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  • Memory read/write access efficiency

    - by wolfPack88
    I've heard conflicting information from different sources, and I'm not really sure which one to believe. As such, I'll post what I understand and ask for corrections. Let's say I want to use a 2D matrix. There are three ways that I can do this (at least that I know of). 1: int i; char **matrix; matrix = malloc(50 * sizeof(char *)); for(i = 0; i < 50; i++) matrix[i] = malloc(50); 2: int i; int rowSize = 50; int pointerSize = 50 * sizeof(char *); int dataSize = 50 * 50; char **matrix; matrix = malloc(dataSize + pointerSize); char *pData = matrix + pointerSize - rowSize; for(i = 0; i < 50; i++) { pData += rowSize; matrix[i] = pData; } 3: //instead of accessing matrix[i][j] here, we would access matrix[i * 50 + j] char *matrix = malloc(50 * 50); In terms of memory usage, my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient, for the reasons below: 3: There is only one pointer and one allocation, and therefore, minimal overhead. 2: Once again, there is only one allocation, but there are now 51 pointers. This means there is 50 * sizeof(char *) more overhead. 1: There are 51 allocations and 51 pointers, causing the most overhead of all options. In terms of performance, once again my understanding is that 3 is the most efficient, 2 is next, and 1 is least efficient. Reasons being: 3: Only one memory access is needed. We will have to do a multiplication and an addition as opposed to two additions (as in the case of a pointer to a pointer), but memory access is slow enough that this doesn't matter. 2: We need two memory accesses; once to get a char *, and then to the appropriate char. Only two additions are performed here (once to get to the correct char * pointer from the original memory location, and once to get to the correct char variable from wherever the char * points to), so multiplication (which is slower than addition) is not required. However, on modern CPUs, multiplication is faster than memory access, so this point is moot. 1: Same issues as 2, but now the memory isn't contiguous. This causes cache misses and extra page table lookups, making it the least efficient of the lot. First and foremost: Is this correct? Second: Is there an option 4 that I am missing that would be even more efficient?

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  • Issues with LVM partition size in Server 13.04

    - by Michael
    I am new to ubuntu and a little confused about how hard drive partitions and LVM works. I remember setting up Ubuntu server 13.04 and telling to to use 1TB of a 3TB server. Well I have maxed that out with blu-ray rips and want the rest of the drive for space. On log-in it says: System load: 2.24 Processes: 179 Usage of /: 88.7% of 912.89GB Users logged in: 0 Memory usage: 6% IP address for p5p1: 192.168.0.100 Swap usage: 0% => / is using 88.7% of 912.89GB lvdisplay outputs: --- Logical volume --- LV Path /dev/DeathStar-vg/root LV Name root VG Name DeathStar-vg LV Write Access read/write LV Creation host, time DeathStar, 2013-05-18 22:21:11 -0400 LV Status available # open 1 LV Size 2.70 TiB Current LE 707789 Segments 2 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 252:0 --- Logical volume --- LV Path /dev/DeathStar-vg/swap_1 LV Name swap_1 VG Name DeathStar-vg LV Write Access read/write LV Creation host, time DeathStar, 2013-05-18 22:21:11 -0400 LV Status available # open 2 LV Size 3.75 GiB Current LE 959 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 252:1 vgdisplay outputs: VG Name DeathStar-vg System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size 2.73 TiB PE Size 4.00 MiB Total PE 715335 Alloc PE / Size 708748 / 2.70 TiB Free PE / Size 6587 / 25.73 GiB df outputs: Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/DeathStar--vg-root 957238932 848972636 59634696 94% / none 4 0 4 0% /sys/fs/cgroup udev 1864716 4 1864712 1% /dev tmpfs 374968 1060 373908 1% /run none 5120 4 5116 1% /run/lock none 1874824 148 1874676 1% /run/shm none 102400 24 102376 1% /run/user /dev/sda2 234153 56477 165184 26% /boot And fdisk /dev/sda -l outputs: Disk /dev/sda: 3000.6 GB, 3000592982016 bytes 255 heads, 63 sectors/track, 364801 cylinders, total 5860533168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 4096 bytes I/O size (minimum/optimal): 4096 bytes / 4096 bytes Disk identifier: 0x00000000 Device Boot Start End Blocks Id System /dev/sda1 1 4294967295 2147483647+ ee GPT Partition 1 does not start on physical sector boundary. I just don't know what to make of all this and am not sure how I can make it use all 2.73TBs. Thanks in advance for any help. EDIT-- Yes I did make changes to the LVM Config, but it didnt do anything. As requested, output of parted -l /dev/sda Model: ATA WDC WD30EFRX-68A (scsi) Disk /dev/sda: 3001GB Sector size (logical/physical): 512B/4096B Partition Table: gpt Number Start End Size File system Name Flags 1 1049kB 2097kB 1049kB bios_grub 2 2097kB 258MB 256MB ext2 3 258MB 3001GB 3000GB lvm Model: ATA WDC WD30EFRX-68A (scsi) Disk /dev/sdb: 3001GB Sector size (logical/physical): 512B/4096B Partition Table: msdos Number Start End Size Type File system Flags Model: Linux device-mapper (linear) (dm) Disk /dev/mapper/DeathStar--vg-swap_1: 4022MB Sector size (logical/physical): 512B/4096B Partition Table: loop Number Start End Size File system Flags 1 0.00B 4022MB 4022MB linux-swap(v1) Model: Linux device-mapper (linear) (dm) Disk /dev/mapper/DeathStar--vg-root: 2969GB Sector size (logical/physical): 512B/4096B Partition Table: loop Number Start End Size File system Flags 1 0.00B 2969GB 2969GB ext4

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  • I get GL_INVALID_VALUE after calling glTexSubImage2D

    - by user892644
    I am trying to figure out why my texture allocation does not work. Here is the code: glTexStorage2D(GL_TEXTURE_2D, 2, GL_RGBA8, 2048, 2048); glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 2048, 2048, GL_RGB, GL_UNSIGNED_SHORT_5_6_5_REV, &BitMap[0]); glTexSubImage2D returns GL_INVALID_VALUE but the maximum texture allowed is 16384x16384 on my card. The source of the image is 16bit (Red 5, Green 6, Blue 5).

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  • Temporary Object Caching Explained

    - by Paul White
    SQL Server 2005 onward caches temporary tables and table variables referenced in stored procedures for reuse, reducing contention on tempdb allocation structures and catalogue tables.  A number of things can prevent this caching (none of which are allowed when working with table variables): Named constraints (bad idea anyway, since concurrent executions can cause a name collision) DDL after creation (though what is considered DDL is interesting) Creation using dynamic SQL Table created in a...(read more)

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  • SQL Server Memory Manager Changes in Denali

    - by SQLOS Team
    The next version of SQL Server will contain significant changes to the memory manager component.  The memory manager component has been rewritten for Denali.  In the previous versions of SQL Server there were two distinct memory managers.  There was one memory manager which handled allocation sizes of 8k or less and another for greater than 8k.  For Denali there will be one memory manager for all allocation sizes.   The majority of the changes will be transparent to the end user.  However, some changes will be visible to the user.  These are listed below: ·         The ‘max server memory’ configuration option has new lower limits.  Specifically, 32-bit versions of SQL Server will have a lower limit of 64 MB.  The 64-bit versions will have a lower limit of 128 MB. ·         All memory allocations by SQL Server components will observe the ‘max server memory’ configuration option.  In previous SQL versions only the 8k allocations were limited the ‘max server memory’ configuration option.  Allocations larger than 8k weren’t constrained. ·         DMVs which refer to memory manager internals have been modified.  This includes adding or removing columns and changing column names. ·         The memory manager configuration messages in the error log have minor changes. ·         DBCC memorystatus output has been changed. ·         Address Windowing Extensions (AWE) has been deprecated.   In the next blog post I will discuss the changes to the memory manager DMVs in greater detail.  In future blog posts I will discuss the other changes in greater detail.  

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  • What Instruments Does a Web Based Project Management System Offer Us?

    Nowadays, in order to successfully manage various and complex projects, a project owner has access to a multitude of web based software covering key areas of focus such as scheduling, cost control, budget management, resource allocation, documentation and communication. Managing projects becomes time and resource saving also maximizing collaboration between team members that, in certain situations must stay connected to the partial outcomes.

