Tickets :: Comment on [#12476] Database running mad after update to 5.1.1

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Comment	> I think what's happening with the MAX query is that the index is in > ASC order and the order of the columns in the composite index is in > the wrong order. Creating the composite index on object_uid, > history_modseq (instead of history_modseq, object_uid) reduces the > number of rows to scan for me by multiple orders of magnitude. > > ORDER BY/LIMIT query also seems to greatly improve performance as > shown by EXPLAIN on my production server. My development server uses > the less efficient filesort but I'm thinking that's because the > number of rows is much smaller. > > >
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