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From:Michael Widenius Date:September 8 1999 12:33pm
Subject:-- Why can this cause mysqld to crash?
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>>>>> "Mark" == Mark Papadakis <markp@stripped> writes:

Mark> Hi!
Mark> After checking the host.log file, it seems like mysql crashes on the following
> query... ( snippet follows )
Mark> Any ideas why this can happen? Should I lock any tables just to make sure?

Mark>                     654 Connect    nobody@localhost on
Mark>                     654 Init DB    ads
Mark>                     654 Query      select * from ads where id=18
Mark>                     654 Query      update dstats set impressions=impressions+1
> where banner_id=18 and dt=19990807
Mark>                     654 Quit


Is impressions a part of an index?  If yes, then remove it!  The
problem is that MySQL 3.22 have a problem when updating an index to a
value that will be found later while scanning the index tree!

MySQL 3.23 solves this (when you update an index) by first scanning
for all matching rows and then updating the found rows.

-- Why can this cause mysqld to crash?Mark Papadakis7 Sep
  • -- Why can this cause mysqld to crash?Jani Tolonen8 Sep
  • -- Why can this cause mysqld to crash?Michael Widenius8 Sep