="1.0" TickPlacement="BottomRight" Value="{Binding SomeProperty, Mode=TwoWay}"/> However, besides a tick mark at 0.0 this Slider also shows tick marks at 0.5 and 1.5, i.e. the Minimum and Maximum values. Is there a way to hide these min/max tick marks?! I checked all properties and tried changing some of them, but did not have success so far. Thanks, gehho.

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• Flex ProgressBar component problem

  - by Abhinav

  I am trying to use the ProgressBar Flex component inside a custom Actionscript 3.0 component derived from the UIComponent class. I have set the minimum and maximum values etc. _progressBar = new ProgressBar(); _progressBar.label = "Loading"; _progressBar.minimum = 0; _progressBar.maximum = 100; _progressBar.direction = ProgressBarDirection.RIGHT; _progressBar.mode = ProgressBarMode.MANUAL; The component shows the "Loading" text but not the loading bar. Anything like _progressBar.setProgress(20, 100) does not have any effect on the code. Any ideas why this is not working?

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• Salesforce/PHP - Bulk Outbound message (SOAP), Time out issue

  - by Phill Pafford

  Salesforce can send up to 100 requests inside 1 SOAP message. While sending this type of Bulk Ooutbound message request my PHP script finishes executing but SF fails to accept the ACK used to clear the message queue on the Salesforce side of things. Looking at the Outbound message log (monitoring) I see all the messages in a pending state with the Delivery Failure Reason "java.net.SocketTimeoutException: Read timed out". If my script has finished execution, why do I get this error? I have tried these methods to increase the execution time on my server as I have no access on the Salesforce side: set_time_limit(0); // in the script max_execution_time = 360 ; Maximum execution time of each script, in seconds max_input_time = 360 ; Maximum amount of time each script may spend parsing request data memory_limit = 32M ; Maximum amount of memory a script may consume I used the high settings just for testing. Any thoughts as to why this is failing the ACK delivery back to Salesforce? Here is some of the code: This is how I accept and send the ACK file for the imcoming SOAP request $data = 'php://input'; $content = file_get_contents($data); if($content) { respond('true'); } else { respond('false'); } The respond function function respond($tf) { $ACK = <<<ACK <?xml version = "1.0" encoding = "utf-8"?> <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <soapenv:Body> <notifications xmlns="http://soap.sforce.com/2005/09/outbound"> <Ack>$tf</Ack> </notifications> </soapenv:Body> </soapenv:Envelope> ACK; print trim($ACK); } These are in a generic script that I include into the script that uses the data for a specific workflow. I can process about 25 requests (That are in 1 SOAP response) but once I go over that I get the timeout error in the Salesforce queue. for 50 requests is usually takes my PHP script 86.77 seconds. Could it be Apache? PHP? I have also tested just accepting the 100 request SOAP response and just accepting and sending the ACK the queue clears out, so I know it's on my side of things. I show no errors in the apache log, the script runs fine. Thanks for any insight into this, --Phill

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• Searching a large list of words in another large list

  - by Christian

  I have a list of 1,000,000 strings with a maximum length of 256 with protein names. Every string has an associated ID. I have another list of 4,000,000,000 strings with a maximum length of 256 with words out of articles and every word has an ID. I want to find all matches between the list of protein names and the list of words of the articles. Which algorithm should I use? Should I use some prebuild API? It would be good if the algorithm runs on a normal PC without special hardware.

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• dynamic insert php mysql and preformance

  - by Ross

  I have a folder/array of images, it may be 1, maximum of 12. What I need to do is dynamically add them so the images are added to an images table. At the moment I have $directory = "portfolio_images/$id/Thumbs/"; $images = glob("" . $directory . "*.jpg"); for ( $i= 0; $i <= count($images); $i += 1) { mysql_query("INSERT INTO project_images (image_name, project_id)VALUES ('$images[0]', '$id')") or die(mysql_error()); } this is fine but it does not feel right, how is this for performance? Is there a better way? The maximum number of images is only ever going to be 12. Thanks, Ross

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• How can I bind a winforms Opacity to a TrackBar (slider)

