RE: Perfomance Tuning
When you say your checkpoints "should be 6 seconds", does that mean they
actually were 6 seconds at one time and increased to 10? If that is the
case, you need to identify what is causing this increase in checkpoint
duration.
Do you have an I/O bottleneck? Check sar -d during the checkpoints.
Is a user in a critical section at checkpoint time causing the checkpoint to
wait? Execute the following during a checkpoint:
select username,sid,pid,is_incrit from syssessions where is_incrit = 1;
The checkpoint will not proceed until there are no users in a critical
section.
Regarding someones suggestion that you add buffers. I wouldn't do that if
checkpoint duration is your concern because that will increase the
checkpoint duration. More buffers with the same number of LRUs will mean
more buffers left to be flushed during the checkpoint.
Regards,
Bill Dare
> -----Original Message-----
> From: bnyaguwa@okzim.co.zw [SMTP:bnyaguwa@okzim.co.zw]
> Sent: Wednesday, December 10, 2003 5:47 AM
> To: informix-list@iiug.org
> Subject: Perfomance Tuning
>
> 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
> # 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 /u/inf