Re: Performance Problem with many buffer wait

Which 7.30? Check the Btree percentages using onstat -P|tail. There is a bug in 7.3 that causes the buffers to be eaten up by Btree pages. This may be your problem. Doug Agnew Grace Kan wrote in message <380EA750.7E5DD882@netvigator.com>... >Hi all informix expert, > > I am now using Informix Online 7.30, and I experience a lot of >buffer wait, that is a B flag in first position in onstat -u, which make >my informix database extremely slow. > >c4ad7d24 B--PR-- 50686 hwchung ttyud c22403a8 0 1 1238 >64 > > So why this happen and how to avoid it. And one more question, >why not the onstat -u show lock wait ( L flag in the first position) >rather than buffer wait, as user thread getting a buffer by obtain a >share lock or exclusive lock on that buffer. > > Looking forward to have your reply > >Best Regards, >Grace >ps. attached is onstat -c and onstat -p > >#************************************************************************** > ># ># INFORMIX SOFTWARE, INC. ># ># Title: onconfig.01 ># Description: INFORMIX-OnLine Configuration Parameters ># >#************************************************************************** > ># Root Dbspace Configuration > >ROOTNAME rootdbs # Root dbspace name >ROOTPATH /dev/rootdcs.1 # Path for device containing root>dbspace >ROOTOFFSET 0 # Offset of root dbspace into device >(Kbytes) >ROOTSIZE 204800 # Size of root dbspace (Kbytes)> ># Disk Mirroring Configuration Parameters > >MIRROR 0 # Mirroring flag (Yes = 1, No = 0) >MIRRORPATH # Path for device containing mirrored>root >MIRROROFFSET 0 # Offset into mirrored device (Kbytes)> ># Physical Log Configuration > >PHYSDBS rootdbs # Location (dbspace) of physical log >PHYSFILE 10240 # Physical log file size (Kbytes)> ># Logical Log Configuration > >LOGFILES 94 # Number of logical log files >LOGSIZE 4000 # Logical log size (Kbytes)> ># Diagnostics > >MSGPATH /usr2/informix7/co2dcs.log # System message log file >path >CONSOLE /dev/console # System console message path>ALARMPROGRAM /usr2/informix7/log_full.sh # Alarm program path > ># System Archive Tape Device > >TAPEDEV /dev/rmt/0m # Tape device path >TAPEBLK 16 # Tape block size (Kbytes) >TAPESIZE 8192000 # Maximum amount of data to put on tape >(Kbytes)> ># Log Archive Tape Device > >LTAPEDEV /dev/rmt/0m # Log tape device path >LTAPEBLK 16 # Log tape block size (Kbytes) >LTAPESIZE 8192000 # Max amount of data to put on log tape >(Kbytes)> ># Optical > >STAGEBLOB # INFORMIX-OnLine/Optical staging area > ># System Configuration > >SERVERNUM 6 # Unique id corresponding to a OnLine>instance >DBSERVERNAME co2dcs # Name of default database server >DBSERVERALIASES # List of alternate dbservernames >NETTYPE ipcshm,1,512,CPU # Configure poll thread(s) for nettype >NETTYPE soctcp,1,128,NET # Configure poll thread(s) for nettype >DEADLOCK_TIMEOUT 60 # Max time to wait of lock in>distributed env. >RESIDENT 1 # Forced residency flag (Yes = 1, No = >0) > >MULTIPROCESSOR 1 # 0 for single-processor, 1 for>multi-processor >NUMCPUVPS 2 # Number of user (cpu) vps >SINGLE_CPU_VP 0 # If non-zero, limit number of cpu vps>to one > >NOAGE 0 # Process aging >AFF_SPROC 0 # Affinity start processor >AFF_NPROCS 0 # Affinity number of processors> ># Shared Memory Parameters > >LOCKS 200000 # Maximum number of locks >BUFFERS 20000 # Maximum number of shared buffers >NUMAIOVPS 11 # Number of IO vps >PHYSBUFF 128 # Physical log buffer size (Kbytes) >LOGBUFF 128 # Logical log buffer size (Kbytes)>LOGSMAX 100 # Maximum number of logical log files >CLEANERS 8 # Number of buffer cleaner processes >SHMBASE 0x0 # Shared memory base address >SHMVIRTSIZE 163840 # initial virtual shared memory segment>size >SHMADD 30000 # Size of new shared memory segments >(Kbytes) >SHMTOTAL 0 # Total shared memory (Kbytes). >0=>unlimited >CKPTINTVL 300 # Check point interval (in sec) >LRUS 16 # Number of LRU queues >LRU_MAX_DIRTY 5 # LRU percent dirty begin cleaning limit > >LRU_MIN_DIRTY 2 # LRU percent dirty end cleaning limit >LTXHWM 50 # Long transaction high water mark>percentage >LTXEHWM 60 # Long transaction high water mark >(exclusive) >TXTIMEOUT 0x12c # Transaction timeout (in sec) >STACKSIZE 128 # Stack size (Kbytes)> ># System Page Size ># BUFFSIZE - OnLine no longer supports this configuration parameter. ># To determine the page size used by OnLine on your platform ># see the last line of output from the command, 'onstat -b'. > > ># Recovery Variables ># OFF_RECVRY_THREADS: ># Number of parallel worker threads during fast recovery or an offline >restore. ># ON_RECVRY_THREADS: ># Number of parallel worker threads during an online restore. > >OFF_RECVRY_THREADS 10 # Default number of offline worker>threads >ON_RECVRY_THREADS 1 # Default number of online worker>threads > ># Data Replication Variables ># DRAUTO: 0 manual, 1 retain type, 2 reverse type >DRAUTO 0 # DR automatic switchover >DRINTERVAL 30 # DR max time between DR buffer flushes >(in sec) >DRTIMEOUT 30 # DR network timeout (in sec) >DRLOSTFOUND /dev/null # DR lost+found file path> ># Backup/Restore variables >BAR_ACT_LOG /tmp/bar_act.log >BAR_MAX_BACKUP 0 >BAR_RETRY 1 >BAR_NB_XPORT_COUNT 10 >BAR_XFER_BUF_SIZE 31> ># Read Ahead Variables >RA_PAGES 20 # Number of pages to attempt to read>ahead >RA_THRESHOLD 18 # Number of pages left before next group> ># DBSPACETEMP: ># OnLine equivalent of DBTEMP for SE. This is the list of dbspaces ># that the OnLine SQL Engine will use to create temp tables etc. ># If specified it must be a colon separated list of dbspaces that exist ># when the OnLine system is brought online. If not specified, or if ># all dbspaces specified are invalid, various ad hoc queries will create > ># temporary files in /tmp instead. > >DBSPACETEMP tmpdbs # Default temp dbspaces> ># DUMP*: ># The followin