Hi!
Is it so that your test inserts, updates, and deletes
rows at random? Can these rows overlap? Do you have big
transactions?
If the above are true, you will inevitably get a lot
of deadlocks and rollbacks. Real-world applications
should be written in a way that deadlocks cannot occur,
or they are rare. One method is to access tables and rows
in a fixed order. In MyISAM you cannot get deadlocks
because there every SQL statement is a single transaction
and MyISAM locks all the tables involved in the statement
before starting the processing (this kind of all-at-once
locking is called 'conservative locking' in literature).
Regards,
Heikki
http://www.innodb.com
At 03:01 PM 7/10/01 +0300, you wrote:
>Content-Type: message/rfc822
>Content-Description: forwarded message
>Content-Transfer-Encoding: 7bit
>
>Subject: InnoDB behaviour with multiple clients
>From: Denis Pithon <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Date: 10 Jul 2001 10:51:40 +0200
>
>Hi all,
>
>I begin to validate MySQL with InnoDB on our platform. I use a DBI perl
>test which manages a data pool reflecting exactly the rows stored in DB.
>This test internally builds some new data to insert and chooses rows to
>delete and update (the tables are chosen randomly). Then all these
>operations are executed in one transaction. If it fails, a rollback is
>executed in DB and in client memory. Client also check that all data in
>its pool are in the DB. That's my test...
>
>It works very well with one client, but with two... things become
>harder! clients received many 'Table handler error 1000000' and slow
>down terrifically.
>
>I try the same test with 3 clients on MyISAM tables and there is no
>noticeable problems.
>
>I have reduced number of queries per transaction. I have changed
>innodb_unix_file_flush_method to O_DSYNC. I have increased buffer pool
>size and log buffer size but I noticed onlky small improvements. I'm
>sure I forgot something, but I don't see what ! does somebody know ??
>
>Denis
>
>--
>Denis Pithon phone +33 (0) 1 41 40 02 13
>Software Engineer fax +33 (0) 1 41 40 02 01
>Lineo High Availability Group mail [EMAIL PROTECTED]
>
>
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