Re: WHERE with ORDER not using the best index

From: jugnooken <ken(at)jugnoo(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: WHERE with ORDER not using the best index
Date: 2014-01-30 01:47:19
Message-ID: 1391046439075-5789624.post@n5.nabble.com
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Thank you so much for the prompt reply, Tom. The index is actually fairly new
- but to be safe I issued REINDEX TABLE so that they are all clean. Here are
the sizes of each index right after REINDEX.

db=> select
pg_size_pretty(pg_relation_size('index_social_feed_feed_items_on_social_feed_id_and_posted_at'));
pg_size_pretty
----------------
149 MB
(1 row)

db=> select
pg_size_pretty(pg_relation_size('index_social_feed_feed_items_on_social_feed_id'));
pg_size_pretty
----------------
106 MB
(1 row)

Unfortunately, pg still thinks using
index_social_feed_feed_items_on_social_feed_id is faster although they are
about the same size :(. Any idea?

Regards,
Ken

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