Pavel Stehule <pavel.stehule@gmail.com> writes:
> explain analyze signalise one deleted row, but this is not true
This is not a bug. The explain output tells you that one row was
found by the seqscan, which is true. It doesn't tell you whether
the delete machinery did anything with that row. The row could
be suppressed from deletion by a BEFORE DELETE trigger, or because
it was already updated in the current command (as is the case here).
regards, tom lane
