Performance Problem with many buffer wait

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 rootdbspace 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 mirroredroot 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 pathALARMPROGRAM /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 OnLineinstance 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 indistributed env. RESIDENT 1 # Forced residency flag (Yes = 1, No = 0) MULTIPROCESSOR 1 # 0 for single-processor, 1 formulti-processor NUMCPUVPS 2 # Number of user (cpu) vps SINGLE_CPU_VP 0 # If non-zero, limit number of cpu vpsto 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 segmentsize 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 markpercentage 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 workerthreads ON_RECVRY_THREADS 1 # Default number of online workerthreads # 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 readahead 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 following parameters control the type of diagnostics information which # is preserved when an unanticipated error condition (assertion failure) occurs # during OnLine operations. # For DUMPSHMEM, DUMPGCORE and DUMPCORE 1 means Yes, 0 means No. DUMPDIR /var/adm/crash # Preserve diagnostics in this directory DUMPSHMEM 0 # Dump a copy of shared memory DUMPGCORE 0 # Dump a core imag