Re: random_page_cost vs seq_page_cost - Mailing list pgsql-hackers

From Robert Haas
Subject Re: random_page_cost vs seq_page_cost
Date
Msg-id CA+TgmoY4DBtqTX+ee8CMA55aoY169EX2wdXRSAv6twvdwg4TxQ@mail.gmail.com
Whole thread Raw
In response to random_page_cost vs seq_page_cost  (Benedikt Grundmann <bgrundmann@janestreet.com>)
List pgsql-hackers
On Thu, Jan 5, 2012 at 5:04 AM, Benedikt Grundmann
<bgrundmann@janestreet.com> wrote:
> We are experiencing a big performance regression in some queries.
> In those cases the planner seems to choose a nested loop index
> scan instead of hashing the index once and then joining.

I think you probably need to post EXPLAIN ANALYZE output from the
actual queries to get useful advice, probably to pgsql-performance,
rather than here.

It's hard to believe that enable_nestloop=off is doing anything other
than masking whatever the real problem is, but it's hard to tell what
that problem is based on the information provided.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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