IDS Forum

Re: Application slow and data not saved

Posted By: Peter_Logan@spartanstores.com
Date: Thursday, 12 November 2009, at 8:25 a.m.

In Response To: Re: Application slow and data not saved (Art Kagel)

Art,

have you scripted the calculation of these values in any of your
utilities? Didn't want to recreate the wheel ...

Peter Logan
Senior Database Administrator
Phone: 616/878-8309

From:
"Art Kagel" <art.kagel@gmail.com>
To:
ids@iiug.org
Date:
11/11/2009 10:34 PM
Subject:
Re: Application slow and data not saved [18065]
Sent by:
ids-bounces@iiug.org

OK, there are three metrics that give one a quick look at the health of a
server and suggest quick fixes. They are all calculated from the data in
the onstat -p output which you have fortunately supplied:

Bufwaits Ratio (BR): (bufwaits / (bufwrites + pagreads)) * 100.00 = 144.94

Buffer Turnover Rate (BTR): ((bufwrites + pagreads) / BUFFERS) / (hours
since stats) = 13.21
ReadAhead Utilization Ratio: (RA-pgsused / (ixda-RA + idx-RA + da-RA)) *
100.0 = 99.98

OK, interpretation:

BR indicates the percent of data accesses that are experiencing waits
while
attempting to access data pages in the cache. BR should be less than 7.0
ideally. Values between 7 and 10 indicate a server that's is occassionally

slow and some users may notice. If BR is above 10.00, and you have a BR of

144.9, and likely every process accessing the database is running slowly.
High BR can indicate that there are not enough buffers but more often it
indicates that there is contention for access to the LRU queues that
manage
the buffer cache and the number of LRUs have to be increased.

BTR indicates the number of times in an hour that the contents of the
entire
buffer cache is being replaced by other data pages.BTR should be in single

digits. Double digit values are indicative of excessive physical IO. High
BTR means you are churning the cache and need to increase BUFFERS. Your
current BTR value, 13.2, means you are turning over the entire buffer
cache
every 4.5 minutes (or churning a subset of the cache a lot more
frequently).

RAU indicates how effectively your IDS instance is using it read-ahead
pages. Excessive read-ahead can churn the buffer cache unnecessarily.
Ideally RAU should be as close to 100.0 as possible. Your value of 99.98
is
about as good as it gets.

So, what to do? Increase BUFFERS by doubling it from 8000 to at least
16000, though if you have the memory to spare I'd go higher, perhaps to
25000 or even 100000. I suggest this because your cache ratios are low.
The read cache hit rate of 78% is abysmal. For an OLTP system you should
be
getting a cache hit rate well overf 90%. Your write cahce hit rate of
89.6%
is just within the expected range, so it can improve also, though it's not

bad.

You currently have LRUS set to 8, I would increase this to the maximum
value
of 128. There is little cost to doing this and it will make a HUGE
difference in performance.

As to the ONCONFIG, I would change the following:

RESIDENT -1 # makes all of the engine's shared memory resident so it can't

swap out
AGING 1 # Prevents Solaris from degrading the oninit processes
priority over time
CLEANERS 128 # Keep set to the same as LRUS for best performance
LRUS 128
BUFFERS 25000
SINGLE_CPU_VP 1 # Your CPU is too slow for more than one CPU VP, so enable

this

optimization inside the engine so it can
reduce internal locking.

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 Tue, Nov 10, 2009 at 8:28 PM, MUMIN MARJUKI <mumin@akapost.com> wrote:

> Hi,
>
> I have IDS v7.30.UC7 running on Solaris 2.6 with 1024Mb RAM and 1 CPU
> 400Mhz .
> There is 2 application db at this IDS. The problem is application will
> running
> slow and sometime data cannot be saved when more user used this
> application.
> This application already running about 8 years and now it become slow..
>
> this is onstat -p output :
>
> Informix Dynamic Server Version 7.30.UC7 -- On-Line -- Up 2 days
00:14:22
> --
> 50688 Kbytes
>
> Profile
> dskreads pagreads bufreads %cached dskwrits pagwrits bufwrits %cached
> 30945890 4485340 140820758 78.02 63142 251189 609906 89.65
>
> isamtot open start read write rewrite delete commit rollbk
> 4122988 338018 649682 1248899 81844 10734 911 4852 918
>
> 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 39755.92 1429.96 529 1158
>
> bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans
> 7385086 711 3337555672 188 0 57 2095 42989
>
> ixda-RA idx-RA da-RA RA-pgsused lchwaits
> 145303 1137 29458137 29599384 0
>
> and this is my onconfig file :
>
> Informix Dynamic Server Version 7.30.UC7 -- On-Line -- Up 2 days
00:15:09
> --
> 50688 Kbytes
>
> Configuration File: /home1/informix/etc/onconfig.spplbp
>
#**************************************************************************

> #
> # INFORMIX SOFTWARE, INC.
> #
> # Title: onconfig.std
> # Description: INFORMIX-OnLine Configuration Parameters
> #
>
#**************************************************************************

