Skip site navigation (1) Skip section navigation (2)

Re: Planner question - "bit" data types

From: Josh Berkus <josh(at)agliodbs(dot)com>
To: Karl Denninger <karl(at)denninger(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Planner question - "bit" data types
Date: 2009-09-04 22:29:59
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance

> For reference, I was having SEVERE performance problems with the
> following comparison in an SQL statement where "mask" was an integer:
> "select ... from .... where ...... and (permission & mask = permission)"

AFAIK, the only way to use an index on these queries is through
expression indexes.  That's why a lot of folks use INTARRAY instead; it
comes with a GIN index type.

It would probably be possible to create a new index type using GiST or
GIN which indexed bitstrings automatically, but I don't know that anyone
has done it yet.

Changing your integer to a bitstring will not, to my knowledge, improve

Josh Berkus
PostgreSQL Experts Inc.

In response to


pgsql-performance by date

Next:From: Merlin MoncureDate: 2009-09-05 20:09:07
Subject: Re: Planner question - "bit" data types
Previous:From: Kevin GrittnerDate: 2009-09-04 22:09:37
Subject: Re: Seeking performance advice and explanation for high I/O on 8.3

Privacy Policy | About PostgreSQL
Copyright © 1996-2017 The PostgreSQL Global Development Group