  - by Allen

  I've got a winform with a BindingSource that has an int property named Opacity in its DataSource. I also have a TrackBar on the winform that I want to use to control the Opacity of the winform. I've bound the Value property on the TrackBar to the Opacity and that functions just fine, sliding the TrackBar will change the variable from TrackBar.Minimum (0) to TrackBar.Maximum (1). I've also bound the Opacity property of the winform to this value, however, since the TrackBar's values only go from Minimum to Maximum in +/-1 rather than +/- .1 or so (like Opacity does), it doesn't properly fade the winform. Instead, 0 will turn it opaque and 1 will turn it fully visible. I need a way to work within the architecture described above, but get the TrackBar to change its value from 0 to 1 in defined increments smaller than 1.

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• Bacula windows client could not connect to Bacula director

  - by pr0f-r00t

  I have a Bacula server on my Linux Debian squeeze host (Bacula version 5.0.2) and a Bacula client on Windows XP SP3. On my network each client can see each other, can share files and can ping. On my local server I could run bconsole and the server responds but when I run bconsole or bat on my windows client the server does not respond. Here are my configuration files: bacula-dir.conf: # # Default Bacula Director Configuration file # # The only thing that MUST be changed is to add one or more # file or directory names in the Include directive of the # FileSet resource. # # For Bacula release 5.0.2 (28 April 2010) -- debian squeeze/sid # # You might also want to change the default email address # from root to your address. See the "mail" and "operator" # directives in the Messages resource. # Director { # define myself Name = nima-desktop-dir DIRport = 9101 # where we listen for UA connections QueryFile = "/etc/bacula/scripts/query.sql" WorkingDirectory = "/var/lib/bacula" PidDirectory = "/var/run/bacula" Maximum Concurrent Jobs = 1 Password = "Cv70F6pf1t6pBopT4vQOnigDrR0v3L" # Console password Messages = Daemon DirAddress = 127.0.0.1 # DirAddress = 72.16.208.1 } JobDefs { Name = "DefaultJob" Type = Backup Level = Incremental Client = nima-desktop-fd FileSet = "Full Set" Schedule = "WeeklyCycle" Storage = File Messages = Standard Pool = File Priority = 10 Write Bootstrap = "/var/lib/bacula/%c.bsr" } # # Define the main nightly save backup job # By default, this job will back up to disk in /nonexistant/path/to/file/archive/dir Job { Name = "BackupClient1" JobDefs = "DefaultJob" } #Job { # Name = "BackupClient2" # Client = nima-desktop2-fd # JobDefs = "DefaultJob" #} # Backup the catalog database (after the nightly save) Job { Name = "BackupCatalog" JobDefs = "DefaultJob" Level = Full FileSet="Catalog" Schedule = "WeeklyCycleAfterBackup" # This creates an ASCII copy of the catalog # Arguments to make_catalog_backup.pl are: # make_catalog_backup.pl <catalog-name> RunBeforeJob = "/etc/bacula/scripts/make_catalog_backup.pl MyCatalog" # This deletes the copy of the catalog RunAfterJob = "/etc/bacula/scripts/delete_catalog_backup" Write Bootstrap = "/var/lib/bacula/%n.bsr" Priority = 11 # run after main backup } # # Standard Restore template, to be changed by Console program # Only one such job is needed for all Jobs/Clients/Storage ... # Job { Name = "RestoreFiles" Type = Restore Client=nima-desktop-fd FileSet="Full Set" Storage = File Pool = Default Messages = Standard Where = /nonexistant/path/to/file/archive/dir/bacula-restores } # job for vmware windows host Job { Name = "nimaxp-fd" Type = Backup Client = nimaxp-fd FileSet = "nimaxp-fs" Schedule = "WeeklyCycle" Storage = File Messages = Standard Pool = Default Write Bootstrap = "/var/bacula/working/rsys-win-www-1-fd.bsr" #Change this } # job for vmware windows host Job { Name = "arg-michael-fd" Type = Backup Client = nimaxp-fd FileSet = "arg-michael-fs" Schedule = "WeeklyCycle" Storage = File Messages = Standard Pool = Default Write Bootstrap = "/var/bacula/working/rsys-win-www-1-fd.bsr" #Change this } # List of files to be backed up FileSet { Name = "Full Set" Include { Options { signature = MD5 } # # Put your list of files here, preceded by 'File =', one per line # or include an external list with: # # File = <file-name # # Note: / backs up everything on the root partition. # if you have other partitions such as /usr or /home # you will probably want to add them too. # # By default this is defined to point to the Bacula binary # directory to give a reasonable FileSet to backup to # disk storage during initial testing. # File = /usr/sbin } # # If you backup the root directory, the following two excluded # files can be useful # Exclude { File = /var/lib/bacula File = /nonexistant/path/to/file/archive/dir File = /proc File = /tmp File = /.journal File = /.fsck } } # List of files to be backed up FileSet { Name = "nimaxp-fs" Enable VSS = yes Include { Options { signature = MD5 } File = "C:\softwares" File = C:/softwares File = "C:/softwares" } } # List of files to be backed up FileSet { Name = "arg-michael-fs" Enable VSS = yes Include { Options { signature = MD5 } File = "C:\softwares" File = C:/softwares File = "C:/softwares" } } # # When to do the backups, full backup on first sunday of the month, # differential (i.e. incremental since full) every other sunday, # and incremental backups other days Schedule { Name = "WeeklyCycle" Run = Full 1st sun at 23:05 Run = Differential 2nd-5th sun at 23:05 Run = Incremental mon-sat at 23:05 } # This schedule does the catalog. It starts after the WeeklyCycle Schedule { Name = "WeeklyCycleAfterBackup" Run = Full sun-sat at 23:10 } # This is the backup of the catalog FileSet { Name = "Catalog" Include { Options { signature = MD5 } File = "/var/lib/bacula/bacula.sql" } } # Client (File Services) to backup Client { Name = nima-desktop-fd Address = localhost FDPort = 9102 Catalog = MyCatalog Password = "_MOfxEuRzxijc0DIMcBqtyx9iW1tzE7V6" # password for FileDaemon File Retention = 30 days # 30 days Job Retention = 6 months # six months AutoPrune = yes # Prune expired Jobs/Files } # Client file service for vmware windows host Client { Name = nimaxp-fd Address = nimaxp FDPort = 9102 Catalog = MyCatalog Password = "Ku8F1YAhDz5EMUQjiC9CcSw95Aho9XbXailUmjOaAXJP" # password for FileDaemon File Retention = 30 days # 30 days Job Retention = 6 months # six months AutoPrune = yes # Prune expired Jobs/Files } # Client file service for vmware windows host Client { Name = arg-michael-fd Address = 192.168.0.61 FDPort = 9102 Catalog = MyCatalog Password = "b4E9FU6s/9Zm4BVFFnbXVKhlyd/zWxj0oWITKK6CALR/" # password for FileDaemon File Retention = 30 days # 30 days Job Retention = 6 months # six months AutoPrune = yes # Prune expired Jobs/Files } # # Second Client (File Services) to backup # You should change Name, Address, and Password before using # #Client { # Name = nima-desktop2-fd # Address = localhost2 # FDPort = 9102 # Catalog = MyCatalog # Password = "_MOfxEuRzxijc0DIMcBqtyx9iW1tzE7V62" # password for FileDaemon 2 # File Retention = 30 days # 30 days # Job Retention = 6 months # six months # AutoPrune = yes # Prune expired Jobs/Files #} # Definition of file storage device Storage { Name = File # Do not use "localhost" here Address = localhost # N.B. Use a fully qualified name here SDPort = 9103 Password = "Cj-gtxugC4dAymY01VTSlUgMTT5LFMHf9" Device = FileStorage Media Type = File } # Definition of DDS tape storage device #Storage { # Name = DDS-4 # Do not use "localhost" here # Address = localhost # N.B. Use a fully qualified name here # SDPort = 9103 # Password = "Cj-gtxugC4dAymY01VTSlUgMTT5LFMHf9" # password for Storage daemon # Device = DDS-4 # must be same as Device in Storage daemon # Media Type = DDS-4 # must be same as MediaType in Storage daemon # Autochanger = yes # enable for autochanger device #} # Definition of 8mm tape storage device #Storage { # Name = "8mmDrive" # Do not use "localhost" here # Address = localhost # N.B. Use a fully qualified name here # SDPort = 9103 # Password = "Cj-gtxugC4dAymY01VTSlUgMTT5LFMHf9" # Device = "Exabyte 8mm" # MediaType = "8mm" #} # Definition of DVD storage device #Storage { # Name = "DVD" # Do not use "localhost" here # Address = localhost # N.B. Use a fully qualified name here # SDPort = 9103 # Password = "Cj-gtxugC4dAymY01VTSlUgMTT5LFMHf9" # Device = "DVD Writer" # MediaType = "DVD" #} # Generic catalog service Catalog { Name = MyCatalog # Uncomment the following line if you want the dbi driver # dbdriver = "dbi:sqlite3"; dbaddress = 127.0.0.1; dbport = dbname = "bacula"; dbuser = ""; dbpassword = "" } # Reasonable message delivery -- send most everything to email address # and to the console Messages { Name = Standard # # NOTE! If you send to two email or more email addresses, you will need # to replace the %r in the from field (-f part) with a single valid # email address in both the mailcommand and the operatorcommand. # What this does is, it sets the email address that emails would display # in the FROM field, which is by default the same email as they're being # sent to. However, if you send email to more than one address, then # you'll have to set the FROM address manually, to a single address. # for example, a '[email protected]', is better since that tends to # tell (most) people that its coming from an automated source. # mailcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula: %t %e of %c %l\" %r" operatorcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula: Intervention needed for %j\" %r" mail = root@localhost = all, !skipped operator = root@localhost = mount console = all, !skipped, !saved # # WARNING! the following will create a file that you must cycle from # time to time as it will grow indefinitely. However, it will # also keep all your messages if they scroll off the console. # append = "/var/lib/bacula/log" = all, !skipped catalog = all } # # Message delivery for daemon messages (no job). Messages { Name = Daemon mailcommand = "/usr/lib/bacula/bsmtp -h localhost -f \"\(Bacula\) \<%r\>\" -s \"Bacula daemon message\" %r" mail = root@localhost = all, !skipped console = all, !skipped, !saved append = "/var/lib/bacula/log" = all, !skipped } # Default pool definition Pool { Name = Default Pool Type = Backup Recycle = yes # Bacula can automatically recycle Volumes AutoPrune = yes # Prune expired volumes Volume Retention = 365 days # one year } # File Pool definition Pool { Name = File Pool Type = Backup Recycle = yes # Bacula can automatically recycle Volumes AutoPrune = yes # Prune expired volumes Volume Retention = 365 days # one year Maximum Volume Bytes = 50G # Limit Volume size to something reasonable Maximum Volumes = 100 # Limit number of Volumes in Pool } # Scratch pool definition Pool { Name = Scratch Pool Type = Backup } # # Restricted console used by tray-monitor to get the status of the director # Console { Name = nima-desktop-mon Password = "-T0h6HCXWYNy0wWqOomysMvRGflQ_TA6c" CommandACL = status, .status } bacula-fd.conf on client: # # Default Bacula File Daemon Configuration file # # For Bacula release 5.0.3 (08/05/10) -- Windows MinGW32 # # There is not much to change here except perhaps the # File daemon Name # # # "Global" File daemon configuration specifications # FileDaemon { # this is me Name = nimaxp-fd FDport = 9102 # where we listen for the director WorkingDirectory = "C:\\Program Files\\Bacula\\working" Pid Directory = "C:\\Program Files\\Bacula\\working" # Plugin Directory = "C:\\Program Files\\Bacula\\plugins" Maximum Concurrent Jobs = 10 } # # List Directors who are permitted to contact this File daemon # Director { Name = Nima-desktop-dir Password = "Cv70F6pf1t6pBopT4vQOnigDrR0v3L" } # # Restricted Director, used by tray-monitor to get the # status of the file daemon # Director { Name = nimaxp-mon Password = "q5b5g+LkzDXorMViFwOn1/TUnjUyDlg+gRTBp236GrU3" Monitor = yes } # Send all messages except skipped files back to Director Messages { Name = Standard director = Nima-desktop = all, !skipped, !restored } I have checked my firewall and disabled the firewall but it doesn't work.

