Re: Performance Problem with many buffer wait

Try it with more BUFFERS. Also check my posting and the answers here. Subject: "bufwaits and RA_PAGES" Regards Wolf D. Pichler Grace Kan wrote: > 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