| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Oleksii Kliukin <alexk(at)hintbits(dot)com> |
| Cc: | Álvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: rows estimate in explain analyze for the BRIN index |
| Date: | 2015-12-30 16:44:07 |
| Message-ID: | 15870.1451493847@sss.pgh.pa.us |
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| Lists: | pgsql-hackers |
Oleksii Kliukin <alexk(at)hintbits(dot)com> writes:
>> On 30 Dec 2015, at 17:02, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> Another idea would be to use the heap's row density as calculated
>> by the last ANALYZE (ie, reltuples/relpages), with a fallback to 100
>> if relpages=0. This'd only be convenient if the bitmap scan node has
>> the parent heap rel open, which it might not.
> +1
Any objections to the attached?
regards, tom lane
| Attachment | Content-Type | Size |
|---|---|---|
| brin-better-tuple-estimate.patch | text/x-diff | 2.4 KB |
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