Re: Shared Virtual Memory Question/Engine Shutdown

In article <5d8dfb$9au@cssun.mathcs.emory.edu>, Carol Davies <cdavies@csc.com> writes >Our project site recently received a binary executable from a sister >site which updated approximately 5000 stored procedures. The executable >brought down the engine due to shared memory limitations. When looking >at the data (onconfig, memory on machine, etc. as stated below), the >numbers don't exactly seem to add up and I am wondering if someone could >provide further insight, as I a probably missing something important: > >Contents of onconfig as related to shared memory: >SHMBASE 0x30000000 # Shared memory base address >SHMVIRTSIZE 8000 # initial virtual shared memory segment ^^^^^^^ ||||||| ||||||| See Note 1 below. >size (Kbytes) >SHMADD 16384 # Size of new shared memory segments >(Kbytes) >SHMTOTAL 190000 # Total shared memory (Kbytes)> > >Contents of online.log (paraphrased): > >13:14:35 Logical Recovery Started. >13:14:35 dynamically allocated new shared memory segment (size >16777216) 16384K as expected. > >(this is repeated for a total of 7 dynamic allocations). After the 7th >dynamic allocation, there are approximately 25 of the following >messages: > >14:28:46 shmat: [EINVAL][22]: shared memory base address illegal > >14:28:46 using 0xd0000000, needs 0xffffffff > >14:28:46 out of virtual shared memory> The shmat() system call failed with erno = 22 (EINVAL). >which are followed by the engine shutting down with: > >14:28:49 mtshpool.c, line 2549, thread 69, proc id 24814, Condition >Failed ((po >ol != NULL && ptr != NULL)), In (mt_shm_free) > Thread(69, sqlexec, 0, 1). Memory corruption. >14:28:49 PANIC: Attempting to bring system down Online says bye,bye.> >The server memory configuration is as follows: >Virtual paging memory: >>lsps -a >Page Space Physical Volume Volume Group Size %Used Active >Auto Type >paging03 hdisk2 ccmvg 200MB 12 yes >yes lv >paging02 hdisk3 bldvg 200MB 12 yes >yes lv >paging01 hdisk2 ccmvg 200MB 12 yes >yes lv >paging00 hdisk5 pagevg 456MB 5 yes >yes lv >hd6 hdisk4 rootvg 200MB 16 yes >yes lv All ok here - plenty of swap space > >Physcal Memory: > >lsdev -Cc memory >mem0 Available 00-0B 32 MB Memory Card >mem1 Available 00-0D 32 MB Memory Card >mem2 Available 00-0F 32 MB Memory Card >mem3 Available 00-0H 32 MB Memory Card >mem8 Available 00-0C 64 MB Memory Card >mem9 Available 00-0G 64 MB Memory Card > 256Mb phyical memory - not bad. >According to my math, 8000 (initial) + 114688 (16384 X7) = 122688, which Note 1: That is only virtual segments!!! ^^^^^^^ ||||||| SHMTOTAL also includes the RESIDENT and MESSAGE portions of shared memory. Use onstat -g seg to check the size of these. I suspect with 120Mb in virutal portion and 256Mb of physical memory that you have say 190Mb-120Mb = 70Mb in the other portions E.g. 30000*2K buffers (=60Mb) + some for messaging/rest of resident portion. >is less than the onconfig max of 190000, and there is system availble >paging memory, so why the shutdown? The only conceivable reason I can >think of is system virtual paging memory allocated to other system >processes, resources. > >Any help would be appreciated. > >System is AIX 3.2.5 > >OnLine Version 7.12.UC1 >----------------- >Carol Davies >cdavies@csc.com -- David Williams