Re: Perfomance Tuning

This may help read performance but it will do nothing do speed up checkpoints. In fact increasing the number of buffers could make for longer checkpoints because it is less likely that LRU_MAX_DIRTY will have kicked in between checkpoints, so there's likely to be more data left to write. Some possible causes of long checkpoints include: - Having all the write-intensive stuff on the same disks - Allocating the chunks in such an order that more than one page cleaner / AIO VP is hacking away at chunks on the same disk during a checkpoint (watch onstat -F while the checkpoint is running) - Using RAID 5 (AAaaaaarrrgggghhhh!) - Using cooked files (AAaaaaarrrgggghhhh!) - Configuring Logical Volumes in such a way as to exacerbate the above write contention problems - Poor fragmentation strategy, or having indexes on the same disk as the corresponding table. - Bad code (e.g. generating unnecessary temp tables) - Your system just getting busier. Andy "Olmedo Monteverde" <o.monteverde@naville-livre.ch> wrote in message news:<br786b$rs2$1@rex.ip-plus.net>... > Hi, > You could increase the buffers number. A memory size of 4Gb allows you to do > so. In our case, we have 700'000 buffers (2048b each), which means that we > almost reached IDS limits of current version (IDS 7.30, soon migrating to > 9.40). We also declared strategic tables and indexes as resident in memory, > which increased performances. Put attention to tables' extents. That has a > major impact on performances as well. > HTH, > OM > > "Bonny" <bnyaguwa@okzim.co.zw> a 'crit dans le message de > news:699af31f.0312100246.2b806c4@posting.google.com... > > I have IDS 7.31 running on HP-UX 11.0 and 4 Gig of memory. > > > > I have a 40 Gig database with on average 260 users and at peak about > > 315 users. > > I want to tune my database , as it has shown signs of slowing down > > recently. > > Checkpoints are taking on average 10 seconds,under normal processing > > there should be 6 seconds. > > I have posted my onconfig file,onstat -p .What parameters should i > > consider for tuning both from the Informix side and Unix side. > > > > Onconfig > > > > > #************************************************************************** > > # > > # INFORMIX SOFTWARE, INC. > > # > > # Title: onconfig.std > > # Description: Informix Dynamic Server Configuration Parameters > > # > > > #************************************************************************** > > > > # Root Dbspace Configuration > > > > ROOTNAME rootdbs # Root dbspace name > > ROOTPATH /dev/rootdbs # Path for device containing root> > dbspace > > ROOTOFFSET 0 # Offset of root dbspace into device > > (Kbytes) > > ROOTSIZE 1000000 # 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 250000 # Physical log file size (Kbytes)> > > > # Logical Log Configuration > > > > LOGFILES 30 # Number of logical log files > > LOGSIZE 5000 # Logical log size (Kbytes)> > > > # Diagnostics > > > > MSGPATH /u/informix/online.log # System message log file path > > CONSOLE /dev/console # System console message path > > ALARMPROGRAM /u/informix/etc/log_full.sh # Alarm program path> > SYSALARMPROGRAM /u/informix/etc/evidence.sh # System Alarm program > > path > > TBLSPACE_STATS 0> > > > # System Archive Tape Device > > > > TAPEDEV /dev/rmt/c8t3d0BEST # Tape device path > > TAPEBLK 6144 # Tape block size (Kbytes) > > TAPESIZE 80000000 # Maximum amount of data to put on > > tape (Kbytes)> > > > # Log Archive Tape Device > > > > LTAPEDEV /dev/rmt/1m # Log tape device pat > > LTAPEBLK 1024 # Log tape block size (Kbytes) > > LTAPESIZE 4000000 # Max amount of data to put on log > > tape (Kbytes)> > > > # Optical > > > > STAGEBLOB # Informix Dynamic Server/Optical > > staging area > > > > # System Configuration > > > > SERVERNUM 1 # Unique id corresponding to a Dynamic> > Server instance > > DBSERVERNAME ok_srvr # Name of default database server > > DBSERVERALIASES ok_tcp # List of alternate dbservernames > > NETTYPE ipcshm,1,500,CPU # Configure poll thread(s) for> > nettype > > NETTYPE soctcp,1,5,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 1 # Process aging > > AFF_SPROC 0 # Affinity start processor > > AFF_NPROCS 0 # Affinity number of processors> > > > # Shared Memory Parameters > > > > LOCKS 400000 # Maximum number of locks > > BUFFERS 200000 # Maximum number of shared buffers > > NUMAIOVPS 8 # 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 127 # Number of buffer cleaner processes > > SHMBASE 0x0 # Shared memory base address > > SHMVIRTSIZE 300000 # initial virtual shared memory> > segment size > > SHMADD 40000 # Size of new shared memory segments > > (Kbytes) > > SHMTOTAL 0 # Total shared memory (Kbytes). > > 0=>unlimited > > CKPTINTVL 360 # Check point interval (in sec) > > LRUS 127 # Number of LRU queues > > LRU_MAX_DIRTY 1 # LRU percent dirty begin cleaning> > limit > > LRU_MIN_DIRTY 0 # 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 64 # Stack size (Kbytes)> > > > # System Page Size > > # BUFFSIZE - Dynamic Server no longer supports this configuration > > parameter. > > # To determine the page size used by Dynamic Server on your > > platform > > #