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  • Samsung crée F2FS, un nouveau système de fichiers open source pour mémoire Flash qui sera intégré au noyau Linux

    Samsung crée F2FS son nouveau système de fichiers open source pour mémoire flash qui sera intégré au noyau Linux Samsung a mis au point un nouveau système de fichiers destiné aux supports de stockage flash. Les systèmes de fichiers anciens qui sont actuellement utilisés pour le stockage sur les mémoires flash NAND très répandues sur les terminaux mobiles présentent des limites assez importantes. Certains constructeurs de smartphones comme RIM ou encore Sharp ont été obligés de se tourner vers le système de fichiers propriétaire Extended File Allocation Table (exFAT) de Microsoft contre payement de redevances.

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  • Imagemagick PDF to JPG conversion failing

    - by Scott
    I'm trying to convert the first page of a PDF to a JPG. I'm pretty sure I got this to work with certain PDFs, but is it really possible that certain PDFs are made incorrectly and cannot be converted? I tried running this first: $ convert 10-03-26.pdf[1] test.jpg And I got the follow: Error: /syntaxerror in readxref Operand stack: Execution stack: %interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 1 3 %oparray_pop 1 3 %oparray_pop --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- Dictionary stack: --dict:1062/1417(ro)(G)-- --dict:0/20(G)-- --dict:73/200(L)-- --dict:73/200(L)-- --dict:97/127(ro)(G)-- --dict:229/230(ro)(G)-- --dict:14/15(L)-- Current allocation mode is local ESP Ghostscript 7.07.1: Unrecoverable error, exit code 1 convert: Postscript delegate failed `10-03-26.pdf'. Running this instead: $ convert -verbose -colorspace rgb '10-03-26.pdf[1]' test.jpg I get the following: Error: /syntaxerror in readxref Operand stack: Execution stack: %interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 1 3 %oparray_pop 1 3 %oparray_pop --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- Dictionary stack: --dict:1062/1417(ro)(G)-- --dict:0/20(G)-- --dict:73/200(L)-- --dict:73/200(L)-- --dict:97/127(ro)(G)-- --dict:229/230(ro)(G)-- --dict:14/15(L)-- Current allocation mode is local ESP Ghostscript 7.07.1: Unrecoverable error, exit code 1 "gs" -q -dBATCH -dSAFER -dMaxBitmap=500000000 -dNOPAUSE -dAlignToPixels=0 "-sDEVICE=pnmraw" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-g792x1611" "-r72x72" -dFirstPage=2 -dLastPage=2 "-sOutputFile=/tmp/magick-XXU3T44P" "-f/tmp/magick-XXoMKL8Z" "-f/tmp/magic2eec1F"Start of Image Define Huffman Table 0x00 0 1 5 1 1 1 1 1 1 0 0 0 0 0 0 0 Define Huffman Table 0x01 0 3 1 1 1 1 1 1 1 1 1 0 0 0 0 0 Define Huffman Table 0x10 0 2 1 3 3 2 4 3 5 5 4 4 0 0 1 125 Define Huffman Table 0x11 0 2 1 2 4 4 3 4 7 5 4 4 0 1 2 119 End Of Image convert: Postscript delegate failed `10-03-26.pdf'. Why would the conversion fail? Just as an aside, this is happening on a (gs) Grid-Service on (mt) Media Temple hosting. I cannot install programs on the server, but both Imagemagick and Ghostscript are installed Thanks!

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  • Xen hipervisor 4.1 Kernel Panic on Ubuntu 12.04

    - by rkmax
    I have a fresh Ubuntu 12.04.1 amd64 server install following this guide I have used LVM option used all disk and make 2 LV /dev/mapper/vg-root / (80GB) vg-swap swap (4GB) now i install xen with apt-get install xen-hypervisor-4.1-amd64 and config /etc/default/grub like the guide and add GRUB_CMDLINE_XEN_DEFAULT="dom0_mem=768M" later all this i exec update-grub and reboot. but when i try to boot with Xen 4.1-amd64 always i get a kernel panic with the message Domain-0 allocation is too small for kernel image my questions are: this error is about what? where i can grow this allocation for avoid this error? grub.cfg menuentry 'Ubuntu GNU/Linux, with Xen 4.1-amd64 and Linux 3.2.0-29-generic' --class ubuntu --class gnu-linux --class gnu --class os --class xen { insmod part_gpt insmod ext2 set root='(hd0,gpt2)' search --no-floppy --fs-uuid --set=root 3541e241-7f39-4ebe-8d99-c5306294c266 echo 'Loading Xen 4.1-amd64 ...' multiboot /xen-4.1-amd64.gz placeholder dom0_mem=768M echo 'Loading Linux 3.2.0-29-generic ...' module /vmlinuz-3.2.0-29-generic placeholder root=/dev/mapper/backup--xen-root ro rootdelay=180 echo 'Loading initial ramdisk ...' module /initrd.img-3.2.0-29-generic } Note: I've followed this guide too

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  • Getting an error when mounting LVM snapshot

    - by Sandra
    I have migrated a file based Xen guest to LVM using dd bs=1M if=/dev/zero of=/dev/vg00/vm10 qemu-img convert ~/vm10.qcow2 -O raw /dev/vg00/vm10 and changed the Xen domain file for the VM to use the LV instead of the old file. The VM boots up, and now on the Xen host would I like to make a snapshot of the running VM. # lvcreate --size 10G --snapshot --name vm10-snapshot /dev/vg00/vm10 Logical volume "vm10-snapshot" created # mount /dev/vg00/vm10-snapshot /mnt/snapshot/ mount: you must specify the filesystem type # dmesg |tail EXT3 FS on dm-3, internal journal EXT3-fs: mounted filesystem with ordered data mode. hfs: unable to find HFS+ superblock VFS: Can't find ext3 filesystem on dev dm-4. hfs: unable to find HFS+ superblock hfs: unable to find HFS+ superblock VFS: Can't find ext3 filesystem on dev dm-2. hfs: unable to find HFS+ superblock hfs: unable to find HFS+ superblock hfs: unable to find HFS+ superblock For some reason it can't see it is an EXT3 filesystem. I have also tried to mount with -t ext3, but still didn't mount. # lvdisplay --- Logical volume --- LV Name /dev/vg00/vm10 VG Name vg00 LV UUID I1y1vQ-Bac5-5jwW-melh-TY5h-l9NO-qaelKk LV Write Access read/write LV snapshot status source of /dev/vg00/vm10-snapshot [active] LV Status available # open 2 LV Size 8.00 GB Current LE 2048 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:2 --- Logical volume --- LV Name /dev/vg00/vm10-snapshot VG Name vg00 LV UUID GWsOx3-TPpr-GW64-uiMz-u1YN-QU4h-l0Kala LV Write Access read/write LV snapshot status active destination for /dev/vg00/vm10 LV Status available # open 0 LV Size 8.00 GB Current LE 2048 COW-table size 10.00 GB COW-table LE 2560 Allocated to snapshot 0.00% Snapshot chunk size 4.00 KB Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:4 # What could the problem be?

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  • 16TB Volumes and SNMP On Windows

    - by John K
    As volumes larger than 16TB became more common, it was recognized that the 32 bit value used to report disk size and usage within the standard "HOST-RESOURCES" MIB in SNMP was not large enough to report the proper disk size. Net-SNMP seems to have addressed this issue by simply manipulating the value of "AllocationUnits" to maintain a 32 bit value for disk utilization (since total disk size/usage is equal to the 32 bit space value times the allocation unit), to allow for the calculation of a volume larger than 8/16TB. Presuming you don't have any reporting interest in the allocation unit, this seems like a fine solution. https://bugzilla.redhat.com/show_bug.cgi?id=654384 Window's built in SNMP service, however, seems to continue to suffer from this error, simply reporting the modulo of the used/assigned disk space, resulting in inaccurate disk size reporting. Is there a way to enable Windows to correctly report disk usage for volumes over 16TB? We attempted to simply install Net-SNMP 5.5 x64 and disable Windows SNMP service entirely, however this unfortunately did not fix our issue. I've seen people in the Cacti community mention simply scripting out a solution. Unfortunately, we're using Observium for quick and basic systems monitoring. If the issue can't be correct on the Window's side, can Observium be made to report custom MIBs?

