Re: Bug 712, 914..... and now 1027

Hi!

On Aug 12, [email protected] wrote:
> 
> Alexander Keremidarski indicated that he can not repeat the issue bought to
> light by Paul's test case (bug #1027), yet he has not once attempted to run
> the test case on RedHat 7.3 (nor even on MySQL 4.0.14) which the bug report
> calls for as he considers testing performance issues between RedHat releases
> to be 'irrelevant'.

You are missing the point here.
I was able to reproduce Paul's timings on my home FreeBSD-4.7 - 
same box - running 4.0.14 - same binary - with
innodb_flush_log_at_trx_commit=0 and innodb_flush_log_at_trx_commit=1.

As Salle noted innodb_flush_log_at_trx_commit=0 is default settings
before MySQL 4.0.13. Since 4.0.13 it's innodb_flush_log_at_trx_commit=1.

> Irrelevant to whom I may ask?  Certainly not irrelevant to those of us
> enjoying current performance on RH 7.3 who have now chosen to upgrade to RH
> 9.0.  I would not consider an upgrade from MySQL 3.23.49, RedHat 7.3 to
> MySQL 4.0.14, RedHat 9.0 an unusual case, nor one where you would expect to
> get your fingers burned yet I have run the test case provided by Paul and
> quite easily reproduced the poor performance he has uncovered.

Irrelevant in this particular case - sorry it must be language
problems, English is not my mother tongue, that's why I, probably,
understand Salle better sometimes - means that you cannot base
any judgements on this. There are results from two different
hardware configurations, different my.cnf settings, different MySQL
versions and different RedHat versions.

Any factor from the above can affect the results.
According to my tests (as above) I suppose it was different default
settings for innodb_flush_log_at_trx_commit.

> Using identical hardware (previously a master/slave backup system) I ran
> BOTH test cases provided by Paul Coldrey on MySQL 3.23.49, RedHat 7.3 and
> MySQL 4.0.14, RedHat 9.0 and can verify that I received similar poor
> performance easily and repetedly.

Can you please confirm that your test results were NOT affected by
innodb_flush_log_at_trx_commit settings ? (may be you had this variable
set in your my.cnf ?)

Regards,
Sergei

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 / /|_/ / // /\ \/ /_/ / /__  MySQL AB, Senior Software Developer
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