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  • Getting Started with Columnstore Index in SQL Server 2014 – Part 1

    Column Store Index, which improves performance of data warehouse queries several folds, was first introduced in SQL Server 2012. In this article series Arshad Ali talks about how you can get started with using enhanced columnstore index features in SQL Server 2014 and do some performance tests to understand the benefits. Deployment Manager 2 is now free!The new version includes tons of new features and we've launched a completely free Starter Edition! Get Deployment Manager here

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  • SQLServerCentral Best Practices Clinic: Part 4

    In this next installment looking at implementing best practices here at SQLServerCentral, Brad McGehee looks at a few performance counters and what they tell us about the performance of our database server. The Future of SQL Server Monitoring "Being web-based, SQL Monitor enables you to check on your servers from almost any location" Jonathan Allen.Try SQL Monitor now.

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  • Windows Azure Virtual Machine Readiness and Capacity Assessment for SQL Server

    - by SQLOS Team
    Windows Azure Virtual Machine Readiness and Capacity Assessment for Windows Server Machine Running SQL Server With the release of MAP Toolkit 8.0 Beta, we have added a new scenario to assess your Windows Azure Virtual Machine Readiness. The MAP 8.0 Beta performs a comprehensive assessment of Windows Servers running SQL Server to determine you level of readiness to migrate an on-premise physical or virtual machine to Windows Azure Virtual Machines. The MAP Toolkit then offers suggested changes to prepare the machines for migration, such as upgrading the operating system or SQL Server. MAP Toolkit 8.0 Beta is available for download here Your participation and feedback is very important to make the MAP Toolkit work better for you. We encourage you to participate in the beta program and provide your feedback at [email protected] or through one of our surveys. Now, let’s walk through the MAP Toolkit task for completing the Windows Azure Virtual Machine assessment and capacity planning. The tasks include the following: Perform an inventory View the Windows Azure VM Readiness results and report Collect performance data for determine VM sizing View the Windows Azure Capacity results and report Perform an inventory: 1. To perform an inventory against a single machine or across a complete environment, choose Perform an Inventory to launch the Inventory and Assessment Wizard as shown below: 2. After the Inventory and Assessment Wizard launches, select either the Windows computers or SQL Server scenario to inventory Windows machines. HINT: If you don’t care about completely inventorying a machine, just select the SQL Server scenario. Click Next to Continue. 3. On the Discovery Methods page, select how you want to discover computers and then click Next to continue. Description of Discovery Methods: Use Active Directory Domain Services -- This method allows you to query a domain controller via the Lightweight Directory Access Protocol (LDAP) and select computers in all or specific domains, containers, or OUs. Use this method if all computers and devices are in AD DS. Windows networking protocols --  This method uses the WIN32 LAN Manager application programming interfaces to query the Computer Browser service for computers in workgroups and Windows NT 4.0–based domains. If the computers on the network are not joined to an Active Directory domain, use only the Windows networking protocols option to find computers. System Center Configuration Manager (SCCM) -- This method enables you to inventory computers managed by System Center Configuration Manager (SCCM). You need to provide credentials to the System Center Configuration Manager server in order to inventory the managed computers. When you select this option, the MAP Toolkit will query SCCM for a list of computers and then MAP will connect to these computers. Scan an IP address range -- This method allows you to specify the starting address and ending address of an IP address range. The wizard will then scan all IP addresses in the range and inventory only those computers. Note: This option can perform poorly, if many IP addresses aren’t being used within the range. Manually enter computer names and credentials -- Use this method if you want to inventory a small number of specific computers. Import computer names from a files -- Using this method, you can create a text file with a list of computer names that will be inventoried. 4. On the All Computers Credentials page, enter the accounts that have administrator rights to connect to the discovered machines. This does not need to a domain account, but needs to be a local administrator. I have entered my domain account that is an administrator on my local machine. Click Next after one or more accounts have been added. NOTE: The MAP Toolkit primarily uses Windows Management Instrumentation (WMI) to collect hardware, device, and software information from the remote computers. In order for the MAP Toolkit to successfully connect and inventory computers in your environment, you have to configure your machines to inventory through WMI and also allow your firewall to enable remote access through WMI. The MAP Toolkit also requires remote registry access for certain assessments. In addition to enabling WMI, you need accounts with administrative privileges to access desktops and servers in your environment. 5. On the Credentials Order page, select the order in which want the MAP Toolkit to connect to the machine and SQL Server. Generally just accept the defaults and click Next. 6. On the Enter Computers Manually page, click Create to pull up at dialog to enter one or more computer names. 7. On the Summary page confirm your settings and then click Finish. After clicking Finish the inventory process will start, as shown below: Windows Azure Readiness results and report After the inventory progress has completed, you can review the results under the Database scenario. On the tile, you will see the number of Windows Server machine with SQL Server that were analyzed, the number of machines that are ready to move without changes and the number of machines that require further changes. If you click this Azure VM Readiness tile, you will see additional details and can generate the Windows Azure VM Readiness Report. After the report is generated, select View | Saved Reports and Proposals to view the location of the report. Open up WindowsAzureVMReadiness* report in Excel. On the Windows tab, you can see the results of the assessment. This report has a column for the Operating System and SQL Server assessment and provides a recommendation on how to resolve, if there a component is not supported. Collect Performance Data Launch the Performance Wizard to collect performance information for the Windows Server machines that you would like the MAP Toolkit to suggest a Windows Azure VM size for. Windows Azure Capacity results and report After the performance metrics are collected, the Azure VM Capacity title will display the number of Virtual Machine sizes that are suggested for the Windows Server and Linux machines that were analyzed. You can then click on the Azure VM Capacity tile to see the capacity details and generate the Windows Azure VM Capacity Report. Within this report, you can view the performance data that was collected and the Virtual Machine sizes.   MAP Toolkit 8.0 Beta is available for download here Your participation and feedback is very important to make the MAP Toolkit work better for you. We encourage you to participate in the beta program and provide your feedback at [email protected] or through one of our surveys. Useful References: Windows Azure Homepage How to guides for Windows Azure Virtual Machines Provisioning a SQL Server Virtual Machine on Windows Azure Windows Azure Pricing     Peter Saddow Senior Program Manager – MAP Toolkit Team

