Unintentional Googlewhack Leads to MySQL Bug Report

Posted in: MySQL, Technical Track

While doing a standard audit for a new client, I recommended a few changes to get better performance. Because I had several changes, I used the documentation at


and found that innodb_flush_log_at_trx_commit is a dynamic variable. I was surprised, because most operations dealing with file sizes and operations are not dynamic. But the client proceeded with:

set global innodb_flush_log_at_trx_commit = 2;

and got:

ERROR 1193 (HY000): Unknown system variable 'innodb_flush_log_at_trx_commit'

So I searched for others who may have had the same error, and ended up getting an unintentional googlewhack. Well, it’s not a real Googlewhack, because it has more than 2 words and I used quotes to surround it — but I was pretty surprised that there were not a lot more people like me who trusted the manual. Granted, it’s “intuitive” that the variable is one that would need a restart….but because I was looking up others, I just looked up all of them, and thus fell into the trap.

The search I did was “Unknown system variable innodb_flush_log_at_trx_commit”

And the bug I filed is http://bugs.mysql.com/bug.php?id=35575.

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3 Comments. Leave new

Actually it is a dynamic variable, at least in later versions of 5.0.x — I use this whenever I reboot a server that is running on 2, dynamically set to 1 before the reboot to prevent data loss.

Verified on 5.0.45 and 5.0.46

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December 10, 2008 8:17 am

[…] Unintentional Googlewhack Leads to MySQL Bug Report […]


This post saved my life! I just *knew* I was going to restart my database to make this change, because nothing I could find in the docs say this can be done on the fly. Thanks for the post!


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