Re: Problem with Long Checkpoints

Jeffery, Since the HW and DB configurations are the same, the independent variable seems to be the application code. If that is the case here are some suggestions. "Standardize" as many routines as you can. They could then be optimized(and maybe stored as SPL). This would eliminate variations by the programming staff as well. You will still find some amount of the execution time based on the difference of the applications. But at least you will have eliminated individual cases of non-optimized code. Paul Storm > From owner-informix-list@iiug.org Tue Jun 1 14:41:52 1999 > Date: Tue, 1 Jun 1999 11:31:50 -0700 (PDT) > From: Jeffrey Screws <jeff_screws@yahoo.com> > Subject: Problem with Long Checkpoints > To: informix-list@iiug.org > MIME-Version: 1.0 > > Hello, > > I have a problem with long checkpoint durations on some of my systems. > Let me describe my environment. > > HW Environment: > > 7 HP 9000 K460 boxes w/ > HP-UX 10.20 > 768mb or 1 gig of ram on each box > 16 to 24 - 2.1 gb disks on each box depending on the number of Informix > instances. Each instance has 10 dbspaces on only 2 mirrored pairs(4 > disks in total). I'm sure this is at least part of the problem. But > I'm sure there is some tuning the can help? > > DB Environment > > 1 to 4 instances on each box. The database is identical on each > instance, (except for the contents of course!), and is roughly 4 gb is > total size. Theses are by no stretch large databases! All storage is > mirrored using HP LVM mirroring. Each instances probably has an > average of 30 users hitting them 24x7. The application runs on the > box also, so each user is telnetting in and running the 4GL app locally > through shared memory connections. > > Here is the problem. On the best performing db instance the checkpoint > duration is 2 or 3 seconds at every CKPTINTVL. On the worst > performing instance the duration is usually around 8 or 9 seconds and > sometimes up to 25 seconds. I am including all the info that I saw Art > Kagel ask of someone a few days ago. Hope this isn't tooooooo much > info. > > All suggestions welcome(and very much needed!) > > Thanks....Jeff S. > > > INFORMIX-OnLine Version 7.24.UC5 -- On-Line -- Up 4 days 11:53:14 -- > 192072 Kbytes > > Configuration File: /informix/etc/onconfig_lff > #************************************************************************** > # > # INFORMIX SOFTWARE, INC. > # > # Title: onconfig.std > # Description: INFORMIX-OnLine Configuration Parameters > # > #************************************************************************** > > # Root Dbspace Configuration > > ROOTNAME rootdbs # Root dbspace name> ROOTPATH /links/ROOTDBS_LFF # Path for device containing root > dbspace > ROOTOFFSET 0 # Offset of root dbspace into device > (Kbytes) > ROOTSIZE 128000 # 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 phylog # Location (dbspace) of physical log > PHYSFILE 25000 # Physical log file size (Kbytes)> > # Logical Log Configuration > > LOGFILES 30 # Number of logical log files > LOGSIZE 10000 # Logical log size (Kbytes)> > # Diagnostics > > MSGPATH /informix/online.log_lff # System message log file path > CONSOLE /dev/console # System console message path > ALARMPROGRAM /usr/local/publix/publix.infx_alarm> > # System Archive Tape Device > > #TAPEDEV /dev/null > TAPEDEV /dev/rmt/0m # Tape device path > #TAPEDEV /bu_lff/ontape_post_reorg.lff # Tape device path > TAPEBLK 16 # Tape block size (Kbytes) > TAPESIZE 5000000 # Maximum amount of data to put on tape > (Kbytes)> > # Log Archive Tape Device > > LTAPEDEV /bu_lff/log.lff # Log tape device path > #LTAPEDEV /dev/rmt/0m # Log tape device path > LTAPEBLK 16 # Log tape block size (Kbytes) > LTAPESIZE 5000000 # Max amount of data to put on log tape > (Kbytes)> > # Optical > > STAGEBLOB ,1 # INFORMIX-OnLine/Optical staging area > > # System Configuration > > SERVERNUM 0 # Unique id corresponding to a OnLine> instance > DBSERVERNAME onlineipc_lff # Name of default database server > DBSERVERALIASES onlinetcp_lff # List of alternate dbservernames > NETTYPE ipcshm,1,100,CPU # Override sqlhosts > NETTYPE soctcp,1,75,NET # Override sqlhosts > DEADLOCK_TIMEOUT 300 # 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 4 # 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 300000 # Maximum number of locks > BUFFERS 60000 # Maximum number of shared buffers > NUMAIOVPS 20 # Number of IO vps > PHYSBUFF 260 # Physical log buffer size (Kbytes) > LOGBUFF 32 # Logical log buffer size (Kbytes)> LOGSMAX 50 # Maximum number of logical log files > CLEANERS 50 # Number of buffer cleaner processes > SHMBASE 0x0 # Shared memory base address > SHMVIRTSIZE 48000 # initial virtual shared memory segment> size > SHMADD 16384 # Size of new shared memory segments > (Kbytes) > SHMTOTAL 650000 # Total shared memory (Kbytes). > 0=>unlimited > CKPTINTVL 3000 # Check point interval (in sec) > LRUS 50 # Number of LRU queues > LRU_MAX_DIRTY 2 # LRU percent dirty begin cleaning> limit > LRU_MIN_DIRTY 1 # LRU percent dirty end cleaning limit > LTXHWM 40 # Long transaction high water mark> percentage > LTXEHWM 50 # Long transaction high water mark > (exclusive) > TXTIMEOUT 0x12c # Transaction timeout (in sec) > STACKSIZE 48 # 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'. > > > # Reco