Re: "explain analyse" much slower than actual query

[Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>]

"Phil Endecott" <spam_from_postgresql_general(at)chezphil(dot)org> writes:
> If I understand it correctly, it is still doing a sequential scan on 
> part_tsearch that does not terminate early due to the limit clause.  So 
> I'm still seeing run times that are rather worse than I think should be 
> possible.  Can it not step through the indexes in the way that it does 
> for a Merge Join until it has got enough results to satisfy the limit, 
> and then terminate?

Nope, there is not that much intelligence about NOT IN.

You could possibly manually rewrite the thing as a LEFT JOIN
with a WHERE inner-join-key IS NULL clause.  This would probably
lose if most of the outer relation's rows join to many inner rows,
though.

			regards, tom lane