Re: rows estimate in explain analyze for the BRIN index - Mailing list pgsql-hackers

From Emre Hasegeli
Subject Re: rows estimate in explain analyze for the BRIN index
Date
Msg-id CAE2gYzwT0uEWitsOBBM4cM9cx_f8GBxPdH47YapCtGHyn0APSQ@mail.gmail.com
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In response to Re: rows estimate in explain analyze for the BRIN index  (Oleksii Kliukin <alexk@hintbits.com>)
Responses Re: rows estimate in explain analyze for the BRIN index  (Tom Lane <tgl@sss.pgh.pa.us>)
Re: rows estimate in explain analyze for the BRIN index  (Oleksii Kliukin <alexk@hintbits.com>)
List pgsql-hackers
> which is much closer to the actual number of rows removed by the index
> recheck + the one left.

Is it better to be closer?  We are saying those are the "actual"
values not the estimates.  If we cannot provide the actual rows, I
think it is better to provide nothing.  Something closer to the
reality would create more confusion.  Maybe, we just just return the
number of blocks, and put somewhere a note about it.  The actual row
count is already available on the upper part of the plan.

By the way, the estimation is a bigger problem than that.  Please see
my patch [1] about it.

[1] http://www.postgresql.org/message-id/CAE2gYzzJvzPy-1cSgZjJyH69izSa13SEgFC4i4r2z0qBQ2P8Uw@mail.gmail.com



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