> For example, if I have the following query: > Select * from a where x in (select y from b where z=7) > Then I would expect an index or hash structure to be created for b.y > when it is first scanned and brought into the cache but I couldn't see > it happening in the source. > As I said, I only inferred it from reading the source - not from actual > experiments - so I may be wrong. > 1. Am I wrong?
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You are wrong - this is old behaviour and one of the major speed improvements of PostgreSQL 7.4 is that IN subqueries now use a hash index and hence they are much faster. Chris ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
