On Mon, Aug 29, 2022 at 3:13 AM Thomas Munro <thomas.mu...@gmail.com> wrote:
> On Mon, Aug 29, 2022 at 9:40 AM Tom Lane <t...@sss.pgh.pa.us> wrote: > > Here's another bit of baggage handling: fixing up the places that > > were afraid to use fflush(NULL). We could doubtless have done > > this years ago (indeed, I found several places already using it) > > but as long as we're making a push to get rid of obsolete code, > > doing it now seems appropriate. > > +1, must be OK (pg_dump and pg_upgrade). > > Archeology: > > commit 79fcde48b229534fd4a5e07834e5e0e84dd38bee > Author: Tom Lane <t...@sss.pgh.pa.us> > Date: Sun Nov 29 01:51:56 1998 +0000 > > Portability fix for old SunOS releases: fflush(NULL) > > > https://www.postgresql.org/message-id/199811241847.NAA04690%40tuna.uimage.com > > SunOS 4.x was still in some kind of support phase for a few more > years, but I guess they weren't working too hard on conformance and > features, given that SunOS 5 (the big BSD -> System V rewrite) had > come out in '92... > > > One thing that's not clear to me is what the appropriate rules > > should be for popen(). POSIX makes clear that you shouldn't > > expect popen() to include an fflush() itself, but we seem quite > > haphazard about whether to do one or not before popen(). In > > the case of popen(..., "r") we can expect that the child can't > > write on our stdout, but stderr could be a problem anyway. > > > > Likewise, there are some places that fflush before system(), > > but they are a minority. Again it seems like the main risk > > is duplicated or mis-ordered stderr output. > > > > I'm inclined to add fflush(NULL) before any popen() or system() > > that hasn't got one already, but did not do that in the attached. > > Couldn't hurt. (Looking around at our setvbuf() setup to check the > expected stream state in various places... and huh, I hadn't > previously noticed the thing about Windows interpreting line buffering > to mean full buffering. Pfnghghl...) > > > The patch does not apply successfully; please rebase the patch. patching file src/backend/postmaster/fork_process.c Hunk #1 FAILED at 37. 1 out of 1 hunk FAILED -- saving rejects to file src/backend/postmaster/fork_process.c.rej patching file src/backend/storage/file/fd.c Hunk #1 FAILED at 2503. 1 out of 1 hunk FAILED -- saving rejects to file src/backend/storage/file/fd.c.rej patching file src/backend/utils/error/elog.c Hunk #1 FAILED at 643. Hunk #2 FAILED at 670. -- Ibrar Ahmed
