From: | Andreas Kretschmer <andreas(at)a-kretschmer(dot)de> |
---|---|
To: | pgsql-general(at)lists(dot)postgresql(dot)org |
Subject: | Re: Multicolumn index for single-column queries? |
Date: | 2019-04-18 07:14:47 |
Message-ID: | af88e7c8-8274-70f6-e1c7-e3e59e6bf6c7@a-kretschmer.de |
Views: | Whole Thread | Raw Message | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
Am 18.04.19 um 08:52 schrieb rihad:
> Hi. Say there are 2 indexes:
>
> "foo_index" btree (foo_id)
>
> "multi_index" btree (foo_id, approved, expires_at)
>
>
> foo_id is an integer. Some queries involve all three columns in their
> WHERE clauses, some involve only foo_id.
> Would it be ok from general performance standpoint to remove foo_index
> and rely only on multi_index? I know that
> PG would have to do less work updating just one index compared to
> updating them both, but wouldn't searches
> on foo_id alone become slower?
it depends .
it depends on the queries you are using, on your workload. a
multi-column-index will be large than an index over just one column,
therefore you will have more disk-io when you read from such an index.
Regards, Andreas
--
2ndQuadrant - The PostgreSQL Support Company.
www.2ndQuadrant.com
From | Date | Subject | |
---|---|---|---|
Next Message | Laurenz Albe | 2019-04-18 08:40:16 | Re: Multicolumn index for single-column queries? |
Previous Message | Gavin Flower | 2019-04-18 07:14:13 | Re: Multicolumn index for single-column queries? |