The best way to size you cache is to determine the size of what's called
your working set of data, ie the volume of data that is typically accessed
during a typical day. If you can do this you are home free. Failing that,
you can monitor onstat -P over time and see how many buffers are being
swapped between partnums every 1.7 seconds to get an idea how many more
buffers you might need. The final and coarsest way would be to say that the
BTR is 6 times what it should be so you are likely to need to increase your
cache by a factor of 6x.
Art
Art S. Kagel
Oninit (www.oninit.com)
IIUG Board of Directors (art@iiug.org)
Disclaimer: Please keep in mind that my own opinions are my own opinions and
do not reflect on my employer, Oninit, the IIUG, nor any other organization
with which I am associated either explicitly or implicitly. Neither do
those opinions reflect those of other individuals affiliated with any entity
with which I am affiliated nor those of the entities themselves.
On Thu, Jul 16, 2009 at 5:35 PM, Brian Amstutz <
brian.amstutz@asburyseminary.edu> wrote:
> How does one go about 'estimating' this? The performance documentation
> says to "set the value of buffers to between 20 and 25 percent of the
> number of megabytes in physical memory." - since I have 8Gb total
> physical memory, if my math is correct, that means between 819200 and
> 1024000 buffers (for 20 - 25 percent) which seems awfully high. So if I
> bump this up, what kind of indicators do I need to be looking at to
> determine if I have TOO MANY buffers?
>
> Thanks!
>
> Brian
>
> > -----Original Message-----
> > From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
> Art S. Kagel
> > Sent: Wednesday, July 15, 2009 11:41 PM
> > To: ids@iiug.org
> > Subject: RE: Buffer Turnover Rate question [16415]
> >
> > The metrics reported by ratios are indicators that you need to
> investigate
> > further. Combining the very high BTR with the slightly low RAU i'd say
> that
> > you need more buffers. How many? Hard to say. The BTR indicates that
> > the answer may be as high as 6X the current cache. But you should try to
>
> > estimate your working set o data from application needs.
> >
> > Art
> >
> > -----Original Message-----
> > From: BRIAN AMSTUTZ <brian.amstutz@asburyseminary.edu>
> > Sent: Wednesday, July 15, 2009 2:15 PM
> > To: ids@iiug.org
> > Subject: Buffer Turnover Rate question [16409]
> >
> > HPUX 11vi2, 4x440MHz cpu, 8GB RAM, Informix 10.00.HC5
> >
> > I just recently downloaded the ratios.ksh script and started running it.
> I m
> > not noticing any performance problems as such but it seems like the BTR
> is
> > quite high. onstat -c and onstat -p output is included below. Anything
> to
> > worry about? Thanks! -bla
> >
> > ReadAhead Utilization (UR): 99.6735 %
> > Bufwaits Ratio(BR): 1.13657 %
> > Average Buffer Turnover Rate (BTR): 36.9059/HR
> > Stats reset 71:40:00 ago.
> >
> > IBM Informix Dynamic Server Version 10.00.HC5 -- On-Line -- Up 2 days
> 23:47:25
> > -- 591028 Kbytes
> >
> > Configuration File: /opt/informix/etc/onconf.cars
> > # Root Dbspace Configuration
> >
> > ROOTNAME root # Root dbspace name
> > ROOTPATH /opt/informix/dev/root.1
> >
> > # Path for device containing root dbspace
> > ROOTOFFSET 0 # Offset of root dbspace into device (Kbytes)
> > ROOTSIZE 1024000 # 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 root # Location (dbspace) of physical log
> > PHYSFILE 40960 # Physical log file size (Kbytes)
> >
> > # Logical Log Configuration
> >
> > LOGFILES 60 # Number of logical log files
> > LOGSIZE 14336 # Logical log size (Kbytes)
> > LOG_BACKUP_MODE MANUAL # 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
> > DBCREATE_PERMISSION root
> >
> > # 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 1 # 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 /opt/informix/Logs/cars.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 /opt/informix/etc/no_log.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/rmt/1m # Tape device path
> > TAPEBLK 256 # Tape block size (Kbytes)
> > TAPESIZE 0 # Maximum amount of data to put on tape (Kbytes)
> >
> > # Log Archive Tape Device
> >
> > LTAPEDEV /dev/rmt/2m # Log tape device path
> > LTAPEBLK 32 # Log tape block size (Kbytes)
> > LTAPESIZE 0 # Max amount of data to put on log tape (Kbytes)
> >
> > # Optical
> >
> > STAGEBLOB # Informix Dynamic Server staging area
> >
> > # System Configuration
> >
> > SERVERNUM 1 # Unique id corresponding to a OnLine instance
> > DBSERVERNAME daniel3 # Name of default database server
> > DBSERVERALIASES daniel3tcp,carsmain_tcp # List of alternate
> dbservernames
> > NETTYPE ipcshm,3,250,CPU # Configure poll thread(s) for nettype
> > NETTYPE soctcp,3,,NET # Configure poll thread(s) for nettype
> > DEADLOCK_TIMEOUT 60 # Max time to wait of lock in distributed env.
> >
> > MULTIPROCESSOR 1 # 0 for single-processor, 1 for multi-processor
> > SINGLE_CPU_VP 0 # If non-zero, limit number of cpu vps to one
> >
> > # Shared Memory Parameters
> > BUFFERPOOL
> > size=2K,buffers=100000,lrus=29,lru_min_dirty=2.000000,lru_max_dirty=
> > =4.000000
> > LOCKS 512000 # Maximum number of locks
> > PHYSBUFF 64 # Physical log buffer size (Kbytes)
> > LOGBUFF 32 # Logical log buffer size (Kbytes)
> > CLEANERS 29 # Number of buffer cleaner processes
> > SHMBASE 0x0 # Shared memory base address
> > SHMVIRTSIZE 321536 # initial virtual shared memory segment size
> > SHMADD 32768 # Size of new shared memory segments (Kbytes)
> > SHMTOTAL 0 # Total shared memory (Kbytes). 0=>unlimited
> > CKPTINTVL 900 # Check point interval (in sec)
> > TXTIMEOUT 0x12c # Transaction timeout (in sec)
> > STACKSIZE 512 # 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/LTXE=
> > HWM
> > # can be set to smaller values.
