Andres Freund <andres@anarazel.de> writes:
> On 2022-08-06 16:09:24 -0700, Noah Misch wrote:
>> From the earliest days of wrasse, the compiler used too much RAM to build
>> preproc.o with --enable-debug. As of 2021-04, the compiler's "acomp" phase
>> needed 10G in one process, and later phases needed 11.6G across two processes.
>> Compilation wrote 3.7G into TMPDIR. Since /tmp consumes RAM+swap, overriding
>> TMPDIR relieved 3.7G of RAM pressure. Even with those protections, wrasse
>> intermittently reaches the 14G limit I impose (via "ulimit -v 14680064"). I
>> had experimented with different optimization levels, but that didn't help.
> Yikes. And it's not like newer compiler versions are likely to be forthcoming
> (12.6 is newest and is from 2017...). Wonder if we should just require gcc on
> solaris... There's a decent amount of stuff we could rip out in that case.
Seems like it's only a matter of time before we add enough stuff to
the grammar that the build fails, period.
However, I wonder why exactly it's so large, and why the backend's gram.o
isn't an even bigger problem. Maybe an effort to cut preproc.o's code
size could yield dividends?
FWIW, my late and unlamented animal gaur was also showing unhappiness with
the size of preproc.o, manifested as a boatload of warnings like
/var/tmp//cc0MHZPD.s:11594: Warning: .stabn: description field '109d3' too big, try a different debug format
which did not happen with gram.o.
Even on a modern Linux:
$ size src/backend/parser/gram.o
text data bss dec hex filename
656568 0 0 656568 a04b8 src/backend/parser/gram.o
$ size src/interfaces/ecpg/preproc/preproc.o
text data bss dec hex filename
912005 188 7348 919541 e07f5 src/interfaces/ecpg/preproc/preproc.o
So there's something pretty bloated there. It doesn't seem like
ecpg's additional productions should justify a nigh 50% code
size increase.
regards, tom lane