Professional Web Applications Themes

DB2 max shared memory limitation: 1.1 gigabytes? Where's the doentation? Flawed math? - IBM DB2

I heard DB2 32bit can only safely use up to 1.1 gigabytes of shared memory. I've summed up the ten DB2 memory components that utilize shared memory on the TP1 instance and it adds up to 1,036,091,392 bytes. However, I noticed another DB2 instance GP1 that totals 1,822,097,408. Obviously, 1.8 gb is way beyond the 1.1GB "shared memory limitation". The GP1 seems to be running fine without crashing. I've listed the relevant DB2 configurations of the two example instances TP1 & GP1 below. Is the 32bit DB2 shared memory max limitation officially doented anywhere? Is it really 1.1 GB? Or ...

  1. #1

    Default DB2 max shared memory limitation: 1.1 gigabytes? Where's the doentation? Flawed math?

    I heard DB2 32bit can only safely use up to 1.1 gigabytes of shared
    memory. I've summed up the ten DB2 memory components that utilize
    shared memory on the TP1 instance and it adds up to 1,036,091,392
    bytes. However, I noticed another DB2 instance GP1 that totals
    1,822,097,408. Obviously, 1.8 gb is way beyond the 1.1GB "shared
    memory limitation". The GP1 seems to be running fine without
    crashing. I've listed the relevant DB2 configurations of the two
    example instances TP1 & GP1 below.

    Is the 32bit DB2 shared memory max limitation officially doented
    anywhere? Is it really 1.1 GB? Or is it 1.2 GB? Or is it something
    else entirely?

    (Again, I realize that 64bit DB2 has higher memory limits but both of
    these example instances are 32 bit DB2.)

    Thanks for any insights and help


    instance TP1 (on AIX 4.3.3):
    Backup buffer default size (4KB) (BACKBUFSZ) = 4096
    Restore buffer default size (4KB) (RESTBUFSZ) = 4096
    Sort heap threshold (4KB) (SHEAPTHRES) = 61440
    Database heap (4KB) (DBHEAP) = 47104
    Catalog cache size (4KB) (CATALOGCACHE_SZ) = 4096
    Log buffer size (4KB) (LOGBUFSZ) = 1024
    Utilities heap size (4KB) (UTIL_HEAP_SZ) = 52248
    Buffer pool size (pages) (BUFFPAGE) = 45056
    Max storage for lock list (4KB) (LOCKLIST) = 25600
    Package cache size (4KB) (PCKCACHESZ) = 8192
    252952 total shared memory
    db2tp1 25> bc
    252952*4096
    1036091392

    instance GP1 (on AIX 5):
    Backup buffer default size (4KB) (BACKBUFSZ) = 4096
    Restore buffer default size (4KB) (RESTBUFSZ) = 4096
    Sort heap threshold (4KB) (SHEAPTHRES) = 61440
    Database heap (4KB) (DBHEAP) = 20000
    Catalog cache size (4KB) (CATALOGCACHE_SZ) = 4000
    Log buffer size (4KB) (LOGBUFSZ) = 1024
    Utilities heap size (4KB) (UTIL_HEAP_SZ) = 20480
    Buffer pool size (pages) (BUFFPAGE) = 281520
    Max storage for lock list (4KB) (LOCKLIST) = 40000
    Package cache size (4KB) (PCKCACHESZ) = 8192
    444848 total shared memory
    db2gp1 7> bc
    444848*4096
    1822097408

    J.W. Guest

  2. #2

    Default Re: DB2 max shared memory limitation: 1.1 gigabytes? Where's thedoentation? Flawed math?

    1.75 GB is possible on AIX in 32-bit mode (7 0.25 GB segments). The
    limit is higher on some OS's (Solaris, Windows) and lower on others
    (Linux, HP). If you can't move to 64-bit, you can see the DB2 memory map
    (which confirms your 1.8 GB theory) for 32-bit AIX and Solaris here:

    http://www7b.boulder.ibm.com/dmdd/library/techarticle/adamache/0529_adamache.html

    J.W. wrote:
     

    Blair Guest

  3. #3

    Default Re: DB2 max shared memory limitation: 1.1 gigabytes? Where's the doentation? Flawed math?

    Awesome reply and a perfectly relevant webpage link. Thank you!!!

    On Tue, 23 Sep 2003 16:54:57 -0400, Blair Adamache
    <> wrote:
     [/ref]

    J.W. Guest

Similar Threads

  1. Shared memory and Mac OS X
    By Wes in forum PostgreSQL / PGSQL
    Replies: 5
    Last Post: February 22nd, 04:01 AM
  2. Shared Memory/Shared Buffers
    By Alex Turner in forum PostgreSQL / PGSQL
    Replies: 1
    Last Post: January 28th, 04:09 PM
  3. Memory Usage Limitation, Please Raise it!
    By Jihoon_Kim@adobeforums.com in forum Adobe Photoshop Mac CS, CS2 & CS3
    Replies: 17
    Last Post: February 26th, 12:10 AM
  4. Shared memory in OS X?
    By Mike H. in forum Mac Programming
    Replies: 3
    Last Post: September 30th, 03:46 AM
  5. I think I need a DB with no shared memory
    By dimonex in forum Informix
    Replies: 1
    Last Post: July 3rd, 05:20 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139