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  • ubiquity "hangs" on first step

    - by bumbling fool
    Trying to install 11.04 daily for the last couple days but, no matter what I try (wifi connected, wifi not connected, disk blank, disk prepartitioned...), if just "hangs" at the first window (pick your language) with a non-stop hourglass after hitting next. I ran into a different issue when trying to use the alternate installer image. This is on a Stinkpad T42. Should ubiquity at least tell me whats going on?!? I tried to find a log but /var/log/installer* isn't present.

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  • Managing Data Growth in SQL Server

    'Help, my database ate my disk drives!'. Many DBAs spend most of their time dealing with variations of the problem of database processes consuming too much disk space. This happens because of errors such as incorrect configurations for recovery models, data growth for large objects and queries that overtax TempDB resources. Rodney describes, with some feeling, the errors that can lead to this sort of crisis for the working DBA, and their solution.

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  • Getting Started with Columnstored Index in SQL Server 2014 – Part 2

    Column Store Index, which improves performance of data warehouse queries several folds, was first introduced in SQL Server 2012. Though it had several limitations, now SQL Server 2014 enhances the columnstore index and overcomes several of the earlier limitations. In this article, Arshad Ali discusses how you can get started using the enhanced columnstore index feature in SQL Server 2014 and do some performance tests.

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  • Wrong statistics in AUX_STATS$ might puzzle the optimizer

    - by Mike Dietrich
    We do recommend the creation of System Statistics for quite a long time. Since Oracle 9i the optimizer works with a CPU and IO cost based model. And in order to give the optimizer some knowledge about the IO subsystem's performance and throughput - once System Statistics are collected - they'll get stored in AUX_STATS$. For this purpose in the old Oracle 9i days some default values had been defined - and you'll still find those defaults in Oracle Database 11g Release 2 in AUX_STATS$. But these old values don't reflect the performance of modern IO systems. So it might be a good best practice post upgrade to create fresh System Statistics if you haven't done this before.  You can collect System Statistics with: exec DBMS_STATS.GATHER_SYSTEM_STATS('start'); and end it later by executing: exec DBMS_STATS.GATHER_SYSTEM_STATS('stop'); You could also run DBMS_STATS.GATHER_SYSTEM_STATS('interval', interval=>N) instead where N is the number of minutes when statistics gathering is stopped automatically. Please make sure you'll do this on a real workload period. It won't make sense to gather these values while the database is in an idle state. You should do this ideally for several hours. It doesn't affect performance in a negative way as the values are anyway collected in V$SYSSTAT and V$SESSTAT. And in case you'd like to delete the stats and revert to the old default values you'd simply execute:exec DBMS_STATS.DELETE_SYSTEM_STATS; The tricky thing in Oracle Database 11.2 - and that's why I'm actually writing this blog post today - is bug9842771. This leads to wrong values in AUX_STATS$ for SREADTIM and MREADTIM by factor 1000 guiding the optimizer sometimes into the totally wrong directon. The workaround is to overwrite these values manually and divide them by 1000. Use the DBMS_STATS.SET_SYSTEM_STATS procedure. See this MOS Note:9842771.8 for the above bug for some further information. This issue is fixed in Oracle Database 11.2.0.3 and above. To get some background information about the statistics collected in please read this section in the Oracle Database 11.2 Performance Tuning Guide. And gathering System Statistics might have some implication if you have mixed workloads - and interacts with DB_FILE_MULTIBLOCK_READ_COUNT. For more information please read section 13.4.1.2.

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  • PowerPivot FILTER condition optimizations

    - by Marco Russo (SQLBI)
    In the comments of a recent post from Alberto Ferrari there was an interesting note about different performance related to the order of conditions in a FILTER call. I investigated about that and Jeffrey Wang has been so nice to give me some info about actual implementation that I can share on a blog post. First of all, an important disclaimer: PowerPivot is intended to make life easier, not requiring the user to think how to write the order of elements in a formula just to get better performance....(read more)

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  • Idera SQL Doctor 3.0 and MS SQL Changes

    New features worth mentioning in SQL doctor 3.0 begin with a new server dashboard that not only gives a comprehensive overview of a SQL Server instance's current health, but also several key details to help database administrators. Some of the details include recommendations on how to optimize server configuration, how to fix certain security issues, and how to get rid of performance bottlenecks. The latest version of SQL doctor also supplies users with key server information. The status of system parameters known to affect SQL Server performance, such as processes, disk partitions, cache, m...

