| From: | "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com> |
|---|---|
| To: | Sbob <sbob(at)quadratum-braccas(dot)com> |
| Cc: | Rui DeSousa <rui(dot)desousa(at)icloud(dot)com>, "pgsql-performance(at)lists(dot)postgresql(dot)org" <pgsql-admin(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: checking for a NULL date in a partitioned table kills performance |
| Date: | 2024-08-23 00:01:37 |
| Message-ID: | CAKFQuwZKTiS5b_Loe21p9rFBzR5XriHODPeocP40QAECTHEMkA@mail.gmail.com |
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| Lists: | pgsql-admin pgsql-performance |
On Thu, Aug 22, 2024 at 4:32 PM Sbob <sbob(at)quadratum-braccas(dot)com> wrote:
>
> 29 million of the 32 million rows in the table have NULL for contract_date
>
>
Your expectation that this query should use an index is flawed. Indexes
are for highly selective queries. Finding nulls on that table is not
selective.
David J.
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