IDS Forum

latch waits and what to do about them

Posted By: BILL MARSHALL
Date: Friday, 6 July 2007, at 6:54 a.m.

System has been up and stable in OLTP from &AM to 12 Midinght and batch from midnight till 7 AM. However it seems like the latch waits are high.

Latch waits go as high as 3875

System is stable but I always want more speed. (as long as it does not effect stability.)

Here is onconfig

I am running IBM Informix Dynamic Server Version 10.00.UC3 Workgroup Server on a HP dual processor Intel machine 8 Gig of memory
Red Hat Enterprise Linux ES release 3
Kernel 2.4.21-47.ELsmp on an i686

onconfig looks like

#**************************************************************************
#
# Licensed Material - Property Of IBM
#
# "Restricted Materials of IBM"
#
# IBM Informix Dynamic Server
# (c) Copyright IBM Corporation 1996, 2005 All rights reserved.
#
# Title: onconfig.std
# Description: IBM Informix Dynamic Server Configuration Parameters
#
#**************************************************************************

# Root Dbspace Configuration

ROOTNAME rootdbs # Root dbspace name
ROOTPATH /dev/cciss/inforaw1 # Path for device containing root dbspace
ROOTOFFSET 0 # Offset of root dbspace into device (Kbytes)
ROOTSIZE 8000000 # 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 40000 # Physical log file size (Kbytes)

# Logical Log Configuration

LOGFILES 15 # Number of logical log files
LOGSIZE 8000 # Logical log size (Kbytes)
LOG_BACKUP_MODE CONT # Logical log backup mode (MANUAL, CONT)

# Security
# DBCREATE_PERMISSION:
# By default any user can create a database. Uncomment DBCREATE_PERMISSON to
# limit database creation to a specific user. Add a new DBCREATE_PERMISSION
# line for each permitted user.

#DBCREATE_PERMISSION informix

# IFX_EXTEND_ROLE:
# 0 => Disable use of EXTEND role to control who can register
# external routines. This is the default behaviour.
# 1 => Enable use of EXTEND role to control who can register
# external routines.

IFX_EXTEND_ROLE 0 # To control the usage of EXTEND role.

# Tablespace Tablespace Configuration in Root Dbspace

TBLTBLFIRST 0 # First extent size (Kbytes) (0 = default)
TBLTBLNEXT 0 # Next extent size (Kbytes) (0 = default)

# Diagnostics

MSGPATH /informix10.0.uc3/online1204.log # System message log file path
CONSOLE /dev/console # System console message path

# To automatically backup logical logs, edit alarmprogram.sh and set
# BACKUPLOGS=Y
ALARMPROGRAM /informix10.0.uc3/etc/alarmprogram.sh # Alarm program path
ALRM_ALL_EVENTS 0 # Triggers ALARMPROGRAM for any event occur
TBLSPACE_STATS 1 # Maintain tblspace statistics

# System Archive Tape Device

TAPEDEV /dev/st0 # Tape device path
#TAPEDEV /dev/null # Tape device path
TAPEBLK 64 # Tape block size (Kbytes)
TAPESIZE 47201280 # Maximum amount of data to put on tape (Kbytes)

# Log Archive Tape Device

#LTAPEDEV /dev/tapedev # Log tape device path
LTAPEDEV /dev/null # Log tape device path
LTAPEBLK 32 # Log tape block size (Kbytes)
LTAPESIZE 10240 # Max amount of data to put on log tape (Kbytes)

# Optical

STAGEBLOB # Informix Dynamic Server staging area

# System Configuration

SERVERNUM 0 # Unique id corresponding to a OnLine instance
DBSERVERNAME db3v124_shm # Name of default database server
DBSERVERALIASES db3v124fast # List of alternate dbservernames
DBSERVERALIASES db3v124link # List of alternate dbservernames
NETTYPE soctcp,2,100,NET # Configure poll thread(s) for nettype
NETTYPE ipcshm,1,250,CPU # Configure poll thread(s) for nettype
DEADLOCK_TIMEOUT 600 # 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 3 # 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 1 # Affinity start processor
AFF_NPROCS 3 # Affinity number of processors

