Some thoughts :

1. Is it possible to build an index on the columns that comprise the group by ? make it a Hash one since you work on exact equality matches, thus the delete will operate a lot faster.

2. Try using NOT EXISTS (although they are not the same semantically, but in most cases they do match)

3. Having a function, DATE_TRUNC, inside the group by slows the query a lot. Turn on the query optimizer to check if that it is true.

In reply to Re: Help on selecting and deleting many records in a DB. by nikosv
in thread Help on selecting and deleting many records in a DB. by neilwatson

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