Re: Avoid displaying unnecessary "Recheck Cond" in EXPLAIN ANALYZE output if the bitmap is non-lossy

Bharath Rupireddy <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> writes:
> As specified in $subject, if the bitmap constructed by bitmap index
> scan is non-lossy i.e. row-level bitmap, then showing "Recheck Cond"
> in EXPLAIN ANALYZE output is pointless. However in EXPLAIN without
> ANALYZE we can't say the bitmap is actually a non-lossy one, as we
> don't actually construct the "original" bitmap, so showing "Recheck
> Cond" in this case makes sense.

I do not think this change makes even a little bit of sense.
The recheck condition is part of the plan structure, it is not
execution statistics.

I compare this proposal to having EXPLAIN suppress plan tree nodes
entirely if they weren't executed. We don't do that and it
wouldn't be an improvement. Especially not for non-text output
formats, where the schema of fields that are presented ought to
be fixed for any given plan tree.

regards, tom lane