Sort returns more rows than seq scan?

Pavel Stehule <pavel.stehule@gmail.com> writes:

I don't understand how is possible to get more rows from Sort node than in
nested seq scan?

The "extra" rows are re-fetches triggered by mark/restore requests from
the parent mergejoin. The EXPLAIN instrumentation counts re-fetches as
if they were new rows.

regards, tom lane

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2016-03-01 15:45 GMT+01:00 Tom Lane <tgl@sss.pgh.pa.us>:

Pavel Stehule <pavel.stehule@gmail.com> writes:

I don't understand how is possible to get more rows from Sort node than

in

nested seq scan?

The "extra" rows are re-fetches triggered by mark/restore requests from
the parent mergejoin. The EXPLAIN instrumentation counts re-fetches as
if they were new rows.

aha,

Thank you for explain

Regards

Pavel