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  • Crystal Reports: 3 New Uses For Sub Reports

    I hate sub reports and always consider them the last resort in any reporting solution. The negative effect on performance and maintainability is just not worth the easy ride they give the report writer. Nine times out of ten reporting requirements can be met using a little forethought and planning (and a solid understanding of formulas). With that said, there are a few novel ways of using sub reports which will not affect performance and actually prove a boon to the developer.

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  • Should I install ubuntu on USB instead of HDD dual-boot?

    - by user2147243
    I had Ubuntu 12.04 installed as dual-boot OS on top of Vista on my laptop. Hacked the grub settings to default to Vista (instead of the default Ubuntu -- pain) on startup, and all was OK for occasional Ubuntu use for past 6 months. Then last week I got a strange message about 'lack of disk space' (~50MB free) when installing pxyplot, even though there was still about 6GB free disk space when I checked later. Then today the Ubuntu wouldn't load at all, and checking the HDD partitions in Vista it looked like the 15GB Ubuntu partition was now three smaller partitions! So, I got rid of those partitions and expanded the Vista partition to use the reclaimed space. Now can't restart ('grub rescue' appears and doesn't 'rescue' anything), so I'll have to do a boot recovery using a Vista installation CD. (Not a particularly user-friendly failure mode of the dual-boot installation!) I now have to decide to either a) try installing ubuntu on the HDD again, but don't want to stuff up my Vista ever again, as that is my most used OS, or b) install Ubuntu on a 16GB USB 3.0 stick. Apparently performance from USB won't be as good as from HDD, and running OS from USB stick does lots of r/w so the stick may fail after a few years! Perhaps installing Ubuntu on live USB and setup to then run in RAM would alleviate the performance/USB lifespan problems? If I create a live-USB for Ubuntu OS, will it boot off that when I restart the laptop with it plugged in? Or will I have to change the laptop setting for boot-order whenever I want to boot Ubuntu instead of Vista (that would be even more painful than the grub default boot order putting Ubuntu ahead of the existing Vista OS!) -- update: I recovered my Vista setup using Iolo SystemMechanic Disaster Recovery Tool, and created a bootable USB of Ubuntu 13.10 on an 8GB USB3.0 pendrive, with 4GB of 'persistence' to allow saving of settings, install some packages etc. It worked OK for a couple of test boots, but once I changed the time and desktop wallpaper, the next Ubuntu reboot crashed and I then couldn't get it to boot successfully. So I decided to install Ubuntu 12.04 LTS as a dual-boot again, but this time instead of partitioning the HDD and installing from an ISO DVD I used the wubi.exe tool to install Ubuntu as a dual-boot. Worked very well, although one oddity was that, despite asking how big the make the partition (20GB), the installed Ubuntu appears to be happily installed somewhere within the Vista NTFS file system (no partition shows up in Windows disk manager, and in Ubuntu disk management tool the entire 133 GB of HDD is showing, with ~40GB free space). A nice feature of installing the dual-boot using wubi is that the laptop now uses Windows boot manager on startup, with Vista as the default OS and Ubuntu happily listed as second on the list. So far so good.

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  • Oracle Certification and virtualization Solutions.