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  • Extending ext4 partition on debian7.0 on vsphere

    - by VoidPointer
    I have allocated thin provisioning of 15GB when i found 8GB as insufficient. Now debian guest is not able to recognize the change of size. root@debian7-x64:~# lvdisplay --- Logical volume --- LV Path /dev/debian7-x64/root LV Name root VG Name debian7-x64 LV UUID EU6mg0-XTXC-ci3D-bQJi-7XN6-r8Hp-SYxcj0 LV Write Access read/write LV Creation host, time debian7-x64, 2013-06-25 12:02:49 +0530 LV Status available # open 1 LV Size 7.39 GiB Current LE 1892 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 254:0 --- Logical volume --- LV Path /dev/debian7-x64/swap_1 LV Name swap_1 VG Name debian7-x64 LV UUID xDNtoz-tJUq-M5D6-GGCN-gzcD-fwUv-fYYDR1 LV Write Access read/write LV Creation host, time debian7-x64, 2013-06-25 12:02:49 +0530 LV Status available # open 2 LV Size 376.00 MiB Current LE 94 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 254:1 root@debian7-x64:~# pvdisplay --- Physical volume --- PV Name /dev/sda5 VG Name debian7-x64 PV Size 7.76 GiB / not usable 2.00 MiB Allocatable yes (but full) PE Size 4.00 MiB Total PE 1986 Free PE 0 Allocated PE 1986 PV UUID SehkzH-Gq8Y-jI2f-27Tb-uv1Z-tR1R-5OnTxR root@debian7-x64:~# sfdisk -s /dev/sda: 15728640 /dev/mapper/debian7--x64-root: 7749632 /dev/mapper/debian7--x64-swap_1: 385024 total: 23863296 blocks Help me to extend this partition. No problem in rebooting. I dont have any live CD. Environment : debian 7, with lvm, on vsphere, ext4 partition. Can provide more details when needed.

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  • Extending partition on linux gparted but not more space in the vm

    - by Asken
    I have a vm test installation of a linux running a build server. Unfortunately I just pressed ok when adding the disk and ended up with an 8gb drive to play with. Well into the test the builds are consuming more and more space, of course. The vm drive was resized to 21gb and using gparted I expanded the drive partitions and that all worked fine but when I go back into the console and do df there's still only 8gb available. How can I claim the other 13gb I added? fdisk -l Disk /dev/sda: 21.0 GB, 20971520000 bytes 255 heads, 63 sectors/track, 2549 cylinders, total 40960000 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x0006d284 Device Boot Start End Blocks Id System /dev/sda1 * 2048 499711 248832 83 Linux /dev/sda2 501758 40959999 20229121 5 Extended /dev/sda5 501760 40959999 20229120 8e Linux LVM vgdisplay --- Volume group --- VG Name ct System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 4 VG Access read/write VG Status resizable MAX LV 0 Cur LV 2 Open LV 2 Max PV 0 Cur PV 1 Act PV 1 VG Size 19.29 GiB PE Size 4.00 MiB Total PE 4938 Alloc PE / Size 1977 / 7.72 GiB Free PE / Size 2961 / 11.57 GiB VG UUID MwiMAz-52e1-iGVf-eL4f-P5lq-FvRA-L73Sl3 lvdisplay --- Logical volume --- LV Name /dev/ct/root VG Name ct LV UUID Rfk9fh-kqdM-q7t5-ml6i-EjE8-nMtU-usBF0m LV Write Access read/write LV Status available # open 1 LV Size 5.73 GiB Current LE 1466 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 252:0 --- Logical volume --- LV Name /dev/ct/swap_1 VG Name ct LV UUID BLFaa6-1f5T-4MM0-5goV-1aur-nzl9-sNLXIs LV Write Access read/write LV Status available # open 2 LV Size 2.00 GiB Current LE 511 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 252:1

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  • vSphere education - What are the downsides of configuring virtual machines with *too* much RAM?

    - by ewwhite
    VMware memory management seems to be a tricky balancing act. With cluster RAM, Resource Pools, VMware's management techniques (TPS, ballooning, host swapping), in-guest RAM utilization, swapping, reservations, shares and limits, there are a lot of variables. I'm in a situation where clients are using dedicated vSphere cluster resources. However, they are configuring the virtual machines as though they were on physical hardware. In turn, this means a standard VM build may have 4 vCPUs and 16GB or more of RAM. I come from the school of starting small (1 vCPU, minimal RAM), checking real-world use and adjusting up as necessary. Some examples from a "problem" cluster. Resource pool summary - Looks almost 4:1 overcommitted. Note the high amount of ballooned RAM. Resource allocation - The Worst Case Allocation column shows that these VMs would have access to less than 50% of their configured RAM under constrained conditions. The real-time memory utilization graph of the top VM in the listing above. 4 vCPU and 64GB RAM allocated. It averages under 9GB use. Summary of the same VM What are the downsides of overcommitting and overconfiguring resources (specifically RAM) in vSphere environments? Assuming that the VMs can run in less RAM, is it fair to say that there's overhead to configuring virtual machines with more RAM than they need? What is the counter-argument to: "if a VM has 16GB of RAM allocated, but only uses 4GB, what's the problem??"? E.g. do customers need to be educated? What specific metric should be used to meter RAM usage. Tracking the peaks of "Active" versus time?

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  • SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

    - by pinaldave
    This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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  • Demantra 7.3.1.3 Controlling MDP_MATRIX Combinations Assigned to Forecasting Tasks Using TargetTaskSize

    - by user702295
    New 7.3.1.3 parameter: TargetTaskSize Old parameter: BranchID  Multiple, deprecated  7.3.1.3 onwards Parameter Location: Parameters > System Parameters > Engine > Proport   Default: 0   Engine Mode: Both   Details: Specifies how many MDP_MATRIX combinations the analytical engine attempts to assign to each forecasting task.  Allocation will be affected by forecsat tree branch size.  TaskTargetSize is automcatically calculated.  It holds the perferred branch size, in number of combinations in the lowest level. This parameter is adjusted to a lower value for smaller schemas, depending on the number of available engines.   - As the forecast is generated the engine goes up the tree using max_fore_level and not top_level -1.  Max_fore_level has     to be less than or equal to top_level -1.  Due to this requirement, combinations falling under the same top level -1     member must be in the same task.  A member of the top level -1 of the forecast tree is known as a branch.  An engine     task is therefore comprised of one or more branches.     - Reveal current task size       go to Engine Administrator --> View --> Branch Information and run the application on your Demantra schema.  This will be deprecated in 7.3.1.3 since there is no longer a means of adjusting the brach size directly.  The focus is now on proper hierarchy / forecast design.     - Control of tasks       The number of tasks created is the lowest of number of branches, as defined by top level -1 members in forecast       tree, and engine sessions and the value of TargetTaskSize.  You are used to using the branch multiplier in this       calculation.  As of 7.3.1.3, the branch ID multiple is deprecated.     - Discovery of current branch size       To resolve this you must review the 2nd highest level in the forecast tree (below highest/highest) as this is the       level which determines the size of the branches.  If a few resulting tasks are too large it is recommended that       the forecast tree level driving branches be revised or at times completely removed from the forecast tree.     - Control of foreacast tree branch size         - Run the following sql to determine how even the branches are being split by the engine:             select count(*),branch_id from mdp_matrix where prediction_status = 1 and do_fore = 1 group by branch_id;             This will give you an understanding if some of the individual branches have an unusually large number of           rows and thus might indicate that the engine is not efficiently dividing up the parallel tasks.         - Based on the results of this sql, we may want to adjust the branch id multiplier and/or the number of engines           (both of these settings are found in the Engine Administrator)           select count(*), level_id from mdp_matrix where prediction_status = 1 and do_fore = 1 group by level_id;           This will give us an understanding at which level of the Forecast tree where the forecast is being generated.            Having a majority of combinations higher on the forecast tree might indicate either a poorly designed forecast           tree and/or engine parameters that are too strict           Based on the results of this we would adjust the Forecast Tree to see if choosing a different hierarchy might           produce a forecast, with more combinations, at a lower level.           For example:             - Review the 2nd highest level in the forecast tree, below highest/highest, as this is the level which               determines the size of the branches.             - If a few resulting tasks are too large it is recommended that the forecast tree level driving branches               be revised or at times completely removed from the forecast tree.               - For example, if the highest level of the forecast tree is set to Brand/All Locations.             - You have 10 brands but 2 of the brands account for 67% and 29% of all combinations.             - There is a distinct possibility that the tasks resulting from these 2 branches will be too large for               a single engine to process.  Some possible solutions could be to remove the Brand level and instead               use a different product grouping which has a more even distribution, possibly Product Group.               - It is also possible to add a location dimension to this forecast tree level, for example Customer.                This will also reduce forecast tree branch size and will deliver a balanced task allocation.             - A correctly configured Forecast Tree is something that is done by the Implementation team and is               not the responsibility of Oracle Support.  Allocation will be affected by forecast tree branch size.  When TargetTaskSize is set to 0, the default value, the system automatically calculates a value for 'TargetTaskSize' depending on the number of engines.   - QUESTION:  Does this mean that if TargetTaskSize is 1, we use tree branch size to allocate branches to tasks instead                of automatically calculating the size?     ANSWER: DEV Strongly recommends that the setting of TargetTaskSize remain at the DEFAULT of ZERO (0).   - How to control the number of engines?     Determine how many CPUs are on the machine(s) that is (are) running the engine.  As mentioned earlier, the general     rule is that you should designate 2 engines per each CPU that is available.  So for example, if you are running the     engine on a machine that has 4 CPU then you can have up to 8 engines designated in the Engine Administrator.  In this     type of architecture then instead of having one 'localhost' in your Engine Settings Screen, you would have 'localhost'     repeated eight times in this field.     Where do I set the number of engines?                 To add multiples computers where engine will run, please do a back-up of Settings.xml file under         Analytical Engines\bin\ folder, then edit it and add there the selected machines.                 Example, this will allow 3 engines to start:         - <Entry>           <Key argument="ComputerNames" />           <Value type="string" argument="localhost,localhost,localhost" />           </Entry Otherwise, if there are no additional engines defined, the calculated value of 'TargetTaskSize' is used. (Oracle does not recommend changing the default value.) The TargetTaskSize holds the engines prefered branch size, in number of level 1 combinations.   - Level 1 combinations, known as group size The engine manager will use this parameter to attempt creating branches with similar size.   * The engine manager will not create engines that do not have a branch. The engine divider algorithm uses the value of 'TargetTaskSize' as a system-preferred branch size to create branches that are more equal in size which improves engine performance.  The engine divider will try to add as many tasks as possible to an existing branch, up to the limit of 'TargetTaskSize' level 1 combinations, before adding new branches. Coming up next: - The engine divider - Group size - Level 1 combinations - MAX_FORE_LEVEL - Engine Parameters  

