Re: explain analyze rows=%.0f
Tom Lane <tgl@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Simon Riggs <simon@2ndQuadrant.com>, Ron Mayer <rm_pg@cheapcomplexdevices.com>, Euler Taveira de Oliveira <euler@timbira.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2009-06-02T14:38:27Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes: > On Jun 2, 2009, at 9:41 AM, Simon Riggs <simon@2ndQuadrant.com> wrote: >> You're right that the number of significant digits already exceeds the >> true accuracy of the computation. I think what Robert wants to see is >> the exact value used in the calc, so the estimates can be checked more >> thoroughly than is currently possible. > Bingo. Uh, the planner's estimate *is* an integer. What was under discussion (I thought) was showing some fractional digits in the case where EXPLAIN ANALYZE is outputting a measured row count that is an average over multiple loops, and therefore isn't necessarily an integer. In that case the measured value can be considered arbitrarily precise --- though I think in practice one or two fractional digits would be plenty. regards, tom lane
Commits
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EXPLAIN: Always use two fractional digits for row counts.
- 95dbd827f2ed 18.0 landed
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Adjust EXPLAIN test case to filter out "Actual Rows" values.
- 44cbba9a7f51 18.0 cited
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Allow EXPLAIN to indicate fractional rows.
- ddb17e387aa2 18.0 landed
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Fix pgbench performance issue induced by commit af35fe501.
- fb056564ec5b 18.0 cited