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Re: Optimize query for listing un-read messages - Mailing list pgsql-performance

From Pavel Stehule
Subject Re: Optimize query for listing un-read messages
Date
Msg-id CAFj8pRAOrokrj9JDG=u6uqxOfb26EsbN6zhuRq9zPQeSQ4k-og@mail.gmail.com
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In response to Re: Optimize query for listing un-read messages  (Andreas Joseph Krogh <andreas@visena.com>)
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2014-05-01 21:39 GMT+02:00 Andreas Joseph Krogh <andreas@visena.com>:
På torsdag 01. mai 2014 kl. 21:30:39, skrev Pavel Stehule <pavel.stehule@gmail.com>:
Hello
[snip]
 
I had a perfect success on similar use case with descent ordered partial index

http://www.postgresql.org/docs/9.3/interactive/sql-createindex.html
 
I'm not getting good performance. Are you able to craft an example using my schema and partial index?

maybe some like

CREATE INDEX ON message_property (person_id, message_id) WHERE pr.is_read

When I am thinking about your schema, it is designed well, but it is not index friendly, so for some fast access you should to hold a cache (table) of unread messages.

Regards

Pavel
 
 
Thanks.
 
--
Andreas Jospeh Krogh
CTO / Partner - Visena AS
 

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