    - by scoter
    As stated in official MOS ( My Oracle Support ) document 249212.1 support for Oracle products on non-Oracle VM platforms follow exactly the same stance as support for VMware and, so, the only x86 virtualization software solution certified for any Oracle product is "Oracle VM". Based on the fact that: Oracle VM is totally free ( you have the option to buy Oracle-Support ) Certified is pretty different from supported ( OracleVM is certified, others could be supported ) With Oracle VM you may not require to reproduce your issue(s) on physical server Oracle VM is the only x86 software solution that allows hard-partitioning *** *** see details to these Oracle public links: http://www.oracle.com/technetwork/server-storage/vm/ovm-hardpart-168217.pdf http://www.oracle.com/us/corporate/pricing/partitioning-070609.pdf people started asking to migrate from third party virtualization software (ex. RH KVM, VMWare) to Oracle VM. Migrating RH KVM guest to Oracle VM. OracleVM has a built-in P2V utility ( Official Documentation ) but in some cases we can't use it, due to : network inaccessibility between hypervisors ( KVM and OVM ) network slowness between hypervisors (KVM and OVM) size of the guest virtual-disks Here you'll find a step-by-step guide to "manually" migrate a guest machine from KVM to OVM. 1. Verify source guest characteristics. Using KVM web console you can verify characteristics of the guest you need to migrate, such as: CPU Cores details Defined Memory ( RAM ) Name of your guest Guest operating system Disks details ( number and size ) Network details ( number of NICs and network configuration ) 2. Export your guest in OVF / OVA format.  The export from Redhat KVM ( kernel virtual machine ) will create a structured export of your guest: [root@ovmserver1 mnt]# lltotal 12drwxrwx--- 5 36 36 4096 Oct 19 2012 b8296fca-13c4-4841-a50f-773b5139fcee b8296fca-13c4-4841-a50f-773b5139fcee is the ID of the guest exported from RH-KVM [root@ovmserver1 mnt]# cd b8296fca-13c4-4841-a50f-773b5139fcee/[root@ovmserver1 b8296fca-13c4-4841-a50f-773b5139fcee]# ls -ltrtotal 12drwxr-x--- 4 36 36 4096 Oct 19  2012 masterdrwxrwx--- 2 36 36 4096 Oct 29  2012 dom_mddrwxrwx--- 4 36 36 4096 Oct 31  2012 images images contains your virtual-disks exported [root@ovmserver1 b8296fca-13c4-4841-a50f-773b5139fcee]# cd images/[root@ovmserver1 images]# ls -ltratotal 16drwxrwx--- 5 36 36 4096 Oct 19  2012 ..drwxrwx--- 2 36 36 4096 Oct 31  2012 d4ef928d-6dc6-4743-b20d-568b424728a5drwxrwx--- 2 36 36 4096 Oct 31  2012 4b241ea0-43aa-4f3b-ab7d-2fc633b491a1drwxrwx--- 4 36 36 4096 Oct 31  2012 .[root@ovmserver1 images]# cd d4ef928d-6dc6-4743-b20d-568b424728a5/[root@ovmserver1 d4ef928d-6dc6-4743-b20d-568b424728a5]# ls -ltotal 5169092-rwxr----- 1 36 36 187904819200 Oct 31  2012 4c03b1cf-67cc-4af0-ad1e-529fd665dac1-rw-rw---- 1 36 36          341 Oct 31  2012 4c03b1cf-67cc-4af0-ad1e-529fd665dac1.meta[root@ovmserver1 d4ef928d-6dc6-4743-b20d-568b424728a5]# file 4c03b1cf-67cc-4af0-ad1e-529fd665dac14c03b1cf-67cc-4af0-ad1e-529fd665dac1: LVM2 (Linux Logical Volume Manager) , UUID: sZL1Ttpy0vNqykaPahEo3hK3lGhwspv 4c03b1cf-67cc-4af0-ad1e-529fd665dac1 is the first exported disk ( physical volume ) [root@ovmserver1 d4ef928d-6dc6-4743-b20d-568b424728a5]# cd ../4b241ea0-43aa-4f3b-ab7d-2fc633b491a1/[root@ovmserver1 4b241ea0-43aa-4f3b-ab7d-2fc633b491a1]# ls -ltotal 5568076-rwxr----- 1 36 36 107374182400 Oct 31  2012 9020f2e1-7b8a-4641-8f80-749768cc237a-rw-rw---- 1 36 36          341 Oct 31  2012 9020f2e1-7b8a-4641-8f80-749768cc237a.meta[root@ovmserver1 4b241ea0-43aa-4f3b-ab7d-2fc633b491a1]# file 9020f2e1-7b8a-4641-8f80-749768cc237a9020f2e1-7b8a-4641-8f80-749768cc237a: x86 boot sector; partition 1: ID=0x83, active, starthead 1, startsector 63, 401562 sectors; partition 2: ID=0x82, starthead 0, startsector 401625, 65529135 sectors; startsector 63, 401562 sectors; partition 2: ID=0x82, starthead 0, startsector 401625, 65529135 sectors; partition 3: ID=0x83, starthead 254, startsector 65930760, 8385930 sectors; partition 4: ID=0x5, starthead 254, startsector 74316690, 135395820 sectors, code offset 0x48 9020f2e1-7b8a-4641-8f80-749768cc237a is the second exported disk, with partition 1 bootable 3. Prepare the new guest on Oracle VM. By Ovm-Manager we can prepare the guest where we will move the exported virtual-disks; under the Tab "Servers and VMs": click on  and create your guest with parameters collected before (point 1): - add NICs on different networks: - add virtual-disks; in this case we add two disks of 1.0 GB each one; we will extend the virtual disk copying the source KVM virtual-disk ( see next steps ) - verify virtual-disks created ( under Repositories tab ) 4. Verify OVM virtual-disks names. [root@ovmserver1 VirtualMachines]# grep -r hyptest_rdbms * 0004fb0000060000a906b423f44da98e/vm.cfg:OVM_simple_name = 'hyptest_rdbms' [root@ovmserver1 VirtualMachines]# cd 0004fb0000060000a906b423f44da98e [root@ovmserver1 0004fb0000060000a906b423f44da98e]# more vm.cfgvif = ['mac=00:21:f6:0f:3f:85,bridge=0004fb001089128', 'mac=00:21:f6:0f:3f:8e,bridge=0004fb00101971d'] OVM_simple_name = 'hyptest_rdbms' vnclisten = '127.0.0.1' disk = ['file:/OVS/Repositories/0004fb00000300004f17b7368139eb41/ VirtualDisks/0004fb000012000097c1bfea9834b17d.img,xvda,w', 'file:/OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb0000120000cde6a11c3cb1d0be.img,xvdb,w'] vncunused = '1' uuid = '0004fb00-0006-0000-a906-b423f44da98e' on_reboot = 'restart' cpu_weight = 27500 memory = 32768 cpu_cap = 0 maxvcpus = 8 OVM_high_availability = True maxmem = 32768 vnc = '1' OVM_description = '' on_poweroff = 'destroy' on_crash = 'restart' name = '0004fb0000060000a906b423f44da98e' guest_os_type = 'linux' builder = 'hvm' vcpus = 8 keymap = 'en-us' OVM_os_type = 'Oracle Linux 5' OVM_cpu_compat_group = '' OVM_domain_type = 'xen_hvm' disk2 ovm ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb0000120000cde6a11c3cb1d0be.img disk1 ovm ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb000012000097c1bfea9834b17d.img Summarizing disk1 --source ==> /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/4b241ea0-43aa-4f3b-ab7d-2fc633b491a1/9020f2e1-7b8a-4641-8f80-749768cc237a disk1 --dest ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb000012000097c1bfea9834b17d.img disk2 --source ==> /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/d4ef928d-6dc6-4743-b20d-568b424728a5/4c03b1cf-67cc-4af0-ad1e-529fd665dac1 disk2 --dest ==> /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/ 0004fb0000120000cde6a11c3cb1d0be.img 5. Copy KVM exported virtual-disks to OVM virtual-disks. Keeping your Oracle VM guest stopped you can copy KVM exported virtual-disks to OVM virtual-disks; what I did is only to locally mount the filesystem containing the exported virtual-disk ( by an usb device ) on my OVS; the copy automatically resize OVM virtual-disks ( previously created with a size of 1GB ) . nohup cp /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/4b241ea0-43aa-4f3b-ab7d-2fc633b491a1/9020f2e1-7b8a-4641-8f80-749768cc237a /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/0004fb000012000097c1bfea9834b17d.img & nohup cp /mnt/b8296fca-13c4-4841-a50f-773b5139fcee/images/d4ef928d-6dc6-4743-b20d-568b424728a5/4c03b1cf-67cc-4af0-ad1e-529fd665dac1 /OVS/Repositories/0004fb00000300004f17b7368139eb41/VirtualDisks/0004fb0000120000cde6a11c3cb1d0be.img & 7. When copy completed refresh repository to aknowledge the new-disks size. 7. After "refresh repository" is completed, start guest machine by Oracle VM manager. After the first start of your guest: - verify that you can see all disks and partitions - verify that your guest is network reachable ( MAC Address of your NICs changed ) Eventually you can also evaluate to convert your guest to PVM ( Paravirtualized virtual Machine ) following official Oracle documentation. Ciao Simon COTER ps: next-time I'd like to post an article reporting how to manually migrate Virtual-Iron guests to OracleVM.  Comments and corrections are welcome. 

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  • 4.8M wasn't enough so we went for 5.055M tpmc with Unbreakable Enterprise Kernel r2 :-)

    - by wcoekaer
    We released a new set of benchmarks today. One is an updated tpc-c from a few months ago where we had just over 4.8M tpmc at $0.98 and we just updated it to go to 5.05M and $0.89. The other one is related to Java Middleware performance. You can find the press release here. Now, I don't want to talk about the actual relevance of the benchmark numbers, as I am not in the benchmark team. I want to talk about why these numbers and these efforts, unrelated to what they mean to your workload, matter to customers. The actual benchmark effort is a very big, long, expensive undertaking where many groups work together as a big virtual team. Having the virtual team be within a single company of course helps tremendously... We already start with a very big server setup with tons of storage, many disks, lots of ram, lots of cpu's, cores, threads, large database setups. Getting the whole setup going to start tuning, by itself, is no easy task, but then the real fun starts with tuning the system for optimal performance -and- stability. A benchmark is not just revving an engine at high rpm, it's actually hitting the circuit. The tests require long runs, require surviving availability tests, such as surviving crashes -and- recovery under load. In the TPC-C example, the x4800 system had 4TB ram, 160 threads (8 sockets, hyperthreaded, 10 cores/socket), tons of storage attached, tons of luns visible to the OS. flash storage, non flash storage... many things at high scale that all have to be perfectly synchronized. During this process, we find bugs, we fix bugs, we find performance issues, we fix performance issues, we find interesting potential features to investigate for the future, we start new development projects for future releases and all this goes back into the products. As more and more customers, for Oracle Linux, are running larger and larger, faster and faster, more mission critical, higher available databases..., these things are just absolutely critical. Unrelated to what anyone's specific opinion is about tpc-c or tpc-h or specjenterprise etc, there is a ton of effort that the customer benefits from. All this work makes Oracle Linux and/or Oracle Solaris better platforms. Whether it's faster, more stable, more scalable, more resilient. It helps. Another point that I always like to re-iterate around UEK and UEK2 : we have our kernel source git repository online. Complete changelog of the mainline kernel, and our changes, easy to pull, easy to dissect, easy to know what went in when, why and where. No need to go log into a website and manually click through pages to hopefully discover changes or patches. No need to untar 2 tar balls and run a diff.

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  • Java Hashed Collections

    The Java collections framework contains classes you use to maintain collections of other objects. These collection classes have different performance and ordering properties. See how the HashMap and HashSet Classes allow objects to be added to a collection, removed from a collection, or found in roughly constant time. Discover how to use these classes and what to do to achieve good performance from them.

