Database performance 1

[msmy]

Hi,
Want to know how to/what steps to do to increase my database performance. My users always complain the system is slow. I suspect my database have problem. My server using HP-UX using IDS 7.2 version.

 

[gheist]

can you show us $INFORMIXDIR/etc/onconfig

and output of

onstat -p

and

onstat -u (omitting non-informix users of course)

 

[gheist]

can you show us $INFORMIXDIR/etc/onconfig

and output of

onstat -p

and

onstat -u (omitting non-informix usernames of course)

 

[msmy]

$INFORMIXDIR/etc/onconfig

# Root Dbspace Configuration

ROOTNAME rootdbs # Root dbspace name
ROOTPATH /dev/vg01/rlvol2 # Path for device containing root dbspace
ROOTOFFSET 0 # Offset of root dbspace into device (Kbytes)
ROOTSIZE 500000 # 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 20000 # Physical log file size (Kbytes)

# Logical Log Configuration

LOGFILES 25 # Number of logical log files
LOGSIZE 10000 # Logical log size (Kbytes)

# Diagnostics

MSGPATH /informix/online.log # System message log file path
CONSOLE /dev/console # System console message path
ALARMPROGRAM /informix/etc/no_log.sh # Alarm program path
TBLSPACE_STATS 1

# System Archive Tape Device

TAPEDEV /dev/rmt/c1t0d0DDS # Tape device path
TAPEBLK 1024 # Tape block size (Kbytes)
TAPESIZE 2000000 # Maximum amount of data to put on tape (Kbytes)

# Log Archive Tape Device

LTAPEDEV /dev/null # Log tape device path
LTAPEBLK 1024 # Log tape block size (Kbytes)
LTAPESIZE 200000 # 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 CODA # Name of default database server
DBSERVERALIASES ODBC # List of alternate dbservernames
DEADLOCK_TIMEOUT 60 # Max time to wait of lock in distributed env.
RESIDENT 0 # 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 700000 # Maximum number of locks
BUFFERS 300000 # Maximum number of shared buffers
NUMAIOVPS 2 # Number of IO vps
PHYSBUFF 1000 # Physical log buffer size (Kbytes)
LOGBUFF 1000 # Logical log buffer size (Kbytes)
LOGSMAX 25 # Maximum number of logical log files
CLEANERS 20 # Number of buffer cleaner processes
SHMBASE 0x0 # Shared memory base address
SHMVIRTSIZE 20480 # initial virtual shared memory segment size
SHMADD 20480 # Size of new shared memory segments (Kbytes)
SHMTOTAL 0 # Total shared memory (Kbytes). 0=>unlimited
CKPTINTVL 300 # Check point interval (in sec)
LRUS 30 # Number of LRU queues
LRU_MAX_DIRTY 10 # LRU percent dirty begin cleaning limit
LRU_MIN_DIRTY 5 # 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 32 # 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 /informix/etc/dr.lostfound # DR lost+found file path

# CDR Variables
CDR_LOGBUFFERS 2048 # size of log reading buffer pool (Kbytes)
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)

# 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

# Informix Storage Manager variables
# update $INFORMIXDIR/bin/onbar. Change to
# ism_catalog -create_bootstrap -pool <new name>

# Read Ahead Variables
RA_PAGES 50 # Number of pages to attempt to read ahead
RA_THRESHOLD 20 # Number of pages left before next group

# DBSPACETEMP:
# Dynamic Server equivalent of DBTEMP for SE. This is the list of dbspaces
# that the Dynamic Server SQL Engine will use to create temp tables etc.
# If specified it must be a colon separated list of dbspaces that exist
# when the Dynamic Server 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 tempdb # 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 Dynamic Server operations.
# For DUMPSHMEM, DUMPGCORE and DUMPCORE 1 means Yes, 0 means No.

DUMPDIR /tmp # 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 Dynamic Server)
DUMPCNT 1 # Number of shared memory or gcore dumps for
# a single user's session

FILLFACTOR 90 # Fill factor for building indexes

# method for Dynamic Server 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 # Maximum number of decision support queries
DS_TOTAL_MEMORY # Decision support memory (Kbytes)
DS_MAX_SCANS 1048576 # Maximum number of decision support scans
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
# &quot;repeatable read&quot;, 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

ONDBSPACEDOWN 0 # Dbspace down option: 0 = CONTINUE, 1 = ABORT, 2 = WAIT
LBU_PRESERVE 0 # Preserve last log for log backup
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

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

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

# Status of restartable restore
NETTYPE soctcp,2,50,NET # Configure poll thread(s) for nettype

onstat -p

INFORMIX-OnLine Version 7.24.UC8A -- On-Line -- Up 22 days 18:49:13 -- 720944s

Profile
dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached
2799210 29897002 190922241 98.53 2053186 15556560 65479791 96.86

isamtot open start read write rewrite delete commit rollbk
1955469919 9534231 31840189 1821321456 5301617 99417 717621 80306 47

ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes
0 0 0 255927.75 10219.10 2066 13052

bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans
279101 354 1702964275 42 0 584 4311246 8629245

ixda-RA idx-RA da-RA RA-pgsused lchwaits
634029 538 495103 1125691 19289775

onstat -u

ea49ad98 Y--P--- 10482 coda - eaea3078 0 1 0 226
ea49b618 ---P--D 11 informix - 0 0 0 0 0
ea49ba58 ---PR-- 10502 coda - 0 0 1 0 1
ea49d3d8 Y--P--- 10494 kid ttyp5 eb68a708 0 1 0 0
ea49e918 Y--P--- 10480 coda - eb5ae170 0 1 0 0
ea49ed58 Y--P--- 10335 coda TIGER eb523130 0 1 0 0
ea49fa18 ---PR-- 10498 coda - 0 0 1 0 1
ea4a0f58 Y--P--- 10481 coda - eb5ae990 0 1 0 0
ea4a1398 Y--P--- 10474 halipah ttyp3 ea6f4538 0 2 1284 763
ea4a2498 Y--P--- 10478 zarina ttyp4 eb5ad078 0 2 0 3
ea4a28d8 Y--P--- 10477 zarina ttyp4 eb6860b8 0 1 0 0
ea4a3158 Y--P--- 10492 coda - eb6896c8 0 1 4 30
ea4a39d8 Y--P--- 10483 coda - eaeac858 0 1 374 453
ea4a4258 Y--P--- 10476 coda - eb685898 0 1 73 704
ea4a5358 Y--P--- 10495 kid ttyp5 ea6dad10 0 2 0 5
ea4a5798 ---PR-- 10497 coda - 0 0 1 0 1
ea4a6018 ---P--- 10500 coda - 0 0 1 0 1
ea4a6458 Y--P--- 10479 coda - eb5ad950 0 1 2428 2428
ea4a7118 Y--P--- 10470 halipah ttyp3 eb585078 0 1 0 0
ea4a8218 Y--P--- 10484 coda - eaec3078 0 1 0 0
ea4a8658 Y--P--- 10496 coda - ea7786a8 0 1 0 0
ea4a9318 Y--P--- 10493 coda - eb689ee8 0 1 17 53
ea4a9fd8 ---PR-- 10501 coda - 0 0 1 0 1
45 active, 128 total, 102 maximum concurrent

 

[gheist]

Disk IO is slow

NUMAIOVPS <Leave it blank>
RA_PAGES <Leave it blank>
RA_THRESHOLD <Leave it blank>

USEOSTIME 1 <If you ever will use current()>
MAX_PDQPRIORITY 90 <If you plan to UPDATE while others SELECT>

and move
PHYSDBS rootdbs
PHYSFILE 20000
to independent disk (do not store it in rootdbs)
tool is onparams (which requres reboot)

Check /informix/online.log if checkpints are not longer than 10 seconds and decrease
CKPTINTVL 300

OK now your database runs smoothly

Reduce BUFFERS and LOCKS if 720944 KiloBytes is about half your RAM

Rest is great assuming you have 2 real CPUs

 

[gheist]

UPDATE STATISTICS MEDIUM; is fast way of reorganizing databases

or (monthly/weekly)

UPDATE STATISTICS HIGH;

if it complains about free space to write rows-

make
DBSPACETEMP tempdb
larger(add another,bigger)

There is the way of optimizing table fragments (EXTENT.NEXT) but it involves recreating database or tables

 

[msmy]

How you get figure 720944 KiloBytes ?

 

[gheist]

from first line of onstat

try
onstat -

the only line will be self-explaining

 

[msmy]

My server only have 512 MB RAM.So what should I do ?

 

[gheist]

You should lower LOCKS and BUFFERS avout three times

eg

LOCKS 200000
BUFFERS 100000

It may complain about missing locks (hey - deadlocks are bad - it is some misdesign of client apps) - then raise it and lower buffers


I dont know how to get LOCKS &quot;Maximum&quot;
but current locks are in database sysmaster in syslocks table

you may check your OS *stat commands to see if you dont need extra ram to relax your disks

 

[gheist]

Cause of deadlocks / too many locks can be PAGE lock mode on intensively used tables ( tip : use ROW locking)

 

[Gimbert]

too many sequential scans for OLTP BD (onstat -p), rewiew UPDATE STATISTICS policy and indexes in your tables.

 

[davidgrove]

gheist,

An informative thread. Good to &quot;peer over the shoulder&quot; of an experienced Informix DBA.

What values did you use to determine that &quot;DISK IO is slow&quot;?

Thanks,

DG