From: John Scalia <jayknowsunix@gmail.com>
To: pgsql-admin@postgresql.org
Subject: Index not always being used
Date: Thu, 29 Aug 2019 10:15:28 -0400
Message-ID: <180F96D3-690E-466E-B73E-F6B34C6409C7@gmail.com> (raw)
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 table scan is going to be used, but if I change the query to use “where bold_city like ‘basking%’”, then explain correctly shows that a bitmap index scan will be performed. Why would these two forms use different approaches? I’m a bit confused.
—
Jay
Sent from my iPad
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: jayknowsunix@gmail.com
Subject: Re: Index not always being used
In-Reply-To: <180F96D3-690E-466E-B73E-F6B34C6409C7@gmail.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox