From: isayko.alexey@gmail.com
To: pgsql-bugs@postgresql.org
Subject: BUG #14563: count(*) gives a wrong result in PostgreSQL for some regex with pg_trm/GIN index
Date: Wed, 22 Feb 2017 11:14:46 +0000
Message-ID: <20170222111446.1256.67547@wrigleys.postgresql.org> (raw)
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The following bug has been logged on the website:
Bug reference: 14563
Logged by: Alexey Isayko
Email address: isayko.alexey@gmail.com
PostgreSQL version: 9.6.1
Operating system: Windows 10.0.14393 x64
Description:
When using some RE to filter rows on gin-indexed column with pg_trm,
count(*) could give a wrong result (zero instead of real count):
CREATE EXTENSION pg_trgm;
CREATE TABLE t (
s text
);
CREATE INDEX ON t USING gin (s gin_trgm_ops);
INSERT INTO t VALUES ('12-34');
SET enable_seqscan = OFF; -- to force using the index on our small table
SELECT count(*) FROM t WHERE s~'\d{2}[-]?\d{2}'; -- gives me 0 and it's
wrong
But if we will turn on seq scans, we will get the correct result:
SET enable_seqscan = ON;
SELECT count(*) FROM t WHERE s~'\d{2}[-]?\d{2}'; -- gives me 1 and it's
correct
Same behaviour I get with 9.5.4 (windows and linux) and 9.6.1 (windows)
versions of the PostgreSQL
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To: pgsql-bugs@postgresql.org
Cc: isayko.alexey@gmail.com
Subject: Re: BUG #14563: count(*) gives a wrong result in PostgreSQL for some regex with pg_trm/GIN index
In-Reply-To: <20170222111446.1256.67547@wrigleys.postgresql.org>
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