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  • SIMD Extensions for the Database Storage Engine

    - by jchang
    For the last 15 years, Intel and AMD have been progressively adding special purpose extensions to their processor architectures. The extensions mostly pertain to vector operations with Single Instruction, Multiple Data (SIMD) concept. The reasoning was that achieving significant performance improvement over each successive generation for the general purpose elements had become extraordinarily difficult. On the other hand, SIMD performance could be significantly improved with special purpose registers...(read more)

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  • Getting started with tuning your SOA/BPM database using AWR

    - by Mark Nelson
    In order to continue to get good performance from your SOA or BPM 11g server, you will want to periodically check your database – the one you are storing your SOAINFRA schema in – to see if there are any performance issues there. This article provides a very brief introduction to the use of the Automatic Workload Repository (AWR) in the Oracle Database and what to look for in the reports for your SOA/BPM environment. READ MORE >>

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  • [Speaking] Presenting at AITP Region 18 IT Con

    - by AllenMWhite
    The IT Con event this Saturday, June 18, is an event similar to SQL Saturday. It has three tracks, an IT Professional track, a Development track and a Career Development track. I'll be presenting two sessions in the IT Professional track. Gather SQL Server Performance Data with PowerShell We all know how important it is to keep a baseline of performance metrics that allow us to know when something is wrong and help us to track it down and fix the problem. We don't always know how to do this easily...(read more)

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  • Raid1 with active and spare partition

    - by Daniel Baron
    I am having the following problem with a RAID1 software raid partition on my Ubuntu system (10.04 LTS, 2.6.32-24-server in case it matters). One of my disks (sdb5) reported I/O errors and was therefore marked faulty in the array. The array was then degraded with one active device. Hence, I replaced the harddisk, cloned the partition table and added all new partitions to my raid arrays. After syncing all partitions ended up fine, having 2 active devices - except one of them. The partition which reported the faulty disk before, however, did not include the new partition as an active device but as a spare disk: md3 : active raid1 sdb5[2] sda5[1] 4881344 blocks [2/1] [_U] A detailed look reveals: root@server:~# mdadm --detail /dev/md3 [...] Number Major Minor RaidDevice State 2 8 21 0 spare rebuilding /dev/sdb5 1 8 5 1 active sync /dev/sda5 So here is the question: How do I tell my raid to turn the spare disk into an active one? And why has it been added as a spare device? Recreating or reassembling the array is not an option, because it is my root partition. And I can not find any hints to that subject in the Software Raid HOWTO. Any help would be appreciated. Current Solution I found a solution to my problem, but I am not sure that this is the actual way to do it. Having a closer look at my raid I found that sdb5 was always listed as a spare device: mdadm --examine /dev/sdb5 [...] Number Major Minor RaidDevice State this 2 8 21 2 spare /dev/sdb5 0 0 0 0 0 removed 1 1 8 5 1 active sync /dev/sda5 2 2 8 21 2 spare /dev/sdb5 so readding the device sdb5 to the array md3 always ended up in adding the device as a spare. Finally I just recreated the array mdadm --create /dev/md3 --level=1 -n2 -x0 /dev/sda5 /dev/sdb5 which worked. But the question remains open for me: Is there a better way to manipulate the summaries in the superblock and to tell the array to turn sdb5 from a spare disk to an active disk? I am still curious for an answer.

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  • How do I maintain a really poorly written code base?

    - by onlineapplab.com
    Recently I got hired to work on existing web application because of NDA I'm not at liberty to disclose any details but this application is working online in sort of a beta testing stage before official launch. We have a few hundred users right now but this number is supposed to significantly increase after official launch. The application is written in PHP (but it is irrelevant to my question) and is running on a dual xeon processor standalone server with severe performance problems. I have seen a lot of bad PHP code but this really sets new standards, especially knowing how much time and money was invested in developing it. it is as badly coded as possible there is PHP, HTML, SQL mixed together and code is repeated whenever it is necessary (especially SQL queries). there are not any functions used, not mentioning any OOP there are four versions of the app (desktop, iPhone, Android + other mobile) each version has pretty much the same functionality but was created by copying the whole code base, so now there are some differences between each version and it is really hard to maintain the database is really badly designed, which is causing severe performance problems also for fixing some errors in PHP code there is a lot of database triggers used which are updating data on SELECT and on INSERT so any testing is a nightmare Basically, any sin of a bad programming you can imagine is there for example it is not only possible to use SQL injections in literally every place but you can log into app if you use a login which doesn't exist and an empty password. The team which created this app is not working on it any more and there is an outsourced team which suggested that there are some problems but was never willing to deal with the elephant in the room partially because they've got a very comfortable contract and partially due to lack of skills (just my opinion). My job was supposed to be fixing some performance problems and extending existing functionality but first thing I was asked to do was a review of the existing code base. I've made my review and it was quite a shock for the management but my conclusions were after some time finally confirmed by other programmers. Management made it clear that it is not possible to start rewriting this app from scratch (which in my opinion should be done). We have to maintain its operable state and at the same time fix performance errors and extend the functionality. My question is, as I don't want just to patch the existing code, how to transform this into properly written app while keeping the existing code working at the same time? My plan is: Unify four existing versions into common code base (fixing only most obvious errors). Redesign db and use triggers to populate it with data (so data will be maintained in two formats at the same time) All new functionality will be written as separate project. Step by step transfer existing functionality into the new project After some time everything will be in the new project Some explanation about #2, right now it is practically impossible to make any updates in existing db any change requires reviewing whole code and making changes in many places. Is such plan feasible at all? Another solution is to walk away and leave the headache to someone else.

