Re: Ending EXPLAIN ANALYZE early (was Re: That EXPLAIN ANALYZE patch still needs work)

Tom Lane <tgl@sss.pgh.pa.us> writes:

> Gregory Stark <gsstark@mit.edu> writes:
> > Tom Lane <tgl@sss.pgh.pa.us> writes:
> > Would it be possible to make a whole new protocol message for EXPLAIN results?
> 
> I'm really unwilling to get into that.  For one thing, that would
> absolutely positively break *all* use of EXPLAIN from un-fixed clients,
> whether you were trying to stop early or not.

Well I was picturing still having the manual EXPLAIN ANALYZE which works as it
does now replacing the query results in addition to a lower level protocol
request which generates a protocol response with the data.

> > The reason I'm suggesting that is because it might make it easier to implement
> > the SIGINFO handler that sends incremental EXPLAIN results on demand that I
> > was describing earlier.
> 
> Doesn't matter, because that's not happening ;-)  SIGINFO isn't
> portable, and even if it were, a signal handler couldn't possibly
> generate EXPLAIN output (remember those catalog accesses).

Well the signal gets handled by psql. It would have to be a wire protocol
message like Query Cancel that the backend watches for and handles the first
time it can.

-- 
greg