Re: performance penalty between Postgresql 8.3.8 and 8.4.1

On 8/12/2009 6:11 PM, Thom Brown wrote:

> Your output shows that the xdf_admin_hierarchy tables between versions
> are drastically different.  8.3.8 only contains 1 row, whereas 8.4.1
> contains 84211 rows.

That's just because one of them is doing a nested loop where it looks up
a single row from xdf_admin_hierarchy via its primary key on each
iteration. The other plan is doing a hash join on a sequential scan over
xdf_admin_hierarchy so it reports all the rows at once.

--
Craig Ringer