Re: Much slower DBI on RHEL6

in reply to Much slower DBI on RHEL6

Well, just to commiserate, not that long ago I migrated an application from a CentOS 5 server to a CentOS 6 server. The CentOS 6 server was faster hardware by every measure, and you could feel it.

But my MySQL table data load times (insert statements through Perl DBI) nearly tripled. Spent too much time searching for a cause and solution without success. Despite the stupid slow load times, the application itself 'did' run faster overall for day to day use (or at least fast enough) and I left it at that. Probably an averaging out of code execution vs query execution

There 'is' something wrong with the Perl/DBI/MySQL performance in CentOS 6. I continue with the assumption that somebody will eventually find the reason and a patch will fix it. In the mean time I accept that the table loads will be slower (a not too often initialization step) and the daily operation is fast enough.

Comment on Re: Much slower DBI on RHEL6

Replies are listed 'Best First'.
Re^2: Much slower DBI on RHEL6 by graff (Chancellor) on Feb 08, 2014 at 05:28 UTC
How are you handling commits? I think "autocommit" is turned on by default (commit after every execution of an insert or update), and that can be outrageously slow when slogging through a long list. I wrote a general-purpose command-line tool for doing inserts/updates using data from stdin or a file, and the best thing about it is the option that lets me set the commit interval. If I forget to use that option on an input of many thousands of rows, I really regret it, but when I set it to commit every 500 or 1000 rows, it flies, and I love it.	[reply]

Replies are listed 'Best First'.

Re^2: Much slower DBI on RHEL6
by graff (Chancellor) on Feb 08, 2014 at 05:28 UTC

I wrote a general-purpose command-line tool for doing inserts/updates using data from stdin or a file, and the best thing about it is the option that lets me set the commit interval. If I forget to use that option on an input of many thousands of rows, I really regret it, but when I set it to commit every 500 or 1000 rows, it flies, and I love it.

[reply]

In Section Seekers of Perl Wisdom