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Neil Truby found ALTER FRAGMENT INIT and index rebuilds 20-40% slower on IDS 9.40 FC1/FC2 than on 9.21 FC4 on HP-UX 11.11, with the same ONCONFIG and kaio. John Carlson suggested PDQ for index builds. Rich Campbell saw the same on Solaris; support told him the engine wrote empty pages to the physical log during index builds, a fix was slated, and onstat -D would confirm it.
Auto-generated by Claude from the posts below — may be imperfect; read the full thread.
Neil Truby — — source: Usenet: comp.databases.informix
HP-UX 11.11
I'm doing some benchmark testing on a critical process to our client - alter
fragment init ... in dbspace of medium and large tables. In every case,
9.40 (I'm trying both FC1 and FC2) is substantially (that is 20-40%)
*slower* than the equivanlent statement on 9.21 FC4.
I have kaio enabled in all the tests, and am using the same $ONCONFIG file
for each, so the test ought to be pretty representative of the IDS versions'
performance under HP-UX 11.11. Actually, I disabled kaio for one test and
it made no difference.
Has anyone else had a similar, or contrary, experience with IDS v9.40?
thanks
Neil
↪ replying to Neil Truby
Neil Truby — — source: Usenet: comp.databases.informix
I have refined the testing further, and broken the alter fragment into its
component parts:
1. an alter fragment with no indexes
2. a re-build of the indexes
In both cases 9.40 is markedly slower than 9.21, on the same hardware,
chunks and ONCONFIG parms.
"Neil Truby" <neil.truby@ardenta.com> wrote in message
news:bqg8jn$21e6lv$1@ID-162943.news.uni-berlin.de...
> HP-UX 11.11
>
> I'm doing some benchmark testing on a critical process to our client -
alter
> fragment init ... in dbspace of medium and large tables. In every case,
> 9.40 (I'm trying both FC1 and FC2) is substantially (that is 20-40%)
> *slower* than the equivanlent statement on 9.21 FC4.
>
> I have kaio enabled in all the tests, and am using the same $ONCONFIG file
> for each, so the test ought to be pretty representative of the IDS
versions'
> performance under HP-UX 11.11. Actually, I disabled kaio for one test and
> it made no difference.
>
> Has anyone else had a similar, or contrary, experience with IDS v9.40?
>
> thanks
> Neil
>
>
↪ replying to Neil Truby
John Carlson — — source: Usenet: comp.databases.informix
On Tue, 2 Dec 2003 13:08:40 -0000, "Neil Truby"
<neil.truby@ardenta.com> wrote:
>I have refined the testing further, and broken the alter fragment into its
>component parts:
>
>1. an alter fragment with no indexes
>2. a re-build of the indexes
>
>In both cases 9.40 is markedly slower than 9.21, on the same hardware,
>chunks and ONCONFIG parms.
>
>
One of the things I've noticed from 9.21 is that detached index builds
are much slower than attached index builds (or semi-detached index, to
be technical). I've used PDQ for index builds (as part of a reorg)
and that seems to speed things up a bit...
Can't speak as to 1), though...
Neil,
I see the same.
We are using 9.40 FC2 for Solaris 2.8.
A bug has been opened for my case:
Index builds taking 50-300 % longer then in 7.31 regardless of amount of PDQ
resources allocated. Slowness shows up with larger tables. In our case
150-800 mill rows.
Support says that the engine is erroneously writing empty pages to the
physical log when building the index. A fix is slated.
onstat -D will confirm this behavior for 9.40 FC. You will not see this in
7.31.
I also see slowness (~50 %) with onpload for large tables with same symptom.
Rich
"Neil Truby" <neil.truby@ardenta.com> wrote in message
news:bqg8jn$21e6lv$1@ID-162943.news.uni-berlin.de...
> HP-UX 11.11
>
> I'm doing some benchmark testing on a critical process to our client -
alter
> fragment init ... in dbspace of medium and large tables. In every case,
> 9.40 (I'm trying both FC1 and FC2) is substantially (that is 20-40%)
> *slower* than the equivanlent statement on 9.21 FC4.
>
> I have kaio enabled in all the tests, and am using the same $ONCONFIG file
> for each, so the test ought to be pretty representative of the IDS
versions'
> performance under HP-UX 11.11. Actually, I disabled kaio for one test and
> it made no difference.
>
> Has anyone else had a similar, or contrary, experience with IDS v9.40?
>
> thanks
> Neil
>
>
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