onstat -F output

Hi all, I have Informix 7.30.UC2 running on SCO 5.04 and have noticed this on my onstat -F output Fg Writes LRU Writes Chunk Writes 0 0 18463 address flusher state data 874484c4 0 I 0 = 0X0 87448974 1 I 0 = 0X0 87448e24 2 I 0 = 0X0 states: Exit Idle Chunk Lru This is an OLTP system so the LRU writes should be something other than 0 am I correct? Also is noticed that even when a check point occurs my flushers stay idle. Am I missing something here? here is my onconfig file ROOTNAME rootdbs ROOTPATH /dev/rootdbs ROOTOFFSET 0 ROOTSIZE 1774800MIRROR 0 MIRRORPATH MIRROROFFSET 0PHYSDBS rootdbs PHYSFILE 2000 LOGFILES 100 LOGSIZE 5000 MSGPATH /x/inf_logs/online.log CONSOLE /dev/console ALARMPROGRAM /x/usr/informix/etc/log_full.sh SYSALARMPROGRAM /x/usr/informix/etc/evidence.sh TBLSPACE_STATS 1 TAPEDEV /dev/tapedev TAPEBLK 64 TAPESIZE 20000000 LTAPEDEV /dev/ltapedev LTAPEBLK 64 LTAPESIZE 2000000STAGEBLOB SERVERNUM 0 DBSERVERNAME on1_cannon6 DBSERVERALIASES on2_cannon6 NETTYPE ipcshm,1,50,CPU NETTYPE tlitcp,1,50,NET DEADLOCK_TIMEOUT 60 RESIDENT 1 MULTIPROCESSOR 1 NUMCPUVPS 2 SINGLE_CPU_VP 0 NOAGE 1 AFF_SPROC 0 AFF_NPROCS 0 LOCKS 300000 BUFFERS 32000 NUMAIOVPS 2 PHYSBUFF 256 LOGBUFF 32LOGSMAX 1700 CLEANERS 3 SHMBASE 0x82000000 SHMVIRTSIZE 8192 SHMADD 8192 SHMTOTAL 0 CKPTINTVL 300 LRUS 8 LRU_MAX_DIRTY 40 LRU_MIN_DIRTY 20 LTXHWM 45 LTXEHWM 50 TXTIMEOUT 0x12c STACKSIZE 32 OFF_RECVRY_THREADS 10 ON_RECVRY_THREADS 1 DRAUTO 0 DRINTERVAL 30 DRTIMEOUT 30 DRLOSTFOUND /x/usr/informix/etc/dr.lostfoundCDR_LOGBUFFERS 2048 CDR_EVALTHREADS 1,2 CDR_DSLOCKWAIT 5 CDR_QUEUEMEM 4096 BAR_ACT_LOG /x/inf_logs/bar_act.log BAR_MAX_BACKUP 0 BAR_RETRY 1 BAR_NB_XPORT_COUNT 10 BAR_XFER_BUF_SIZE 31 BAR_BSALIB_PATH /usr/lib/ibsad001.soISM_DATA_POOL ISMData ISM_LOG_POOL ISMLogs RA_PAGES 32 RA_THRESHOLD 30 DBSPACETEMP tempdbs DUMPDIR /x/inf_logs DUMPSHMEM 0 DUMPGCORE 0 DUMPCORE 0 DUMPCNT 1 FILLFACTOR 90 USEOSTIME 0 MAX_PDQPRIORITY 50 DS_MAX_QUERIES DS_TOTAL_MEMORY DS_MAX_SCANS 1048576 DATASKIP off OPTCOMPIND 2 ONDBSPACEDOWN 2LBU_PRESERVE 1 OPCACHEMAX 0 HETERO_COMMIT 0 OPT_GOAL 0 DIRECTIVES 1 RESTARTABLE_RESTORE off any help is always appreciated. Joe ------------------------------------------------------------------------- Joseph Cullipher <joseph@cannonexpress.com> Standard Disclaimers Apply -------------------------------------------------------------------------

Joseph Cullipher wrote: > > Hi all, > I have Informix 7.30.UC2 running on SCO 5.04 and have noticed this on > my onstat -F output > > Fg Writes LRU Writes Chunk Writes > 0 0 18463 > > address flusher state data > 874484c4 0 I 0 = 0X0 > 87448974 1 I 0 = 0X0 > 87448e24 2 I 0 = 0X0 > states: Exit Idle Chunk Lru > > This is an OLTP system so the LRU writes should be something other than 0 > am I correct? Also is noticed that even when a check point occurs my flushers > stay idle. Am I missing something here? [SNIP] > LRU_MAX_DIRTY 40 > LRU_MIN_DIRTY 20 Here is your problem. LRU_MAX_DIRTY and LRU_MIN_DIRTY control when buffers are flushed between checkpoints (LRU Writes) you have these set so high that you never flush anything except at checkpoints. Set these to something MUCH lower, even as low as 1 & 0, until you have the ratio of LRU Writes to Chunk Writes that you desire. Personally I like to see at LEAST 90% Chunk Writes with 100% making me smile though I rarely get to smile for this reason anyway. [SNIP] Since your writes are all chunk writes the cleaner threads are writing all of the dirty buffers from each chunk in a few as a single asynch I/O request. You would be har pressed to see them busy during a checkpoint. It seems to me that your PHYSFILE is too small to support 32000 buffers. Check that checkpoints are not occurring before the 300secs you have set because the physical log has filled beyond 75% full. Early checkpoints triggered by the physical log are more of an interrupt to normal processing than timed ones and you risk a physical log overflow which will cause some preimages to become lost putting you at risk in case of a crash. Art S. Kagel

In article <79v8ge$d5j$1@news.xmission.com>, Joseph Cullipher <joseph@cannonexpress.com> wrote: > > Hi all, > I have Informix 7.30.UC2 running on SCO 5.04 and have noticed this on > my onstat -F output > > Fg Writes LRU Writes Chunk Writes > 0 0 18463 > > address flusher state data > 874484c4 0 I 0 = 0X0 > 87448974 1 I 0 = 0X0 > 87448e24 2 I 0 = 0X0 > states: Exit Idle Chunk Lru > > This is an OLTP system so the LRU writes should be something other than 0 > am I correct? Also is noticed that even when a check point occurs my flushers > stay idle. Am I missing something here? > > here is my onconfig file > > Art and Mark are right It might pay off to look at the ratio buffer reads vs. buffer writes and your read- and write cache rate. Maybe you are running heavily read bound and if you do not have many writes (= delete,update,insert) at all you maybe will never see any LRU Writes As to my understanding, onstat -F gives cumulative counts for LRU and chunk writes. How long have these accumulated to read the value shown in your posting (i.e. what was your uptime then??) So maybe let us see the results of this action: Onstat -z (i.e. reset of all counters) After one hour of peak activity do onstat -Fp and post that and I'm sure that I will learnsomething from Art's answer to that posting ... Regards Dick Richard Kofler debis Systemhaus EDVg Vienna / Austria -----------== Posted via Deja News, The Discussion Network ==---------- http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own