Re: BUG #15609: synchronous_commit=off insert performance regression with secondary indexes

Thank you, yes that makes sense.
We only use partial Boolean indexes on large tables
or normal Boolean indexes on small (0-10M rows) queue tables that get
cleared down.

On Tue, 5 Feb 2019 at 12:08, Bruce Momjian <bruce(at)momjian(dot)us> wrote:

> On Fri, Feb 1, 2019 at 10:49:13AM +1300, Saul, Jean Paolo wrote:
> > Hi Bruce,
> >
> > Thank you for that info. We will likely migrate our boolean indexes (and
> > possibly all our low cardinality indexes) to hash after we move to PG11.
>
> Uh, there is rarely value in creating boolean indexes because, for an
> index to be useful, it should have high selectivity. What people often
> do is to create _partial_ indexes on true, false, or NULL values that
> are of high selectivity. Since there is only a single value in the
> index, I guess a hash index would be better than btree, but I am not
> sure.
>
> --
> Bruce Momjian <bruce(at)momjian(dot)us>
> https://urldefense.proofpoint.com/v2/url?u=http-3A__momjian.us&d=DwIBAg&c=MPZC0Rv-kl4oeK4li6Jc92hnsiCC4tOZO_GSKscRWJE&r=VrrIZRoLr_yZJ3k_V9FTyEmoRy2AmFzy-R0X02P-nWQ&m=A8B3Bqt35dF1w-Myg_aaGo60wWI-OYNQRVwNYoe7REo&s=4Et9835fubwbTEUhqaEGIF57CiiUPdgbFEMZpPA_5Zw&e=
> EnterpriseDB
> https://urldefense.proofpoint.com/v2/url?u=http-3A__enterprisedb.com&d=DwIBAg&c=MPZC0Rv-kl4oeK4li6Jc92hnsiCC4tOZO_GSKscRWJE&r=VrrIZRoLr_yZJ3k_V9FTyEmoRy2AmFzy-R0X02P-nWQ&m=A8B3Bqt35dF1w-Myg_aaGo60wWI-OYNQRVwNYoe7REo&s=3JAKbpzBP8EeAuCgkGz6GWh3JrU85rCssCHpQV85FV8&e=
>
> + As you are, so once was I. As I am, so you will be. +
> + Ancient Roman grave inscription +
>

--------------------------------------------------------------------------------------------------------------------------------------------
PLEASE CONSIDER THE ENVIRONMENT BEFORE PRINTING THIS EMAIL

VERIZON CONNECT CONFIDENTIALITY NOTICE
This message is intended for the addressee only and may contain confidential and/or privileged material. Any review, re-transmission, dissemination, reliance upon or other use of this information by persons or entities other than the addressee is prohibited. If you receive this in error, please contact the sender and delete this message. Thank you.