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• Help with password complexity regex

  - by Alex

  I'm using the following regex to validate password complexity: /^.*(?=.{6,12})(?=.*[0-9]{2})(?=.*[A-Z]{2})(?=.*[a-z]{2}).*$/ In a nutshell: 2 lowercase, 2 uppercase, 2 numbers, min length is 6 and max length is 12. It works perfectly, except for the maximum length, when I'm using a minimum length as well. For example: /^.*(?=.{6,})(?=.*[0-9]{2})(?=.*[A-Z]{2})(?=.*[a-z]{2}).*$/ This correctly requires a minimum length of 6! And this: /^.*(?=.{,12})(?=.*[0-9]{2})(?=.*[A-Z]{2})(?=.*[a-z]{2}).*$/ Correctly requires a maximum length of 12. However, when I pair them together as in the first example, it just doesn't work!! What gives? Thanks!

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• NULL handling with subselect in Hibernate Criteria API

  - by Jens Schauder

  I'm constructing a Hibernate Criterion, using a subselect as follows DetachedCriteria subselect = DetachedCriteria.forClass(NhmCode.class, "sub"); // the subselect selecting the maximum 'validFrom' subselect.add(Restrictions.le("validFrom", new Date())); // it should be in the past (null needs handling here) subselect.add(Property.forName("sub.lifeCycle").eqProperty("this.id")); // join to owning entity subselect.setProjection(Projections.max("validFrom")); // we are only interested in the maximum validFrom Conjunction resultCriterion = Restrictions.conjunction(); resultCriterion.add(Restrictions.ilike(property, value)); // I have other Restrictions as well resultCriterion.add(Property.forName("validFrom").eq(subselect)); // this fails when validFrom and the subselect return NULL return resultCriterion; It works ok so far, but the restriction on the last line before the return statement is false when validFrom and subselect result in NULL. What I need is a version which handles this case as true. Possibly by applying a NVL or coalesce or similar. How do I do this?

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• compare a string and trim in vb.net

  - by referr

  I have this string that shall come in from another file. The string has maximum length of 102 digits. I need to compare the string with numbers in a pair and delete those form that string. e.g - 6125223659587412563265... till 102 numbers that compare with this string- first set - 61 new string = 25223659587412563265 second set - 36 new string = 252259587412563265 and so on. the set of numbers shall go to maximum of 51 pairs = 102, which shall give an end result of string = "" How can i achieve this in a loop?

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• Do you still limit line length in code?

  - by Noldorin

  This is a matter on which I would like to gauge the opinion of the community: Do you still limit the length of lines of code to a fixed maximum? This was certainly a convention of the past for many languages; one would typically cap the number of characters per line to a value such as 80 (and more recnetly 100 or 120 I believe). As far as I understand, the primary reasons for limiting line length are: Readability - You don't have to scroll over horizontally when you want to see the end of some lines. Printing - Admittedly (at least in my experience), most code that you are working on does not get printed out on paper, but by limiting the number of characters you can insure that formatting doesn't get messed up when printed. Past editors (?) - Not sure about this one, but I suspect that at some point in the distant past of programming, (at least some) text editors may have been based on a fixed-width buffer. I'm sure there are points that I am still missing out, so feel free to add to these... Now, when I tend to observe C or C# code nowadays, I often see a number of different styles, the main ones being: Line length capped to 80, 100, or even 120 characters. As far as I understand, 80 is the traditional length, but the longer ones of 100 and 120 have appeared because of the widespread use of high resolutions and widescreen monitors nowadays. No line length capping at all. This tends to be pretty horrible to read, and I don't see it too often, though it's certainly not too rare either. Inconsistent capping of line length. The length of some lines are limited to a fixed maximum (or even a maximum that changes depending on the file/location in code), while others (possibly comments) are not at all. My personal preference here (at least recently) has been to cap the line length to 100 in the Visual Studio editor. This means that in a decently sized window (on a non-widescreen monitor), the ends of lines are still fully visible. I can however see a few disadvantages in this, especially when you end up writing code that's indented 3 or 4 levels and then having to include a long string literal - though I often take this as a sign to refactor my code! In particular, I am curious what the C and C# coders (or anyone who uses Visual Studio for that matter) think about this point, though I would be interested in hearing anyone's thoughts on the subject. Edit Thanks for the all answers - I appreciate the variety of opinions here, all presenting sound reasons. Consensus does seem to be tipping in the direction of always (or almost always) limit the line length. Interestingly, it seems to be in various coding standards to limit the line length. Judging by some of the answers, both the Python and Google CPP guidelines set the limit at 80 chars. I haven't seen anything similar regarding C# or VB.NET, but I would be curious to see if there are ones anywhere.

