Horton

explain analyze rows=%.0f

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2009-05-29T01:30:14Z
Lists: pgsql-hackers 
I have always assumed that there is some very good reason why EXPLAIN
ANALYZE reports the number of rows as an integer rather than a
floating point value, but in reading explain.c it seems that the
reason is just that we decided to round to zero decimal places.  Any
chance we could reconsider this decision?  I often find myself wanting
to know the value that is here called ntuples, but rounding
ntuples/nloops off to the nearest integer loses too much precision.

(Before someone mentions it, yes that would be a good thing to include
in XML-formatted explain output.  But I don't see that including a
couple of decimal places would hurt the text output format either.)

...Robert

Commits

  1. EXPLAIN: Always use two fractional digits for row counts.

  2. Adjust EXPLAIN test case to filter out "Actual Rows" values.

  3. Allow EXPLAIN to indicate fractional rows.

  4. Fix pgbench performance issue induced by commit af35fe501.