> > #
> > # If dynamic logging is off, LTXHWM/LTXEHWM need to be set to smaller
> value=
> > s
> > # to avoid long transaction rollback hanging the server due to lack of
> logi=
> > cal
> > # 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 0
> > LTXHWM 35
> > LTXEHWM 45
> >
> > # 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 /opt/informix/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 0,0 # 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 /tmp/bar_act.log # ON-Bar Log file - not in /tmp please
> > BAR_DEBUG_LOG /tmp/bar_dbug.log # ON-Bar Debug Log - not in /tmp please
> > BAR_MAX_BACKUP 0
> > BAR_RETRY 1
> > BAR_NB_XPORT_COUNT 10
> > BAR_XFER_BUF_SIZE 31
> > RESTARTABLE_RESTORE off
> > BAR_PROGRESS_FREQ 0
> >
> > # Informix Storage Manager variables
> > ISM_DATA_POOL ISMData
> > ISM_LOG_POOL ISMLogs
> >
> > # Read Ahead Variables
> > RA_PAGES 32 # Number of pages to attempt to read ahead
> > RA_THRESHOLD 28 # 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 temp0 # Default temp dbspaces
> >
> > # DUMP*:
> > # The following parameters control the type of diagnostics information
> whic=
> > h
> > # 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 /opt/informix/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 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 80 # Maximum allowed pdqpriority
> > DS_MAX_QUERIES 10 # Maximum number of decision support queries
> > DS_TOTAL_MEMORY 245760 # 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 0 # To hint the optimizer
> >
> > DIRECTIVES 1 # Optimizer DIRECTIVES ON (1/Default) or OFF (0)
> >
> > ONDBSPACEDOWN 0 # Dbspace down option: 0 = CONTINUE, 1 = ABORT, 2
> > = W=
> > AIT
> > 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 /opt/informix/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)=
> >
> >
> > #
> > # The following are default settings for enabling Java in the database.
> > # Replace all occurrences of /usr/informix with the value of
> /opt/informix.=
> >
> >
> > JVPJAVAHOME /opt/informix/extend/krakatoa/jre
> >
> > # JRE installation root directory
> > JVPHOME /opt/informix/extend/krakatoa # Krakatoa installation directory
> >
> > JVPPROPFILE /opt/informix/extend/krakatoa/.jvpprops # JVP property file
> > JVPLOGFILE /opt/informix/Logs/jvp.log # JVP log file.
> >
> > JDKVERSION 1.3 # JDK version supported by this server
> >
> > # The path to the JRE libraries relative to JVPJAVAHOME
> > JVPJAVALIB /lib/PA_RISC
> >
> > # The JRE libraries to use for the Java VM
> >
> > JVPJAVAVM hpi:server: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
> >
> /opt/informix/extend/krakatoa/krakatoa_g.jar:/opt/informix/extend/krakatoa
> /=
> > jdbc_g.jar
> > JVPCLASSPATH
> >
> /opt/informix/extend/krakatoa/krakatoa.jar:/opt/informix/extend/krakatoa/j
> d=
> > bc.jar
> > RESIDENT 0 # Forced residency flag (Yes = 1, No = 0)
> > EXTSHMADD 8192 # Size of new extension shared memory segments (Kbytes)
> > ONLIDX_MAXMEM 5120 # Per pool per index (Kbytes)
> > LISTEN_TIMEOUT 10 # Timeout (in Seconds)
> > IFX_FOLDVIEW 0 # fold multiple tables or union all view with ansi joins
> > NUMCPUVPS 3 # Number of user (cpu) vps
> > NOAGE 0 # Process aging
> > AFF_SPROC 0 # Affinity start processor
> > AFF_NPROCS 0 # Affinity number of processors
> > NUMAIOVPS 3 # Number of IO vps
> >
> > DD_HASHSIZE 101 # Set 5/5/2008 as per B.Pang - Abtech sys
> > DD_HASHMAX 20
> >
> > IBM Informix Dynamic Server Version 10.00.HC5 -- On-Line -- Up 2 days
> 23:58=
> > :42
> > -- 591028 Kbytes
> >
> > Profile
> > dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached
> > 25948698 84051523 3811712387 99.33 1153692 7544307 181137449 99.55
> >
> > isamtot open start read write rewrite delete commit rollbk
> > 2627748403 90544476 251539174 1563253711 58314988 2347689 329232 270095
> > 222=
> >
> >
> > gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs
> > 0 0 0 0 0 0 0
> >
> > ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes
> > 0 0 0 115043.47 12873.40 365 734
> >
> > bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans
> > 3011346 41 2769673454 0 0 295 6592869 14355320
> >
> > ixda-RA idx-RA da-RA RA-pgsused lchwaits
> > 8983783 1129973 7040984 17098680 2620933
> >
> >
> **************************************************************************
> *=
> > ****
> > Forum Note: Use "Reply" to post a response in the discussion forum.
> >
> >
> >
> **************************************************************************
> *****
> > Forum Note: Use "Reply" to post a response in the discussion forum.
>
>
>
> *******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.
>
>
--001636c5b35690142a046eda0ddd
