Re: BUG #15627: libpq memory leak

PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> PQisBusy has memory leak with next valgrind stack:

> 1: malloc in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so
> 2: PQmakeEmptyPGresult in
> /opt/src/postgres/src/interfaces/libpq/fe-exec.c:146
> 3: getRowDescriptions in
> /opt/src/postgres/src/interfaces/libpq/fe-protocol3.c:492
> 4: pqParseInput3 in
> /opt/src/postgres/src/interfaces/libpq/fe-protocol3.c:293
> 5: parseInput in /opt/src/postgres/src/interfaces/libpq/fe-exec.c:1747
> 6: PQisBusy in /opt/src/postgres/src/interfaces/libpq/fe-exec.c:1764

I don't believe this is actually a leak: what is happening is that
we're collecting the query result that will eventually be returned
by PQgetResult. If the calling program never calls PQgetResult
after PQisBusy, then tools like valgrind might claim that's a leak,
but the claim has nothing to do with reality.

If you think there's a real problem here, please show a self-contained
test case that causes steady increase in memory consumption.

regards, tom lane