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  • Organization &amp; Architecture UNISA Studies &ndash; Chap 4

    - by MarkPearl
    Learning Outcomes Explain the characteristics of memory systems Describe the memory hierarchy Discuss cache memory principles Discuss issues relevant to cache design Describe the cache organization of the Pentium Computer Memory Systems There are key characteristics of memory… Location – internal or external Capacity – expressed in terms of bytes Unit of Transfer – the number of bits read out of or written into memory at a time Access Method – sequential, direct, random or associative From a users perspective the two most important characteristics of memory are… Capacity Performance – access time, memory cycle time, transfer rate The trade off for memory happens along three axis… Faster access time, greater cost per bit Greater capacity, smaller cost per bit Greater capacity, slower access time This leads to people using a tiered approach in their use of memory   As one goes down the hierarchy, the following occurs… Decreasing cost per bit Increasing capacity Increasing access time Decreasing frequency of access of the memory by the processor The use of two levels of memory to reduce average access time works in principle, but only if conditions 1 to 4 apply. A variety of technologies exist that allow us to accomplish this. Thus it is possible to organize data across the hierarchy such that the percentage of accesses to each successively lower level is substantially less than that of the level above. A portion of main memory can be used as a buffer to hold data temporarily that is to be read out to disk. This is sometimes referred to as a disk cache and improves performance in two ways… Disk writes are clustered. Instead of many small transfers of data, we have a few large transfers of data. This improves disk performance and minimizes processor involvement. Some data designed for write-out may be referenced by a program before the next dump to disk. In that case the data is retrieved rapidly from the software cache rather than slowly from disk. Cache Memory Principles Cache memory is substantially faster than main memory. A caching system works as follows.. When a processor attempts to read a word of memory, a check is made to see if this in in cache memory… If it is, the data is supplied, If it is not in the cache, a block of main memory, consisting of a fixed number of words is loaded to the cache. Because of the phenomenon of locality of references, when a block of data is fetched into the cache, it is likely that there will be future references to that same memory location or to other words in the block. Elements of Cache Design While there are a large number of cache implementations, there are a few basic design elements that serve to classify and differentiate cache architectures… Cache Addresses Cache Size Mapping Function Replacement Algorithm Write Policy Line Size Number of Caches Cache Addresses Almost all non-embedded processors support virtual memory. Virtual memory in essence allows a program to address memory from a logical point of view without needing to worry about the amount of physical memory available. When virtual addresses are used the designer may choose to place the cache between the MMU (memory management unit) and the processor or between the MMU and main memory. The disadvantage of virtual memory is that most virtual memory systems supply each application with the same virtual memory address space (each application sees virtual memory starting at memory address 0), which means the cache memory must be completely flushed with each application context switch or extra bits must be added to each line of the cache to identify which virtual address space the address refers to. Cache Size We would like the size of the cache to be small enough so that the overall average cost per bit is close to that of main memory alone and large enough so that the overall average access time is close to that of the cache alone. Also, larger caches are slightly slower than smaller ones. Mapping Function Because there are fewer cache lines than main memory blocks, an algorithm is needed for mapping main memory blocks into cache lines. The choice of mapping function dictates how the cache is organized. Three techniques can be used… Direct – simplest technique, maps each block of main memory into only one possible cache line Associative – Each main memory block to be loaded into any line of the cache Set Associative – exhibits the strengths of both the direct and associative approaches while reducing their disadvantages For detailed explanations of each approach – read the text book (page 148 – 154) Replacement Algorithm For associative and set associating mapping a replacement algorithm is needed to determine which of the existing blocks in the cache must be replaced by a new block. There are four common approaches… LRU (Least recently used) FIFO (First in first out) LFU (Least frequently used) Random selection Write Policy When a block resident in the cache is to be replaced, there are two cases to consider If no writes to that block have happened in the cache – discard it If a write has occurred, a process needs to be initiated where the changes in the cache are propagated back to the main memory. There are several approaches to achieve this including… Write Through – all writes to the cache are done to the main memory as well at the point of the change Write Back – when a block is replaced, all dirty bits are written back to main memory The problem is complicated when we have multiple caches, there are techniques to accommodate for this but I have not summarized them. Line Size When a block of data is retrieved and placed in the cache, not only the desired word but also some number of adjacent words are retrieved. As the block size increases from very small to larger sizes, the hit ratio will at first increase because of the principle of locality, which states that the data in the vicinity of a referenced word are likely to be referenced in the near future. As the block size increases, more useful data are brought into cache. The hit ratio will begin to decrease as the block becomes even bigger and the probability of using the newly fetched information becomes less than the probability of using the newly fetched information that has to be replaced. Two specific effects come into play… Larger blocks reduce the number of blocks that fit into a cache. Because each block fetch overwrites older cache contents, a small number of blocks results in data being overwritten shortly after they are fetched. As a block becomes larger, each additional word is farther from the requested word and therefore less likely to be needed in the near future. The relationship between block size and hit ratio is complex, and no set approach is judged to be the best in all circumstances.   Pentium 4 and ARM cache organizations The processor core consists of four major components: Fetch/decode unit – fetches program instruction in order from the L2 cache, decodes these into a series of micro-operations, and stores the results in the L2 instruction cache Out-of-order execution logic – Schedules execution of the micro-operations subject to data dependencies and resource availability – thus micro-operations may be scheduled for execution in a different order than they were fetched from the instruction stream. As time permits, this unit schedules speculative execution of micro-operations that may be required in the future Execution units – These units execute micro-operations, fetching the required data from the L1 data cache and temporarily storing results in registers Memory subsystem – This unit includes the L2 and L3 caches and the system bus, which is used to access main memory when the L1 and L2 caches have a cache miss and to access the system I/O resources

