Re: 64-bit pgbench V2

Tom Lane wrote:
> Please choose a way that doesn't introduce new portability assumptions.
> The backend gets along fine without strtoll, and I don't see why pgbench
> should have to require it.
>

Funny you should mention this...it turns out there is some code already
there, I just didn't notice it before because it's only the unsigned
64-bit strtoul used, not the signed one I was looking for, and it's only
called in one place I didn't previously check.
src/interfaces/ecpg/ecpglib/data.c does this:

*((unsigned long long int *) (var + offset * act_tuple)) =
strtoull(pval, &scan_length, 10);

The appropriate autoconf magic was in the code all along for both
versions, so my bad not noticing it until now. It even transparently
remaps the BSD-ism of calling it strtoq.

I suspect that this alone isn't sufficient to make the code I'm trying
to wedge into pgbench to always work on the platforms I consider must
haves, because of the weird names like _strtoi64 that Windows uses:
http://msdn.microsoft.com/en-us/library/h80404d3(v=VS.80).aspx In fact,
I wouldn't be surprised to discover the ECPG code above doesn't do the
right thing if compiled with a 64-bit MSVC version. Don't expect that's
a popular combination to explicitly test in a way that hits the code
path where this line is at.

The untested (I need to setup for building Windows to really confirm
this works) next patch attempt I've attached does what I think is the
right general sort of thing here. It extends the autoconf remapping
that was already being done to include the second variation on how the
function needed can be named in a MSVC build. This might improve the
ECPG compatibility issue I theorize could be there on that platform.
Given the autoconf stuff and use of the unsigned version was already a
dependency, I'd rather improve that code (so it's more obvious when it
is broken) than do the refactoring work suggested to re-use the server's
internal 64-bit parsing method instead. I could split this into two
patches instead--"add 64-bit strtoull/strtoll support for MSVC" on the
presumption it's actually broken now (possibly wrong on my part) and
"make pgbench use 64-bit values"--but it's not so complicated as one.

I expect there is almost zero overlap between "needs pgbench setshell to
return >32 bit return values" and "not on a platform with a working
64-bit strtoull variation". What I did to hedge against that was add a
little check to pgbench that lets you confirm whether setshell lines are
limited to 32 bits or not, depending on whether the appropriate function
was found. It tries to fall back to the existing strtol in that case,
and I've put a note when that happens (and matching documentation to
look for it) into the debug output of the program.

I'll continue with testing work here, but what's attached is now the
first form I think this could potentially be committed in once it's
known to be free of obvious bugs (testing at this database scale takes
forever). I can revisit not using the library function instead if Tom
or someone else really opposes this new approach. Given most of the
autoconf bits are already there and the limited number of platforms
where this is a problem, I think there's little gain for doing that work
though.

Style/functional suggestions appreciated.

--
Greg Smith 2ndQuadrant US Baltimore, MD
PostgreSQL Training, Services and Support
greg(at)2ndQuadrant(dot)com www.2ndQuadrant.us