From: Claudio Nanni
Date: February 19 2009 7:14pm
Subject: InnoDB - CREATE INDEX - Locks table for too long
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I need to add an index on a table on a production server.
It is one 7Gb InnoDB table with single .ibd file (one_file_per_table),
the index creation on preprod server took 40 minutes but table was smaller.
I tried to add the index but was locking all applications on production 
and had to kill it.
I have requested a maintenance window but it will take long time.
Since this application is scanning like crazy I'd like to do it a.s.a.p.

Do you have any hint for a non locking solution?

I have created smaller indexes and brought the average rows retrieved 
via full table scan from 2 Million to 400.000 per second, now I just 
need this last index!
Thanks to Baron for the slow-query-log analyzer tool, it is simple but 
perfect!
And I used it without patching the server.
I have easily found the worst queries just watching three values: 
elapsed time, number of occurences, and rows retrieved.
And I discovered all the tables which needed indexing, so simple, so 
good! Thanks Baron!

Cheers

Claudio