# Shared Memory Parameters

LOCKS 200000 # Maximum number of locks
NUMAIOVPS 16 # Number of IO vps
PHYSBUFF 128 # Physical log buffer size (Kbytes)
LOGBUFF 64 # Logical log buffer size (Kbytes)
CLEANERS 20 # Number of buffer cleaner processes
SHMBASE 0x44000000L # Shared memory base address
#SHMVIRTSIZE 8192 # initial virtual shared memory segment size
SHMVIRTSIZE 131072 # initial virtual shared memory segment size
SHMADD 32768 # Size of new shared memory segments (Kbytes)
#SHMADD 64000 # Size of new shared memory segments (Kbytes)
SHMTOTAL 0 # Total shared memory (Kbytes). 0=>unlimited
CKPTINTVL 300 # Check point interval (in sec)
TXTIMEOUT 300 # Transaction timeout (in sec)
#TXTIMEOUT 60 # Transaction timeout (in sec)
#STACKSIZE 32 # Stack size (Kbytes)
STACKSIZE 128 # Stack size (Kbytes)

# Dynamic Logging
# DYNAMIC_LOGS:
# 2 : server automatically add a new logical log when necessary. (ON)
# 1 : notify DBA to add new logical logs when necessary. (ON)
# 0 : cannot add logical log on the fly. (OFF)
#
# When dynamic logging is on, we can have higher values for LTXHWM/LTXEHWM,
# because the server can add new logical logs during long transaction rollback.
# However, to limit the number of new logical logs being added, LTXHWM/LTXEHWM
# can be set to smaller values.
#
# If dynamic logging is off, LTXHWM/LTXEHWM need to be set to smaller values
# to avoid long transaction rollback hanging the server due to lack of logical
# log space, i.e. 50/60 or lower.
#
# In case of system configured with CDR, the difference between LTXHWM and
# LTXEHWM should be atleast 30% so that we could minimize log overrun issue.

DYNAMIC_LOGS 2
LTXHWM 70
LTXEHWM 80

# 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 /informix10.0.uc3/etc/dr.lostfound # DR lost+found file path
DRIDXAUTO 0 # DR automatic index repair. 0=off, 1=on

# CDR Variables
CDR_EVALTHREADS 1,2 # evaluator threads (per-cpu-vp,additional)
CDR_DSLOCKWAIT 5 # DS lockwait timeout (seconds)
CDR_QUEUEMEM 4096 # Maximum amount of memory for any CDR queue (Kbytes)
CDR_NIFCOMPRESS 0 # Link level compression (-1 never, 0 none, 9 max)
CDR_SERIAL 0 # Serial Column Sequence
CDR_DBSPACE # dbspace for syscdr database
CDR_QHDR_DBSPACE # CDR queue dbspace (default same as catalog)
CDR_QDATA_SBSPACE # List of CDR queue smart blob spaces

# CDR_MAX_DYNAMIC_LOGS
# -1 => unlimited
# 0 => disable dynamic log addition
# >0 => limit the no. of dynamic log additions with the specified value.
# Max dynamic log requests that CDR can make within one server session.

CDR_MAX_DYNAMIC_LOGS 0 # Dynamic log addition disabled by default

# Backup/Restore variables
BAR_ACT_LOG /usr/informix/bar_act.log # ON-Bar Log file - not in /tmp please
BAR_DEBUG_LOG /usr/informix/bar_dbug.log # ON-Bar Debug Log - not in /tmp please
BAR_MAX_BACKUP 0
BAR_RETRY 1
BAR_NB_XPORT_COUNT 20
BAR_XFER_BUF_SIZE 31
RESTARTABLE_RESTORE ON
BAR_PROGRESS_FREQ 0

# Informix Storage Manager variables
ISM_DATA_POOL ISMData
ISM_LOG_POOL ISMLogs

# Read Ahead Variables
RA_PAGES 64 # Number of pages to attempt to read ahead
RA_THRESHOLD 32 # 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 tmpchunk # 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 /tmp1204 # Preserve diagnostics in this directory
DUMPSHMEM 1 # Dump a copy of shared memory
DUMPGCORE 0 # Dump a core image using 'gcore'
DUMPCORE 0 # Dump a core image (Warning:this aborts OnLine)
DUMPCNT 1 # Number of shared memory or gcore dumps for

# a single user's session

FILLFACTOR 90 # Fill factor for building indexes

# method for OnLine to use when determining current time
USEOSTIME 0 # 0: use internal time(fast), 1: get time from OS(slow)

# Parallel Database Queries (pdq)
MAX_PDQPRIORITY 100 # Maximum allowed pdqpriority
DS_MAX_QUERIES 2 # Maximum number of decision support queries
DS_TOTAL_MEMORY 256 # Decision support memory (Kbytes)
DS_MAX_SCANS 1048576 # Maximum number of decision support scans
DS_NONPDQ_QUERY_MEM 128 # Non PDQ query memory (Kbytes)
DATASKIP off # List of dbspaces to skip

# OPTCOMPIND
# 0 => Nested loop joins will be preferred (where
# possible) over sortmerge joins and hash joins.
# 1 => If the transaction isolation mode is not
# "repeatable read", optimizer behaves as in (2)
# below. Otherwise it behaves as in (0) above.
# 2 => Use costs regardless of the transaction isolation
# mode. Nested loop joins are not necessarily
# preferred. Optimizer bases its decision purely
# on costs.
OPTCOMPIND 2 # To hint the optimizer

DIRECTIVES 1 # Optimizer DIRECTIVES ON (1/Default) or OFF (0)

ONDBSPACEDOWN 2 # Dbspace down option: 0 = CONTINUE, 1 = ABORT, 2 = WAIT
OPCACHEMAX 0 # Maximum optical cache size (Kbytes)

# HETERO_COMMIT (Gateway participation in distributed transactions)
# 1 => Heterogeneous Commit is enabled
# 0 (or any other value) => Heterogeneous Commit is disabled
HETERO_COMMIT 0

SBSPACENAME # Default smartblob space name - this is where blobs

# go if no sbspace is specified when the smartblob is

# created. It is also used by some datablades as

# the location to put their smartblobs.
SYSSBSPACENAME # Default smartblob space for use by the Informix

# Server. This is used primarily for Informix Server

# system statistics collection.

BLOCKTIMEOUT 3600 # Default timeout for system block
SYSALARMPROGRAM /informix10.0.uc3/etc/evidence.sh # System Alarm program path

# Optimization goal: -1 = ALL_ROWS(Default), 0 = FIRST_ROWS
OPT_GOAL -1

ALLOW_NEWLINE 0 # embedded newlines(Yes = 1, No = 0 or anything but 1)

#Create Index Online Shared Memory usage limitation
ONLIDX_MAXMEM 5120 # Per pool per index (Kbytes)

#Timeout for client connection request
LISTEN_TIMEOUT 10 # Timeout (in Seconds)

#Following are the deprecated configuration parameters, instead of these
#use BUFFERPOOL configuration parameter
#BUFFERS, LRUS, LRU_MIN_DIRTY, LRU_MAX_DIRTY
#
# The following are default settings for enabling Java in the database.
# Replace all occurrences of /usr/informix with the value of $INFORMIXDIR.

#VPCLASS jvp,num=1 # Number of JVPs to start with

JVPJAVAHOME /informix10.0.uc3/extend/krakatoa/jre # JRE installation root directory
JVPHOME /informix10.0.uc3/extend/krakatoa # Krakatoa installation directory

JVPPROPFILE /informix10.0.uc3/extend/krakatoa/.jvpprops # JVP property file
JVPLOGFILE /informix10.0.uc3/jvp.log # JVP log file.

JDKVERSION 1.3 # JDK version supported by this server

# The path to the JRE libraries relative to JVPJAVAHOME
JVPJAVALIB /bin

# The JRE libraries to use for the Java VM

JVPJAVAVM jsig:hpi:jvm:java:net:zip:jpeg

# use JVPARGS to change Java VM configuration
#To display jni call
#JVPARGS -verbose:jni

# Classpath to use upon Java VM start-up (use _g version for debugging)

#JVPCLASSPATH /usr/informix/extend/krakatoa/krakatoa_g.jar:/usr/informix/extend/krakatoa/jdbc_g.jar
#JVPCLASSPATH /usr/informix/extend/krakatoa/krakatoa.jar:/usr/informix/extend/krakatoa/jdbc.jar
JVPCLASSPATH /informix10.0.uc3/extend/krakatoa/krakatoa.jar:/informix10.0.uc3/extend/krakatoa/jdbc.jar

# The following parameters are related to the buffer pool
#BUFFERPOOL default,buffers=800000,lrus=8,lru_min_dirty=20.000000,lru_max_dirty=25.000000
BUFFERPOOL default,buffers=800000,lrus=8,lru_min_dirty=0.000010,lru_max_dirty=25.000000
#BUFFERPOOL size=2K,buffers=800000,lrus=8,lru_min_dirty=20.000000,lru_max_dirty=25.000000
BUFFERPOOL size=2K,buffers=800000,lrus=8,lru_min_dirty=0.000010,lru_max_dirty=10.000000

thanks for your opinion

Messages In This Thread

• latch waits and what to do about them
  BILL MARSHALL -- Friday, 6 July 2007, at 6:54 a.m.
  • Re:latch waits and what to do about them
    ART KAGEL, BLOOMBERG/ 731 LEXIN -- Friday, 6 July 2007, at 7:10 a.m.

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