Doug Mitchell (pgsql@dougmitchell.com) reports a bug with a severity of 3
The lower the number the more severe it is.
Short Description
Backend touches index not involved in update / NULL indexing
Long Description
I had some updates that were taking a few seconds each on a primary-keyed table with a few million records. I dropped
anindex on a field not involved in the query and the updates now run several times faster.
Idea: The non-involved field which was indexed with a btree has a lot of NULLs in it. The btree node with the NULLs
(severalmillion records) had to be processed thus slowing performance. Please provide and document a way to turn
on/offthe indexing of NULL values.
Either way, PG should not have to update the index in the first place,
because it indexes a field which is not part of the SET or WHERE in the UPDATE statement.
Thanks,
Doug
Sample Code
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