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  • LVM / Device Mapper maps wrong device

    - by DaDaDom
    Hi, I run a LVM setup on a raid1 created by mdadm. md2 is based on sda6 (major:minor 8:6) and sdb6 (8:22). md2 is partition 9:2. The VG on top of md2 has 4 LVs, var, home, usr, tmp. First the problem: While booting it seems as if the device mapper takes the wrong partition for the mapping! Immediately after boot the information is like ~# dmsetup table systemlvm-home: 0 4194304 linear 8:22 384 systemlvm-home: 4194304 16777216 linear 8:22 69206400 systemlvm-home: 20971520 8388608 linear 8:22 119538048 systemlvm-home: 29360128 6291456 linear 8:22 243270016 systemlvm-tmp: 0 2097152 linear 8:22 41943424 systemlvm-usr: 0 10485760 linear 8:22 20971904 systemlvm-var: 0 10485760 linear 8:22 10486144 systemlvm-var: 10485760 6291456 linear 8:22 4194688 systemlvm-var: 16777216 4194304 linear 8:22 44040576 systemlvm-var: 20971520 10485760 linear 8:22 31457664 systemlvm-var: 31457280 20971520 linear 8:22 48234880 systemlvm-var: 52428800 33554432 linear 8:22 85983616 systemlvm-var: 85983232 115343360 linear 8:22 127926656 ~# cat /proc/mdstat Personalities : [raid1] md2 : active (auto-read-only) raid1 sda6[0] 151798080 blocks [2/1] [U_] md0 : active raid1 sda1[0] sdb1[1] 96256 blocks [2/2] [UU] md1 : active raid1 sda2[0] sdb2[1] 2931776 blocks [2/2] [UU] I have to manually "lvchange -an" all LVs, add /dev/sdb6 back to the raid and reactivate the LVs, then all is fine. But it prevents me from automounting the partitions and obviously leads to a bunch of other problems. If everything works fine, the information is like ~$ cat /proc/mdstat Personalities : [raid1] md2 : active raid1 sdb6[1] sda6[0] 151798080 blocks [2/2] [UU] ... ~# dmsetup table systemlvm-home: 0 4194304 linear 9:2 384 systemlvm-home: 4194304 16777216 linear 9:2 69206400 systemlvm-home: 20971520 8388608 linear 9:2 119538048 systemlvm-home: 29360128 6291456 linear 9:2 243270016 systemlvm-tmp: 0 2097152 linear 9:2 41943424 systemlvm-usr: 0 10485760 linear 9:2 20971904 systemlvm-var: 0 10485760 linear 9:2 10486144 systemlvm-var: 10485760 6291456 linear 9:2 4194688 systemlvm-var: 16777216 4194304 linear 9:2 44040576 systemlvm-var: 20971520 10485760 linear 9:2 31457664 systemlvm-var: 31457280 20971520 linear 9:2 48234880 systemlvm-var: 52428800 33554432 linear 9:2 85983616 systemlvm-var: 85983232 115343360 linear 9:2 127926656 I think that LVM for some reason just "takes" /dev/sdb6 which is then missing in the raid. I tried almost all options in the lvm.conf but none seems to work. Below is some more information, like config files. Does anyone have any idea about what is going on here and how to prevent that? If you need any additional information, please let me know Thanks in advance! Dominik The information (off a "repaired" system): ~# cat /etc/debian_version 5.0.4 ~# uname -a Linux kermit 2.6.26-2-686 #1 SMP Wed Feb 10 08:59:21 UTC 2010 i686 GNU/Linux ~# lvm version LVM version: 2.02.39 (2008-06-27) Library version: 1.02.27 (2008-06-25) Driver version: 4.13.0 ~# cat /etc/mdadm/mdadm.conf DEVICE partitions ARRAY /dev/md1 level=raid1 num-devices=2 metadata=00.90 UUID=11e9dc6c:1da99f3f:b3088ca6:c6fe60e9 ARRAY /dev/md0 level=raid1 num-devices=2 metadata=00.90 UUID=92ed1e4b:897361d3:070682b3:3baa4fa1 ARRAY /dev/md2 level=raid1 num-devices=2 metadata=00.90 UUID=601d4642:39dc80d7:96e8bbac:649924ba ~# mount /dev/md1 on / type ext3 (rw,errors=remount-ro) tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755) proc on /proc type proc (rw,noexec,nosuid,nodev) sysfs on /sys type sysfs (rw,noexec,nosuid,nodev) procbususb on /proc/bus/usb type usbfs (rw) udev on /dev type tmpfs (rw,mode=0755) tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev) devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620) /dev/md0 on /boot type ext3 (rw) /dev/mapper/systemlvm-usr on /usr type reiserfs (rw) /dev/mapper/systemlvm-tmp on /tmp type reiserfs (rw) /dev/mapper/systemlvm-home on /home type reiserfs (rw) /dev/mapper/systemlvm-var on /var type reiserfs (rw) ~# grep -v ^$ /etc/lvm/lvm.conf | grep -v "#" devices { dir = "/dev" scan = [ "/dev" ] preferred_names = [ ] filter = [ "a|/dev/md.*|", "r/.*/" ] cache_dir = "/etc/lvm/cache" cache_file_prefix = "" write_cache_state = 1 sysfs_scan = 1 md_component_detection = 1 ignore_suspended_devices = 0 } log { verbose = 0 syslog = 1 overwrite = 0 level = 0 indent = 1 command_names = 0 prefix = " " } backup { backup = 1 backup_dir = "/etc/lvm/backup" archive = 1 archive_dir = "/etc/lvm/archive" retain_min = 10 retain_days = 30 } shell { history_size = 100 } global { umask = 077 test = 0 units = "h" activation = 1 proc = "/proc" locking_type = 1 fallback_to_clustered_locking = 1 fallback_to_local_locking = 1 locking_dir = "/lib/init/rw" } activation { missing_stripe_filler = "/dev/ioerror" reserved_stack = 256 reserved_memory = 8192 process_priority = -18 mirror_region_size = 512 readahead = "auto" mirror_log_fault_policy = "allocate" mirror_device_fault_policy = "remove" } :~# vgscan -vvv Processing: vgscan -vvv O_DIRECT will be used Setting global/locking_type to 1 File-based locking selected. Setting global/locking_dir to /lib/init/rw Locking /lib/init/rw/P_global WB Wiping cache of LVM-capable devices /dev/block/1:0: Added to device cache /dev/block/1:1: Added to device cache /dev/block/1:10: Added to device cache /dev/block/1:11: Added to device cache /dev/block/1:12: Added to device cache /dev/block/1:13: Added to device cache /dev/block/1:14: Added to device cache /dev/block/1:15: Added to device cache /dev/block/1:2: Added to device cache /dev/block/1:3: Added to device cache /dev/block/1:4: Added to device cache /dev/block/1:5: Added to device cache /dev/block/1:6: Added to device cache /dev/block/1:7: Added to device cache /dev/block/1:8: Added to device cache /dev/block/1:9: Added to device cache /dev/block/253:0: Added to device cache /dev/block/253:1: Added to device cache /dev/block/253:2: Added to device cache /dev/block/253:3: Added to device cache /dev/block/8:0: Added to device cache /dev/block/8:1: Added to device cache /dev/block/8:16: Added to device cache /dev/block/8:17: Added to device cache /dev/block/8:18: Added to device cache /dev/block/8:19: Added to device cache /dev/block/8:2: Added to device cache /dev/block/8:21: Added to device cache /dev/block/8:22: Added to device cache /dev/block/8:3: Added to device cache /dev/block/8:5: Added to device cache /dev/block/8:6: Added to device cache /dev/block/9:0: Already in device cache /dev/block/9:1: Already in device cache /dev/block/9:2: Already in device cache /dev/bsg/0:0:0:0: Not a block device /dev/bsg/1:0:0:0: Not a block device /dev/bus/usb/001/001: Not a block device [... many more "not a block device"] /dev/core: Not a block device /dev/cpu_dma_latency: Not a block device /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895: Aliased to /dev/block/8:16 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part1: Aliased to /dev/block/8:17 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part2: Aliased to /dev/block/8:18 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part3: Aliased to /dev/block/8:19 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part5: Aliased to /dev/block/8:21 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L507895-part6: Aliased to /dev/block/8:22 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800: Aliased to /dev/block/8:0 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part1: Aliased to /dev/block/8:1 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part2: Aliased to /dev/block/8:2 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part3: Aliased to /dev/block/8:3 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part5: Aliased to /dev/block/8:5 in device cache /dev/disk/by-id/ata-SAMSUNG_HD160JJ_S08HJ10L526800-part6: Aliased to /dev/block/8:6 in device cache /dev/disk/by-id/dm-name-systemlvm-home: Aliased to /dev/block/253:2 in device cache /dev/disk/by-id/dm-name-systemlvm-tmp: Aliased to /dev/block/253:3 in device cache /dev/disk/by-id/dm-name-systemlvm-usr: Aliased to /dev/block/253:1 in device cache /dev/disk/by-id/dm-name-systemlvm-var: Aliased to /dev/block/253:0 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr25N7CRZpUMzR18NfS6zeSeAVnVT98LuU: Aliased to /dev/block/253:0 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr3TpFXtLjYGEwn79IdXsSCZPl8AxmqbmQ: Aliased to /dev/block/253:1 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvrc5MJ4KolevMjt85PPBrQuRTkXbx6NvTi: Aliased to /dev/block/253:3 in device cache /dev/disk/by-id/dm-uuid-LVM-rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvrYXrfdg5OSYDVkNeiQeQksgCI849Z2hx8: Aliased to /dev/block/253:2 in device cache /dev/disk/by-id/md-uuid-11e9dc6c:1da99f3f:b3088ca6:c6fe60e9: Already in device cache /dev/disk/by-id/md-uuid-601d4642:39dc80d7:96e8bbac:649924ba: Already in device cache /dev/disk/by-id/md-uuid-92ed1e4b:897361d3:070682b3:3baa4fa1: Already in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895: Aliased to /dev/block/8:16 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part1: Aliased to /dev/block/8:17 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part2: Aliased to /dev/block/8:18 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part3: Aliased to /dev/block/8:19 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part5: Aliased to /dev/block/8:21 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L507895-part6: Aliased to /dev/block/8:22 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800: Aliased to /dev/block/8:0 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part1: Aliased to /dev/block/8:1 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part2: Aliased to /dev/block/8:2 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part3: Aliased to /dev/block/8:3 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part5: Aliased to /dev/block/8:5 in device cache /dev/disk/by-id/scsi-SATA_SAMSUNG_HD160JJS08HJ10L526800-part6: Aliased to /dev/block/8:6 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0: Aliased to /dev/block/8:0 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part1: Aliased to /dev/block/8:1 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part2: Aliased to /dev/block/8:2 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part3: Aliased to /dev/block/8:3 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part5: Aliased to /dev/block/8:5 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-0:0:0:0-part6: Aliased to /dev/block/8:6 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0: Aliased to /dev/block/8:16 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part1: Aliased to /dev/block/8:17 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part2: Aliased to /dev/block/8:18 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part3: Aliased to /dev/block/8:19 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part5: Aliased to /dev/block/8:21 in device cache /dev/disk/by-path/pci-0000:00:0f.0-scsi-1:0:0:0-part6: Aliased to /dev/block/8:22 in device cache /dev/disk/by-uuid/13c1262b-e06f-40ce-b088-ce410640a6dc: Aliased to /dev/block/253:3 in device cache /dev/disk/by-uuid/379f57b0-2e03-414c-808a-f76160617336: Aliased to /dev/block/253:2 in device cache /dev/disk/by-uuid/4fb2d6d3-bd51-48d3-95ee-8e404faf243d: Already in device cache /dev/disk/by-uuid/5c6728ec-82c1-49c0-93c5-f6dbd5c0d659: Aliased to /dev/block/8:5 in device cache /dev/disk/by-uuid/a13cdfcd-2191-4185-a727-ffefaf7a382e: Aliased to /dev/block/253:1 in device cache /dev/disk/by-uuid/e0d5893d-ff88-412f-b753-9e3e9af3242d: Aliased to /dev/block/8:21 in device cache /dev/disk/by-uuid/e79c9da6-8533-4e55-93ec-208876671edc: Aliased to /dev/block/253:0 in device cache /dev/disk/by-uuid/f3f176f5-12f7-4af8-952a-c6ac43a6e332: Already in device cache /dev/dm-0: Aliased to /dev/block/253:0 in device cache (preferred name) /dev/dm-1: Aliased to /dev/block/253:1 in device cache (preferred name) /dev/dm-2: Aliased to /dev/block/253:2 in device cache (preferred name) /dev/dm-3: Aliased to /dev/block/253:3 in device cache (preferred name) /dev/fd: Symbolic link to directory /dev/full: Not a block device /dev/hpet: Not a block device /dev/initctl: Not a block device /dev/input/by-path/platform-i8042-serio-0-event-kbd: Not a block device /dev/input/event0: Not a block device /dev/input/mice: Not a block device /dev/kmem: Not a block device /dev/kmsg: Not a block device /dev/log: Not a block device /dev/loop/0: Added to device cache /dev/MAKEDEV: Not a block device /dev/mapper/control: Not a block device /dev/mapper/systemlvm-home: Aliased to /dev/dm-2 in device cache /dev/mapper/systemlvm-tmp: Aliased to /dev/dm-3 in device cache /dev/mapper/systemlvm-usr: Aliased to /dev/dm-1 in device cache /dev/mapper/systemlvm-var: Aliased to /dev/dm-0 in device cache /dev/md0: Already in device cache /dev/md1: Already in device cache /dev/md2: Already in device cache /dev/mem: Not a block device /dev/net/tun: Not a block device /dev/network_latency: Not a block device /dev/network_throughput: Not a block device /dev/null: Not a block device /dev/port: Not a block device /dev/ppp: Not a block device /dev/psaux: Not a block device /dev/ptmx: Not a block device /dev/pts/0: Not a block device /dev/ram0: Aliased to /dev/block/1:0 in device cache (preferred name) /dev/ram1: Aliased to /dev/block/1:1 in device cache (preferred name) /dev/ram10: Aliased to /dev/block/1:10 in device cache (preferred name) /dev/ram11: Aliased to /dev/block/1:11 in device cache (preferred name) /dev/ram12: Aliased to /dev/block/1:12 in device cache (preferred name) /dev/ram13: Aliased to /dev/block/1:13 in device cache (preferred name) /dev/ram14: Aliased to /dev/block/1:14 in device cache (preferred name) /dev/ram15: Aliased to /dev/block/1:15 in device cache (preferred name) /dev/ram2: Aliased to /dev/block/1:2 in device cache (preferred name) /dev/ram3: Aliased to /dev/block/1:3 in device cache (preferred name) /dev/ram4: Aliased to /dev/block/1:4 in device cache (preferred name) /dev/ram5: Aliased to /dev/block/1:5 in device cache (preferred name) /dev/ram6: Aliased to /dev/block/1:6 in device cache (preferred name) /dev/ram7: Aliased to /dev/block/1:7 in device cache (preferred name) /dev/ram8: Aliased