>
> # Root Dbspace Configuration
>
> ROOTNAME rootdbs # Root dbspace name
> ROOTPATH /home1/dataspace/rootchunk
>
> # Path for device containing root dbspace
> ROOTOFFSET 1024 # Offset of root dbspace into device (Kbytes)
> ROOTSIZE 2000000 # 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 10000 # Physical log file size (Kbytes)
>
> # Logical Log Configuration
>
> LOGFILES 20 # Number of logical log files
> LOGSIZE 20000 # Logical log size (Kbytes)
>
> # Diagnostics
>
> MSGPATH /home1/informix/online.log # System message log file path
> CONSOLE /dev/console # System console message path
> ALARMPROGRAM /home1/informix/etc/no_log.sh # Alarm program path
>
> # System Archive Tape Device
>
> TAPEDEV /dev/rst4 # Tape device path
> TAPEBLK 16 # Tape block size (Kbytes)
> TAPESIZE 12000000 # Maximum amount of data to put on tape (Kbytes)
> #TAPESIZE 2097152 # Maximum amount of data to put on tape (Kbytes)
>
> # Log Archive Tape Device
>
> LTAPEDEV /dev/rst5 # Log tape device path
> LTAPEBLK 16 # Log tape block size (Kbytes)
> LTAPESIZE 12000000 # Max amount of data to put on log tape (Kbytes)
>
> # Optical
>
> STAGEBLOB # INFORMIX-OnLine/Optical staging area
>
> # System Configuration
>
> SERVERNUM 1 # Unique id corresponding to a OnLine instance
> DBSERVERNAME online_spplbp # Name of default database server
> DBSERVERALIASES # List of alternate dbservernames
> NETTYPE tlitcp,1,200,CPU # Override sqlhosts nettype parameters
> #NETTYPE ipcshm,1,200,CPU # Override sqlhosts nettype parameters
> DEADLOCK_TIMEOUT 60 # Max time to wait of lock in distributed env.
> RESIDENT 0 # Forced residency flag (Yes = 1, No = 0)
>
> MULTIPROCESSOR 0 # 0 for single-processor, 1 for multi-processor
> NUMCPUVPS 1 # 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 10000 # Maximum number of locks
> BUFFERS 8000 # Maximum number of shared buffers
> NUMAIOVPS 4 # Number of IO vps
> PHYSBUFF 128 # Physical log buffer size (Kbytes)
> LOGBUFF 64 # Logical log buffer size (Kbytes)
> LOGSMAX 40 # Maximum number of logical log files
> CLEANERS 4 # Number of buffer cleaner processes
> SHMBASE 0xa000000 # Shared memory base address
> SHMVIRTSIZE 8000 # initial virtual shared memory segment size
> SHMADD 8192 # Size of new shared memory segments (Kbytes)
> SHMTOTAL 0 # Total shared memory (Kbytes). 0=>unlimited
> CKPTINTVL 300 # Check point interval (in sec)
> LRUS 8 # Number of LRU queues
> LRU_MAX_DIRTY 60 # LRU percent dirty begin cleaning limit
> LRU_MIN_DIRTY 50 # 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 - 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 /home1/informix/dr.lostfound # DR lost+found file path
>
> # Read Ahead Variables
> RA_PAGES # Number of pages to attempt to read ahead
> RA_THRESHOLD # 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 tempchunk1 # 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 /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
>
> # ADT*
> # The following parameters control the type and level of secure auditing

> # present in the OnLine system. By default, ADTMODE is 0 and auditing
> # is disabled
>
> 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)
>
> # OFF => 0, LOW => 1, HIGH => 100
> 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
> # "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
>
> 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)
> SYSALARMPROGRAM /home1/informix/etc/evidence.sh # System Alarm program
path
> TBLSPACE_STATS 1
> CDR_LOGBUFFERS 2048 # size of log reading buffer pool (Kbytes)
> CDR_EVALTHREADS 1,1 # 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)
> BAR_ACT_LOG /tmp/bar_act.log
> BAR_MAX_BACKUP 4
> BAR_RETRY 1
> BAR_NB_XPORT_COUNT 10
> BAR_XFER_BUF_SIZE 31
> ISM_DATA_POOL ISMData # If the data pool name is changed, be sure to
> ISM_LOG_POOL ISMLogs
> HETERO_COMMIT 0
> OPT_GOAL -1
> DIRECTIVES 1
> RESTARTABLE_RESTORE off
>
> I think bufwaits little bit high at onstat -p.
> Does anything wrong with my onconfig file?
>
> thanks
>
>
>
>
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Messages In This Thread

• Application slow and data not saved
  MUMIN MARJUKI -- Tuesday, 10 November 2009, at 9:28 p.m.
  • Re: Application slow and data not saved
    Jonathan Leffler -- Tuesday, 10 November 2009, at 10:57 p.m.
    • Re: Application slow and data not saved
      James Horn -- Wednesday, 11 November 2009, at 9:55 a.m.
    • Re: Application slow and data not saved
      Jonathan Leffler -- Thursday, 12 November 2009, at 10:26 p.m.
  • RE: Application slow and data not saved
    Marcus Haarmann -- Wednesday, 11 November 2009, at 8:23 a.m.
  • Re: Application slow and data not saved
    Art Kagel -- Wednesday, 11 November 2009, at 10:33 p.m.
    • Re: Application slow and data not saved
      Peter_Logan@spartanstores.com -- Thursday, 12 November 2009, at 8:25 a.m.
      • Re: Application slow and data not saved
        Art Kagel -- Thursday, 12 November 2009, at 8:30 a.m.
        • Re: Application slow and data not saved
          Peter_Logan@spartanstores.com -- Thursday, 12 November 2009, at 8:37 a.m.
    • Re: Application slow and data not saved
      MUMIN MARJUKI -- Thursday, 12 November 2009, at 11:28 p.m.
      • Re: Application slow and data not saved
        MUMIN MARJUKI -- Friday, 13 November 2009, at 1:31 a.m.

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