Index not always being used - Mailing list pgsql-admin

From John Scalia
Subject Index not always being used
Date
Msg-id 180F96D3-690E-466E-B73E-F6B34C6409C7@gmail.com
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Responses Re: Index not always being used
Re: Index not always being used
List pgsql-admin
I’ve got a table with approximately 5.5 million rows, and one column that is frequently searched is of type varchar(50)
and we just put a trigram index on it. Now, if we search “where bld_city = ‘baskingridge’”, explain says a sequential
tablescan is going to be used, but if I change the query to use “where bold_city like ‘basking%’”, then explain
correctlyshows that a bitmap index scan will be performed. Why would these two forms use different approaches? I’m a
bitconfused. 
—
Jay

Sent from my iPad


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