to /dev/block/1:8 in device cache (preferred name) /dev/ram9: Aliased to /dev/block/1:9 in device cache (preferred name) /dev/random: Not a block device /dev/root: Already in device cache /dev/rtc: Not a block device /dev/rtc0: Not a block device /dev/sda: Aliased to /dev/block/8:0 in device cache (preferred name) /dev/sda1: Aliased to /dev/block/8:1 in device cache (preferred name) /dev/sda2: Aliased to /dev/block/8:2 in device cache (preferred name) /dev/sda3: Aliased to /dev/block/8:3 in device cache (preferred name) /dev/sda5: Aliased to /dev/block/8:5 in device cache (preferred name) /dev/sda6: Aliased to /dev/block/8:6 in device cache (preferred name) /dev/sdb: Aliased to /dev/block/8:16 in device cache (preferred name) /dev/sdb1: Aliased to /dev/block/8:17 in device cache (preferred name) /dev/sdb2: Aliased to /dev/block/8:18 in device cache (preferred name) /dev/sdb3: Aliased to /dev/block/8:19 in device cache (preferred name) /dev/sdb5: Aliased to /dev/block/8:21 in device cache (preferred name) /dev/sdb6: Aliased to /dev/block/8:22 in device cache (preferred name) /dev/shm/network/ifstate: Not a block device /dev/snapshot: Not a block device /dev/sndstat: stat failed: Datei oder Verzeichnis nicht gefunden /dev/stderr: Not a block device /dev/stdin: Not a block device /dev/stdout: Not a block device /dev/systemlvm/home: Aliased to /dev/dm-2 in device cache /dev/systemlvm/tmp: Aliased to /dev/dm-3 in device cache /dev/systemlvm/usr: Aliased to /dev/dm-1 in device cache /dev/systemlvm/var: Aliased to /dev/dm-0 in device cache /dev/tty: Not a block device /dev/tty0: Not a block device [... many more "not a block device"] /dev/vcsa6: Not a block device /dev/xconsole: Not a block device /dev/zero: Not a block device Wiping internal VG cache lvmcache: initialised VG #orphans_lvm1 lvmcache: initialised VG #orphans_pool lvmcache: initialised VG #orphans_lvm2 Reading all physical volumes. This may take a while... Finding all volume groups /dev/ram0: Skipping (regex) /dev/loop/0: Skipping (sysfs) /dev/sda: Skipping (regex) Opened /dev/md0 RO /dev/md0: size is 192512 sectors Closed /dev/md0 /dev/md0: size is 192512 sectors Opened /dev/md0 RW O_DIRECT /dev/md0: block size is 1024 bytes Closed /dev/md0 Using /dev/md0 Opened /dev/md0 RW O_DIRECT /dev/md0: block size is 1024 bytes /dev/md0: No label detected Closed /dev/md0 /dev/dm-0: Skipping (regex) /dev/ram1: Skipping (regex) /dev/sda1: Skipping (regex) Opened /dev/md1 RO /dev/md1: size is 5863552 sectors Closed /dev/md1 /dev/md1: size is 5863552 sectors Opened /dev/md1 RW O_DIRECT /dev/md1: block size is 4096 bytes Closed /dev/md1 Using /dev/md1 Opened /dev/md1 RW O_DIRECT /dev/md1: block size is 4096 bytes /dev/md1: No label detected Closed /dev/md1 /dev/dm-1: Skipping (regex) /dev/ram2: Skipping (regex) /dev/sda2: Skipping (regex) Opened /dev/md2 RO /dev/md2: size is 303596160 sectors Closed /dev/md2 /dev/md2: size is 303596160 sectors Opened /dev/md2 RW O_DIRECT /dev/md2: block size is 4096 bytes Closed /dev/md2 Using /dev/md2 Opened /dev/md2 RW O_DIRECT /dev/md2: block size is 4096 bytes /dev/md2: lvm2 label detected lvmcache: /dev/md2: now in VG #orphans_lvm2 (#orphans_lvm2) /dev/md2: Found metadata at 39936 size 2632 (in area at 2048 size 194560) for systemlvm (rL8Oq2-dA7o-eRYe-u1or-JA7U-fnb1-kjOyvr) lvmcache: /dev/md2: now in VG systemlvm with 1 mdas lvmcache: /dev/md2: setting systemlvm VGID to rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr lvmcache: /dev/md2: VG systemlvm: Set creation host to rescue. Closed /dev/md2 /dev/dm-2: Skipping (regex) /dev/ram3: Skipping (regex) /dev/sda3: Skipping (regex) /dev/dm-3: Skipping (regex) /dev/ram4: Skipping (regex) /dev/ram5: Skipping (regex) /dev/sda5: Skipping (regex) /dev/ram6: Skipping (regex) /dev/sda6: Skipping (regex) /dev/ram7: Skipping (regex) /dev/ram8: Skipping (regex) /dev/ram9: Skipping (regex) /dev/ram10: Skipping (regex) /dev/ram11: Skipping (regex) /dev/ram12: Skipping (regex) /dev/ram13: Skipping (regex) /dev/ram14: Skipping (regex) /dev/ram15: Skipping (regex) /dev/sdb: Skipping (regex) /dev/sdb1: Skipping (regex) /dev/sdb2: Skipping (regex) /dev/sdb3: Skipping (regex) /dev/sdb5: Skipping (regex) /dev/sdb6: Skipping (regex) Locking /lib/init/rw/V_systemlvm RB Finding volume group "systemlvm" Opened /dev/md2 RW O_DIRECT /dev/md2: block size is 4096 bytes /dev/md2: lvm2 label detected lvmcache: /dev/md2: now in VG #orphans_lvm2 (#orphans_lvm2) with 1 mdas /dev/md2: Found metadata at 39936 size 2632 (in area at 2048 size 194560) for systemlvm (rL8Oq2-dA7o-eRYe-u1or-JA7U-fnb1-kjOyvr) lvmcache: /dev/md2: now in VG systemlvm with 1 mdas lvmcache: /dev/md2: setting systemlvm VGID to rL8Oq2dA7oeRYeu1orJA7Ufnb1kjOyvr lvmcache: /dev/md2: VG systemlvm: Set creation host to rescue. Using cached label for /dev/md2 Read systemlvm metadata (19) from /dev/md2 at 39936 size 2632 /dev/md2 0: 0 16: home(0:0) /dev/md2 1: 16 24: var(40:0) /dev/md2 2: 40 40: var(0:0) /dev/md2 3: 80 40: usr(0:0) /dev/md2 4: 120 40: var(80:0) /dev/md2 5: 160 8: tmp(0:0) /dev/md2 6: 168 16: var(64:0) /dev/md2 7: 184 80: var(120:0) /dev/md2 8: 264 64: home(16:0) /dev/md2 9: 328 128: var(200:0) /dev/md2 10: 456 32: home(80:0) /dev/md2 11: 488 440: var(328:0) /dev/md2 12: 928 24: home(112:0) /dev/md2 13: 952 206: NULL(0:0) Found volume group "systemlvm" using metadata type lvm2 Read volume group systemlvm from /etc/lvm/backup/systemlvm Unlocking /lib/init/rw/V_systemlvm Closed /dev/md2 Unlocking /lib/init/rw/P_global ~# vgdisplay --- Volume group --- VG Name systemlvm System ID Format lvm2 Metadata Areas 1 Metadata Sequence No 19 VG Access read/write VG Status resizable MAX LV 0 Cur LV 4 Open LV 4 Max PV 0 Cur PV 1 Act PV 1 VG Size 144,75 GB PE Size 128,00 MB Total PE 1158 Alloc PE / Size 952 / 119,00 GB Free PE / Size 206 / 25,75 GB VG UUID rL8Oq2-dA7o-eRYe-u1or-JA7U-fnb1-kjOyvr ~# pvdisplay --- Physical volume --- PV Name /dev/md2 VG Name systemlvm PV Size 144,77 GB / not usable 16,31 MB Allocatable yes PE Size (KByte) 131072 Total PE 1158 Free PE 206 Allocated PE 952 PV UUID ZSAzP5-iBvr-L7jy-wB8T-AiWz-0g3m-HLK66Y :~# lvdisplay --- Logical volume --- LV Name /dev/systemlvm/home VG Name systemlvm LV UUID YXrfdg-5OSY-DVkN-eiQe-Qksg-CI84-9Z2hx8 LV Write Access read/write LV Status available # open 2 LV Size 17,00 GB Current LE 136 Segments 4 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:2 --- Logical volume --- LV Name /dev/systemlvm/var VG Name systemlvm LV UUID 25N7CR-ZpUM-zR18-NfS6-zeSe-AVnV-T98LuU LV Write Access read/write LV Status available # open 2 LV Size 96,00 GB Current LE 768 Segments 7 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:0 --- Logical volume --- LV Name /dev/systemlvm/usr VG Name systemlvm LV UUID 3TpFXt-LjYG-Ewn7-9IdX-sSCZ-Pl8A-xmqbmQ LV Write Access read/write LV Status available # open 2 LV Size 5,00 GB Current LE 40 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:1 --- Logical volume --- LV Name /dev/systemlvm/tmp VG Name systemlvm LV UUID c5MJ4K-olev-Mjt8-5PPB-rQuR-TkXb-x6NvTi LV Write Access read/write LV Status available # open 2 LV Size 1,00 GB Current LE 8 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 253:3

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  • concurrency::accelerator_view

    - by Daniel Moth
    Overview We saw previously that accelerator represents a target for our C++ AMP computation or memory allocation and that there is a notion of a default accelerator. We ended that post by introducing how one can obtain accelerator_view objects from an accelerator object through the accelerator class's default_view property and the create_view method. The accelerator_view objects can be thought of as handles to an accelerator. You can also construct an accelerator_view given another accelerator_view (through the copy constructor or the assignment operator overload). Speaking of operator overloading, you can also compare (for equality and inequality) two accelerator_view objects between them to determine if they refer to the same underlying accelerator. We'll see later that when we use concurrency::array objects, the allocation of data takes place on an accelerator at array construction time, so there is a constructor overload that accepts an accelerator_view object. We'll also see later that a new concurrency::parallel_for_each function overload can take an accelerator_view object, so it knows on what target to execute the computation (represented by a lambda that the parallel_for_each also accepts). Beyond normal usage, accelerator_view is a quality of service concept that offers isolation to multiple "consumers" of an accelerator. If in your code you are accessing the accelerator from multiple threads (or, in general, from different parts of your app), then you'll want to create separate accelerator_view objects for each thread. flush, wait, and queuing_mode When you create an accelerator_view via the create_view method of the accelerator, you pass in an option of immediate or deferred, which are the two members of the queuing_mode enum. At any point you can access this value from the queuing_mode property of the accelerator_view. When the queuing_mode value is immediate (which is the default), any commands sent to the device such as kernel invocations and data transfers (e.g. parallel_for_each and copy, as we'll see in future posts), will get submitted as soon as the runtime sees fit (that is the definition of immediate). When the value of queuing_mode is deferred, the commands will be batched up. To send all buffered commands to the device for execution, there is a non-blocking flush method that you can call. If you wish to block until all the commands have been sent, there is a wait method you can call. Deferring is a more advanced scenario aimed at performance gains when you are submitting many device commands and you want to avoid the tiny overhead of flushing/submitting each command separately. Querying information Just like accelerator, accelerator_view exposes the is_debug and version properties. In fact, you can always access the accelerator object from the accelerator property on the accelerator_view class to access the accelerator interface we looked at previously. Interop with D3D (aka DX) In a later post I'll show an example of an app that uses C++ AMP to compute data that is used in pixel shaders. In those scenarios, you can benefit by integrating C++ AMP into your graphics pipeline and one of the building blocks for that is being able to use the same device context from both the compute kernel and the other shaders. You can do that by going from accelerator_view to device context (and vice versa), through part of our interop API in amp.h: *get_device, create_accelerator_view. More on those in a later post. Comments about this post by Daniel Moth welcome at the original blog.

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  • ORA-4031 Troubleshooting

    - by [email protected]
      QUICKLINK: Note 396940.1 Troubleshooting and Diagnosing ORA-4031 Error Note 1087773.1 : ORA-4031 Diagnostics Tools [Video]   Have you observed an ORA-04031 error reported in your alert log? An ORA-4031 error is raised when memory is unavailable for use or reuse in the System Global Area (SGA).  The error message will indicate the memory pool getting errors and high level information about what kind of allocation failed and how much memory was unavailable.  The challenge with ORA-4031 analysis is that the error and associated trace is for a "victim" of the problem.   The failing code ran into the memory limitation, but in almost all cases it was not part of the root problem.    Looking for the best way to diagnose? When an ORA-4031 error occurs, a trace file is raised and noted in the alert log if the process experiencing the error is a background process.   User processes may experience errors without reports in the alert log or traces generated.   The V$SHARED_POOL_RESERVED view will show reports of misses for memory over the life of the database. Diagnostics scripts are available in Note 430473.1 to help in analysis of the problem.  There is also a training video on using and interpreting the script data Note 1087773.1. 11g DiagnosabilityStarting with Oracle Database 11g Release 1, the Diagnosability infrastructure was introduced which places traces and core files into a location controlled by the DIAGNOSTIC_DEST initialization parameter when an incident, such as an ORA-4031 occurs. For earlier versions, the trace file will be written to either USER_DUMP_DEST (if the error was caught in a user process) or BACKGROUND_DUMP_DEST (if the error was caught in a background process like PMON or SMON). The trace file contains vital information about what led to the error condition.  Note 443529.1 11g Quick Steps to Package and Send Critical Error Diagnostic Information to Support[Video]Oracle Configuration Manager (OCM)Oracle Configuration Manager (OCM) works with My Oracle Support to enable proactive support capability that helps you organize, collect and manage your Oracle configurations.Oracle Configuration Manager Quick Start GuideNote 548815.1: My Oracle Support Configuration Management FAQ Note 250434.1: BULLETIN: Learn More About My Oracle Support Configuration Manager    Common Causes/Solutions The ORA-4031 can occur for many different reasons.  Some possible causes are: SGA components too small for workload Auto-tuning issues Fragmentation due to application design Bug/leaks in memory allocationsFor more on the 4031 and how this affects the SGA, see Note 396940.1 Troubleshooting and Diagnosing ORA-4031 Error Because of the multiple potential causes, it is important to gather enough diagnostics so that an appropriate solution can be identified.  However, most commonly the cause is associated with configuration tuning.   Ensuring that MEMORY_TARGET or SGA_TARGET are large enough to accommodate workload can get around many scenarios.  The default trace associated with the error provides very high level information about the memory problem and the "victim" that ran into the issue.   The data in the default trace is not going to point to the root cause of the problem. When migrating from 9i to 10g and higher, it is necessary to increase the size of the Shared Pool due to changes in the basic design of the shared memory area. Note 270935.1 Shared pool sizing in 10gNOTE: Diagnostics on the errors should be investigated as close to the time of the error(s) as possible.  If you must restart a database, it is not feasible to diagnose the problem until the database has matured and/or started seeing the problems again. Note 801787.1 Common Cause for ORA-4031 in 10gR2, Excess "KGH: NO ACCESS" Memory Allocation ***For reference to the content in this blog, refer to Note.1088239.1 Master Note for Diagnosing ORA-4031 

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  • An Actionable Common Approach to Federal Enterprise Architecture

    - by TedMcLaughlan
    The recent “Common Approach to Federal Enterprise Architecture” (US Executive Office of the President, May 2 2012) is extremely timely and well-organized guidance for the Federal IT investment and deployment community, as useful for Federal Departments and Agencies as it is for their stakeholders and integration partners. The guidance not only helps IT Program Planners and Managers, but also informs and prepares constituents who may be the beneficiaries or otherwise impacted by the investment. The FEA Common Approach extends from and builds on the rapidly-maturing Federal Enterprise Architecture Framework (FEAF) and its associated artifacts and standards, already included to a large degree in the annual Federal Portfolio and Investment Management processes – for example the OMB’s Exhibit 300 (i.e. Business Case justification for IT investments).A very interesting element of this Approach includes the very necessary guidance for actually using an Enterprise Architecture (EA) and/or its collateral – good guidance for any organization charged with maintaining a broad portfolio of IT investments. The associated FEA Reference Models (i.e. the BRM, DRM, TRM, etc.) are very helpful frameworks for organizing, understanding, communicating and standardizing across agencies with respect to vocabularies, architecture patterns and technology standards. Determining when, how and to what level of detail to include these reference models in the typically long-running Federal IT acquisition cycles wasn’t always clear, however, particularly during the first interactions of a Program’s technical and functional leadership with the Mission owners and investment planners. This typically occurs as an agency begins the process of describing its strategy and business case for allocation of new Federal funding, reacting to things like new legislation or policy, real or anticipated mission challenges, or straightforward ROI opportunities (for example the introduction of new technologies that deliver significant cost-savings).The early artifacts (i.e. Resource Allocation Plans, Acquisition Plans, Exhibit 300’s or other Business Case materials, etc.) of the intersection between Mission owners, IT and Program Managers are far easier to understand and discuss, when the overlay of an evolved, actionable Enterprise Architecture (such as the FEA) is applied.  “Actionable” is the key word – too many Public Service entity EA’s (including the FEA) have for too long been used simply as a very highly-abstracted standards reference, duly maintained and nominally-enforced by an Enterprise or System Architect’s office. Refreshing elements of this recent FEA Common Approach include one of the first Federally-documented acknowledgements of the “Solution Architect” (the “Problem-Solving” role). This role collaborates with the Enterprise, System and Business Architecture communities primarily on completing actual “EA Roadmap” documents. These are roadmaps grounded in real cost, technical and functional details that are fully aligned with both contextual expectations (for example the new “Digital Government Strategy” and its required roadmap deliverables - and the rapidly increasing complexities of today’s more portable and transparent IT solutions.  We also expect some very critical synergies to develop in early IT investment cycles between this new breed of “Federal Enterprise Solution Architect” and the first waves of the newly-formal “Federal IT Program Manager” roles operating under more standardized “critical competency” expectations (including EA), likely already to be seriously influencing the quality annual CPIC (Capital Planning and Investment Control) processes.  Our Oracle Enterprise Strategy Team (EST) and associated Oracle Enterprise Architecture (OEA) practices are already engaged in promoting and leveraging the visibility of Enterprise Architecture as a key contributor to early IT investment validation, and we look forward in particular to seeing the real, citizen-centric benefits of this FEA Common Approach in particular surface across the entire Public Service CPIC domain - Federal, State, Local, Tribal and otherwise. Read more Enterprise Architecture blog posts for additional EA insight!

