IDS Forum

RE: Update statistics performance

Posted By: Sebastian, Norma J.
Date: Thursday, 22 July 2004, at 7:52 a.m.

In Response To: Update statistics performance (Kenneth Makobe )

Ken,
Maybe perf tuning to deal with the 61 foreground writes (these are sqlexec user threads writing to disk, this is bad), the read cache % of 62.78% (kinda low), and the 3670835 seqscans (this might not be bad)....

Perf tuning those might help the perf of your update stats?


Fg Writes LRU Writes Chunk Writes
61 5808527 35281444

I'm not sure on this.... But maybe your LRU writes are too low in comparison to your chunk writes. Aren't chunk writes done during checkpoints (no prob there with that number), and LRU writes done during min/max dirty infx monitoring of the buffer cache? ... If so, perhaps getting more self-cleaning via LRU writes instead of letting the checkpoints do all the work might help.... BUT then you didn't say anything about checkpoint issues...

I could be way off base, but had to toss that in .... (I'm dealing with the nitty gritty perf issues on my system now so it catches my eye).

Norma Jean




-----Original Message-----
From: forum.subscriber@iiug.org [mailto:forum.subscriber@iiug.org] On Behalf Of Kenneth Makobe
Sent: Thursday, July 22, 2004 12:39 AM
To: ids@iiug.org
Subject: Update statistics performance [3275]

Hi all
Update Statistic takes a long duration of up to 13 hours to complete, our DB is more than 35 gb. I tried to use PDQ ,PSORT_NPROCS and DBSPACETEMP and the was only a slight improvement i.e from 13 to 12 hours. our IDS version is
17.31 uc5 Kindly advice on how this duration can be reduced Below is the profile and i/o queue stats and onstat -F profile

Profile
dskreads pagreads bufreads Êched dskwrits pagwrits bufwrits Êched
229690758 36261273 617122098 62.78 28229782 19567333 287833239 90.19

isamtot open start read write rewrite delete commit
rollbk
144865383 30923634 247207201 3231528422 186584701 26339127 233319 47761
4

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 529902.17 13244.00 1267 2534

bufwaits lokwaits lockreqs deadlks dltouts ckpwaits compress seqscans
30833338 50871 3330742991 0 0 4886 396427 3670835

ixda-RA idx-RA da-RA RA-pgsused lchwaits
6695267 15958151 175978636 198623320 15834291

AIO I/O queues:
q name/id len maxlen totalops dskread dskwrite dskcopy
kio 0 0 0 0 0 0 0
kio 1 0 16 57579748 52927126 4652622 0
kio 2 0 0 0 0 0 0
kio 3 0 16 108007501 96187935 11819566 0
kio 4 0 16 97292492 85534898 11757594 0
adt 0 0 0 0 0 0 0
msc 0 0 1 9313 0 0 0
aio 0 0 2 36214109 2 36213915 0
omstat -F


Fg Writes LRU Writes Chunk Writes
61 5808527 35281444

address flusher state data
60050500 0 I 0 = 0X0
600509ec 1 I 0 = 0X0
60050ed8 2 I 0 = 0X0
600513c4 3 I 0 = 0X0
600518b0 4 I 0 = 0X0
60051d9c 5 I 0 = 0X0
60052288 6 I 0 = 0X0
60052774 7 C 79 = 0X4f
60052c60 8 I 0 = 0X0
6005314c 9 I 0 = 0X0
60053638 10 I 0 = 0X0
60053b24 11 I 0 = 0X0
60054010 12 I 0 = 0X0
600544fc 13 I 0 = 0X0
600549e8 14 C 78 = 0X4e
60054ed4 15 I 0 = 0X0
states: Exit Idle Chunk Lru


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Messages In This Thread

• Update statistics performance
  Kenneth Makobe -- Thursday, 22 July 2004, at 1:39 a.m.
  • RE: Update statistics performance
    McCabe-Reed, Barbara SIK -- Thursday, 22 July 2004, at 5:17 a.m.
    • Re: RE: Update statistics performance
      CHUAN LU -- Saturday, 25 March 2006, at 3:20 a.m.
  • RE: Update statistics performance
    Sebastian, Norma J. -- Thursday, 22 July 2004, at 7:52 a.m.
    • RE: Update statistics performance
      Jonathan Leffler -- Thursday, 22 July 2004, at 8:37 p.m.
  • RE: Update statistics performance
    Kenneth Makobe -- Monday, 26 July 2004, at 2:52 a.m.

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