Re: Query > 1000× slowdown after adding datetime comparison

And another thing which comes out as a little surprising to me - if I replace
the *date_last_updated* condition with another one, say *doc.documenttype =
4*, the query finishes immediately. *documenttype* is an unindexed integer
column.

Here's the query plan:

<http://postgresql.nabble.com/file/n5864080/qp3.png>

What's so special about that *date_last_updated* condition that makes it so
slow to use? Is it because it involves the *date()* function call that it
makes it difficult for the planner to guess the data distribution in the
DOCUMENT table?



--
View this message in context:
http://postgresql.nabble.com/Query-1-000-000-slowdown-after-adding-datetime-comparison-tp5864045p5864080.html
Sent from the PostgreSQL - performance mailing list archive at Nabble.com.