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  • Imagemagick PDF to JPG conversion failing

    - by sbressler
    I'm trying to convert the first page of a PDF to a JPG. I'm pretty sure I got this to work with certain PDFs, but is it really possible that certain PDFs are made incorrectly and cannot be converted? I tried running this first: $ convert 10-03-26.pdf[1] test.jpg And I got the follow: Error: /syntaxerror in readxref Operand stack: Execution stack: %interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 1 3 %oparray_pop 1 3 %oparray_pop --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- Dictionary stack: --dict:1062/1417(ro)(G)-- --dict:0/20(G)-- --dict:73/200(L)-- --dict:73/200(L)-- --dict:97/127(ro)(G)-- --dict:229/230(ro)(G)-- --dict:14/15(L)-- Current allocation mode is local ESP Ghostscript 7.07.1: Unrecoverable error, exit code 1 convert: Postscript delegate failed `10-03-26.pdf'. Running this instead: $ convert -verbose -colorspace rgb '10-03-26.pdf[1]' test.jpg I get the following: Error: /syntaxerror in readxref Operand stack: Execution stack: %interp_exit .runexec2 --nostringval-- --nostringval-- --nostringval-- 2 %stopped_push --nostringval-- --nostringval-- --nostringval-- false 1 %stopped_push 1 3 %oparray_pop 1 3 %oparray_pop --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- --nostringval-- Dictionary stack: --dict:1062/1417(ro)(G)-- --dict:0/20(G)-- --dict:73/200(L)-- --dict:73/200(L)-- --dict:97/127(ro)(G)-- --dict:229/230(ro)(G)-- --dict:14/15(L)-- Current allocation mode is local ESP Ghostscript 7.07.1: Unrecoverable error, exit code 1 "gs" -q -dBATCH -dSAFER -dMaxBitmap=500000000 -dNOPAUSE -dAlignToPixels=0 "-sDEVICE=pnmraw" -dTextAlphaBits=4 -dGraphicsAlphaBits=4 "-g792x1611" "-r72x72" -dFirstPage=2 -dLastPage=2 "-sOutputFile=/tmp/magick-XXU3T44P" "-f/tmp/magick-XXoMKL8Z" "-f/tmp/magic2eec1F"Start of Image Define Huffman Table 0x00 0 1 5 1 1 1 1 1 1 0 0 0 0 0 0 0 Define Huffman Table 0x01 0 3 1 1 1 1 1 1 1 1 1 0 0 0 0 0 Define Huffman Table 0x10 0 2 1 3 3 2 4 3 5 5 4 4 0 0 1 125 Define Huffman Table 0x11 0 2 1 2 4 4 3 4 7 5 4 4 0 1 2 119 End Of Image convert: Postscript delegate failed `10-03-26.pdf'. Why would the conversion fail? Thanks!

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  • priority queue with limited space: looking for a good algorithm

    - by SigTerm
    This is not a homework. I'm using a small "priority queue" (implemented as array at the moment) for storing last N items with smallest value. This is a bit slow - O(N) item insertion time. Current implementation keeps track of largest item in array and discards any items that wouldn't fit into array, but I still would like to reduce number of operations further. looking for a priority queue algorithm that matches following requirements: queue can be implemented as array, which has fixed size and _cannot_ grow. Dynamic memory allocation during any queue operation is strictly forbidden. Anything that doesn't fit into array is discarded, but queue keeps all smallest elements ever encountered. O(log(N)) insertion time (i.e. adding element into queue should take up to O(log(N))). (optional) O(1) access for *largest* item in queue (queue stores *smallest* items, so the largest item will be discarded first and I'll need them to reduce number of operations) Easy to implement/understand. Ideally - something similar to binary search - once you understand it, you remember it forever. Elements need not to be sorted in any way. I just need to keep N smallest value ever encountered. When I'll need them, I'll access all of them at once. So technically it doesn't have to be a queue, I just need N last smallest values to be stored. I initially thought about using binary heaps (they can be easily implemented via arrays), but apparently they don't behave well when array can't grow anymore. Linked lists and arrays will require extra time for moving things around. stl priority queue grows and uses dynamic allocation (I may be wrong about it, though). So, any other ideas?

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  • should variable be released or not? iphone-sdk

    - by psebos
    Hi, In the following piece of code (from a book) data is an NSDictionary *data; defined in the header (no property). In the viewDidLoad of the controller the following occurs: - (void)viewDidLoad { [super viewDidLoad]; NSArray *keys = [NSArray arrayWithObjects:@"home", @"work", nil]; NSArray *homeDVDs = [NSArray arrayWithObjects:@"Thomas the Builder", nil]; NSArray *workDVDs = [NSArray arrayWithObjects:@"Intro to Blender", nil]; NSArray *values = [NSArray arrayWithObjects:homeDVDs, workDVDs, nil]; data = [[NSDictionary alloc] initWithObjects:values forKeys:keys]; } Since I am really new to objective-c can someone explain to me why I do not have to retain the variables keys,homeDVDs,workDVDs and values prior exiting the function? I would expect prior the data allocation something like: [keys retain]; [homeDVDs retain]; [workDVDs retain]; [values retain]; or not? Does InitWithObjects copies (recursively) all objects into a new table? Assuming we did not have the last line (data allocation) should we release all the NSArrays prior exiting the function (or we could safely assumed that all NSArrays will be autoreleased since there is no alloc for each one?) Thanks!!!!

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  • UIViewController memory management

    - by jAmi
    Hi I have a very basic issue of memory management with my UIViewController (or any other object that I create); The problem is that in Instruments my Object allocation graph is always rising even though I am calling release on then assigning them nil. I have 2 UIViewController sub-classes each initializing with a NIB; I add the first ViewController to the main window like [window addSubView:first.view]; Then in my first ViewController nib file I have a Button which loads the second ViewController like : -(IBAction)loadSecondView{ if(second!=nil){ //second is set as an iVar and @property (nonatomic, retain)ViewController2* sceond; [second release]; second=nil; } second=[[ViewController2* second]initWithNibName:@"ViewController2" bundle:nil]; [self.view addSubView:second.view]; } In my (second) ViewController2 i have a button with an action method -(IBAction) removeSecond{ [self.view removeFromSuperView]; } Please let me know if the above scheme works in a managed way for memory...? In Instruments It does not show release of any allocation and keeps the bar status graph keeps on rising.

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  • Design: How to declare a specialized memory handler class

    - by Michael Dorgan
    On an embedded type system, I have created a Small Object Allocator that piggy backs on top of a standard memory allocation system. This allocator is a Boost::simple_segregated_storage< class and it does exactly what I need - O(1) alloc/dealloc time on small objects at the cost of a touch of internal fragmentation. My question is how best to declare it. Right now, it's scope static declared in our mem code module, which is probably fine, but it feels a bit exposed there and is also now linked to that module forever. Normally, I declare it as a monostate or a singleton, but this uses the dynamic memory allocator (where this is located.) Furthermore, our dynamic memory allocator is being initialized and used before static object initialization occurs on our system (as again, the memory manager is pretty much the most fundamental component of an engine.) To get around this catch 22, I added an extra 'if the small memory allocator exists' to see if the small object allocator exists yet. That if that now must be run on every small object allocation. In the scheme of things, this is nearly negligable, but it still bothers me. So the question is, is there a better way to declare this portion of the memory manager that helps decouple it from the memory module and perhaps not costing that extra isinitialized() if statement? If this method uses dynamic memory, please explain how to get around lack of initialization of the small object portion of the manager.

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