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  • Windows Server 2008 Software Raid 5 - Data integrity issues

    - by Fopedush
    I've got a server running Windows Server 2008 R2, with a (windows native) software raid-5 array. The array consists of 7x 1TB Western Digital RE3 and RE4 drives. I have offline backups of this array. The problem is this: I noticed a few days ago after copying a large file to the disk that there was an integrity issue with that file - it was a ~12GB file that I had downloaded via uTorrent. After moving it to the raid array, I used uTorrent to relocate the download location, and performed a re-check so I could seed it from that location. The recheck found that only 6308/6310 chunks of the copied file were intact. My next step was to write a quick powershell script that would copy files to the array, while performing a SHA1 hash of the original and resultant files and comparing them. Smaller files (100-1000MB) copied over just fine. When I started copying larger data (~15GB), I found that the hash check failed about 2/3rds of the time. The corrupt files had very, very small inconsistencies - less than .01%. I further eliminated the possibility of networking or client issues by placing this large file on the C:\ of the server, and copying it repeatedly from there to the array, seeing similar results. Copying the data via explorer, powershell, or the standard windows command prompt yield the same results. None of the copies fail or report any problems. The raid array itself is listed as healthy in disk management. After a few experiments, I shut down the server and ran memtest overnight. No errors were detected. A basic run of chkdsk found no problems, but I did not use the /R flag, as I was unsure how that might affect a software raid-5 volume. I next ran Crystal Disk Info to check the smart data on the drives - but found that CDI only detected 5 out of 7 of the disks in the array. I have no idea why. Nevertheless, CDI shows the following "caution" flags on a single one of the drives: 05 199 199 140 000000000001 Reallocated Sectors Count C5 200 200 __0 000000000001 Current Pending Sector Count Which is a little bit alarming, but I don't really know what to do with the information. I hardly feel like one reallocated sector could be causing this. At this point, I'm looking for some guidance on what to do next. I need to determine the cause of this issue, but I'm hesitant to run chkdsk /R or any bootable disk health checkers because I'm afraid they might break the array. I've considered triggering a re-sync of the array, but I'm not actually sure how to do that without doing something silly like manually dropping a disk and then restoring it. Any advice that could help me ferret out the precise cause of this issue would be greatly appreciated.

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  • Is it recommended to apply the new said-great 200 line Linux kernel path to Ubuntu?

    - by takpar
    Hi, Nowadays I'm hearing a lot about the new ~200 line path to Linux kernel that is said makes sensible difference in performance. Now, do anyone has experience on applying this path on his Ubuntu kernel? I also saw an alternative way that claimed has a better result: wget http://launchpadlibrarian.net/59511828/cgroup_patch chmod +x cgroup_patch sudo ./cgroup_patch What do you think this is? Is this validated? I ask this question because I need more performance but I can't risk on stability.

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  • Improving Finance Department Productivity at BorgWarner

    Nigel Youell, Product Marketing Director, Enterprise Performance Management Applications at Oracle discusses with Mark Smith, Manager, Financial Reporting Systems at BorgWarner how using Oracle's Enterprise Performance Management System on top of SAP transactional systems at BorgWarner has made significant improvements in the productivity of it finance function and halved the time it takes for to close its books.

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  • PowerPivot FILTER condition optimizations

    - by Marco Russo (SQLBI)
    In the comments of a recent post from Alberto Ferrari there was an interesting note about different performance related to the order of conditions in a FILTER call. I investigated about that and Jeffrey Wang has been so nice to give me some info about actual implementation that I can share on a blog post. First of all, an important disclaimer: PowerPivot is intended to make life easier, not requiring the user to think how to write the order of elements in a formula just to get better performance....(read more)

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  • How Oracle GRC Applications Improve the Bottom Line

    By spotting anomalies before they incur large losses and limiting exposure to fraud and wastage, organizations save on time and cost spent on errors and remediation, prevent the escalation of risk, and optimize business performance. The session will unveil the latest capabilities offered by Oracle's GRC Applications that help companies grow from managing compliance to optimizing business performance.

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