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• mysql medium int vs. int performance?

  - by aviv

  Hi, I have a simple users table, i guess the maximum users i am going to have is 300,000. Currently i am using: CREATE TABLE users ( id INT UNSIGEND AUTOINCEREMENT PRIMARY KEY, .... Of course i have many other tables that the users(id) is a FOREIGN KEY in them. I read that since the id is not going to use the full maximum of INT it is better to use: MEDIUMINT and it will give better performance. Is it true? (I am using mysql on Windows Server 2008) Thanks.

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• String Field Sizes for unicode database fields using different data access components

  - by Serg

  mjustin in his question 1 and question 2 says that TWideStringField.Size property for UTF8 fields in Delphi 2009 dbExpress is 4 times larger than the logical field size (max number of characters in the field). I inclined to consider this a dbExpress bug. That is what Delphi 2009 Help says: The interpretation of Size depends on the data type. The meaning of Size for data types that use it is given in the following table. For all other data types, Size is not used and its value is always 0. ftString - Size is the maximum number of characters in the string. I am using FibPlus 6.9.9 and it follows the above documentation - the string field size is the maximum number of characters, not bytes. So the question also implies the following question: Are DbExpress drivers in Delphi 2009 unusable for unicode databases?

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• Automating WebTrends analysis

  - by tridium

  Every week I access server logs processed by WebTrends (for about 7 profiles) and copy ad clickthrough and visitor information into Excel spreadsheets. A lot of it is just accessing certain sections and finding the right title and then copying the unique visitor information. I tried using WebTrends' built-in query tool but that is really poorly done (only uses a drag-and-drop system instead of text-based) and it has a maximum number of parameters and maximum length of queries to query with. As far as I know, the tools in WebTrends are not suitable to my purpose of automating the entire web metrics gathering process. I've gotten access to the raw server logs, but it seems redundant to parse that given that they are already being processed by WebTrends. To me it seems very scriptable, but how would I go about doing that? Is screen-scraping an option?

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• BigDecimal precision not persisted with javax.persistence annotations

  - by dkaczynski

  I am using the javax.persistence API and Hibernate to create annotations and persist entities and their attributes in an Oracle 11g Express database. I have the following attribute in an entity: @Column(precision = 12, scale = 9) private BigDecimal weightedScore; The goal is to persist a decimal value with a maximum of 12 digits and a maximum of 9 of those digits to the right of the decimal place. After calculating the weightedScore, the result is 0.1234, but once I commit the entity with the Oracle database, the value displays as 0.12. I can see this by either by using an EntityManager object to query the entry or by viewing it directly in the Oracle Application Express (Apex) interface in a web browser. How should I annotate my BigDecimal attribute so that the precision is persisted correctly? Note: We use an in-memory HSQL database to run our unit tests, and it does not experience the issue with the lack of precision, with or without the @Column annotation.

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• XML Output is Truncated in SQL

  - by Muhammad Akhtar

  Hi, I need to return my result set in XML and this works fine, but if the number of records are increased, my xml output is truncated here is my query select t.id,t.name,t.address from test FOR XML AUTO, ROOT('Response'), ELEMENTS However I have set some option to increase the output result set like.. Tools --> Options --> Query Results --> SQL Server --> Results to Text --> Maximum number of characters displayed in each column Tools --> Options --> Results --> Maximum characters per column but still I am unable to get my desired result. please suggest my solution Thanks....

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