IDS Forum

RE: long checkpoints

Posted By: Darrell Murphy
Date: Thursday, 28 October 2004, at 2:46 p.m.

In Response To: RE: long checkpoints (Alexey Sonkin )

Is there any chance you can increase CLEANERS and LRUS? I know this is =
a
memory balancing issue but if you can, try to increase those. When we =
get a
long checkpoint it is often because the LRUS and CLEANERS got swamped =
with
data and can't keep up.

Darrell Murphy
Burton Snowboards


-----Original Message-----
From: Alexey Sonkin [mailto:alexeis@grandvirtual.com]
Sent: Thursday, October 28, 2004 1:29 PM
To: ids@iiug.org
Subject: RE: long checkpoints [3587]=20


Karen,

What platform are you on? Is it supporting KAIO?
(take a look at onstat -g iov)

It seems, you need to increase NUMAIOVPS to smth reasonable
(like: number of physical disk drives)=20

Is there any reason for setting " NOFUZZYCKPT 1"?

If is very useful to take a look at onstat -R before
the checkpoint and at onstat -F

-Alexey
=20

> -----Original Message-----
> From: Egan Karen-.... [mailto:Karen.Egan@motorola.com]
>=20
> Hi all,
>=20
> the performance on one of our Customer's production databases has
decreased
> dramatically in the last couple of weeks. Checkpoints seem to be =
taking
over a
> minute to complete. Running IDS 9.21 UC6 (which I know is no longer
supported
> but unfortunately as it is out there in our product in the field I =
can't
do
> much about this) on Solaris 8.
>=20
> If anyone has any pointers on the config parameters below that may =
help to
> improve performance they would be greatly appreciated. Also are there =
any
know
> bugs with checkpoints on this version of Informix.
>=20
> Below are what I believe are the relevant onconfig parameters
>=20
> PHYSDBS omc_db_plog # Location (dbspace) of physical log
> PHYSFILE 253894 # Physical log file size (Kbytes)
>=20
> LOGFILES 3 # Number of logical log files
> LOGSIZE 2000 # Logical log size (Kbytes)
>=20
> NOFUZZYCKPT 1 # No fuzzy checkpoints
>=20
>=20
> 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
>=20
>=20
> # Shared Memory Parameters
> LOCKS 75000 # Maximum number of locks
> BUFFERS 50000 # Maximum number of shared buffers
> NUMAIOVPS 1 # Number of IO vps
> PHYSBUFF 128 # Physical log buffer size (Kbytes)
> LOGBUFF 128 # Logical log buffer size (Kbytes)
> LOGSMAX 50 # Maximum number of logical log files
> CLEANERS 6 # Number of buffer cleaner processes
> SHMBASE 0xa000000 # Shared memory base address
> SHMVIRTSIZE 32000 # initial virtual shared memory =
segment
size
> SHMADD 8192 # Size of new shared memory segments
(Kbytes)
> SHMTOTAL 0 # Total shared memory (Kbytes).
0=3D>unlimited
> CKPTINTVL 300 # Check point interval (in sec)
> LRUS 15 # 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 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)
> RA_PAGES 32 # Number of pages to attempt to read =
ahead
> RA_THRESHOLD 28 # Number of pages left before next =
group
> DBSPACETEMP omc_db_temp # Default temp dbspaces
>=20
> output from onstat -p
>=20
> Profile
> dskreads pagreads bufreads =CAched dskwrits pagwrits bufwrits =CAched
> 890960 1087371 36156569 97.54 851638 1850908 3389826 74.88
>=20
> isamtot open start read write rewrite delete commit
rollbk
> 27502723 47701 2493635 17606895 857421 17010 300250 823 =
0
>=20
> gp_read gp_write gp_rewrt gp_del gp_alloc gp_free gp_curs
> 0 0 0 0 0 0 0
>=20
> ovlock ovuserthread ovbuff usercpu syscpu numckpts flushes
> 0 0 0 2598.48 409.81 84 196
>=20
> bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress =
seqscans
> 164589 93 18694337 0 0 88 42716 5906
>=20
> ixda-RA idx-RA da-RA RA-pgsused lchwaits
> 271575 11542 14060 292760 6173
>=20
> onstat -m
>=20
> Informix Dynamic Server 2000 Version 9.21.UC6 -- On-Line -- Up
08:16:55 --
> 147456 Kbytes
>=20
> Message Log File: /usr/informix/online.log_OMC
> <<Informix Dynamic Server 2000>>> Logical Log 12764 Complete.
> 01:50:59 Logical Log 12764 Complete.
> 01:53:23 Checkpoint Completed: duration was 97 seconds.
> 01:53:23 Checkpoint loguniq 12765, logpos 0x2af3d4
>=20
> 01:59:59 Checkpoint Completed: duration was 95 seconds.
> 01:59:59 Checkpoint loguniq 12765, logpos 0x14df54c
>=20
> 02:06:04 Checkpoint Completed: duration was 66 seconds.
> 02:06:04 Checkpoint loguniq 12765, logpos 0x2595418
>=20
>=20
> <<Informix Dynamic Server 2000>>> Logical Log 12765 Complete.
> 02:10:10 Logical Log 12765 Complete.
> 02:12:06 Checkpoint Completed: duration was 62 seconds.
> 02:12:06 Checkpoint loguniq 12766, logpos 0x3bc418
>=20
> 02:18:16 Checkpoint Completed: duration was 70 seconds.
> 02:18:16 Checkpoint loguniq 12766, logpos 0x1676018
>=20

Messages In This Thread

• long checkpoints
  Egan Karen-kegan01 -- Tuesday, 28 September 2004, at 9:49 a.m.
  • Re: long checkpoints
    jspalla@anexsys.com -- Tuesday, 28 September 2004, at 12:10 p.m.
  • RE: long checkpoints
    Alexey Sonkin -- Thursday, 28 October 2004, at 1:28 p.m.
    • RE: long checkpoints
      Darrell Murphy -- Thursday, 28 October 2004, at 2:46 p.m.
      • RE: long checkpoints
        Esteban Casuscelli -- Thursday, 28 October 2004, at 6:13 p.m.

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