diff options
Diffstat (limited to 'src/backend/postmaster/bgwriter.c')
| -rw-r--r-- | src/backend/postmaster/bgwriter.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c index 069e27e427f..c96568149fe 100644 --- a/src/backend/postmaster/bgwriter.c +++ b/src/backend/postmaster/bgwriter.c @@ -115,8 +115,9 @@ BackgroundWriterMain(void) */ pqsignal(SIGCHLD, SIG_DFL); - /* We allow SIGQUIT (quickdie) at all times */ + /* We allow SIGQUIT (SignalHandlerForCrashExit) at all times */ sigdelset(&BlockSig, SIGQUIT); + PG_SETMASK(&BlockSig); /* * We just started, assume there has been either a shutdown or @@ -140,7 +141,20 @@ BackgroundWriterMain(void) /* * If an exception is encountered, processing resumes here. * - * See notes in postgres.c about the design of this coding. + * You might wonder why this isn't coded as an infinite loop around a + * PG_TRY construct. The reason is that this is the bottom of the + * exception stack, and so with PG_TRY there would be no exception handler + * in force at all during the CATCH part. By leaving the outermost setjmp + * always active, we have at least some chance of recovering from an error + * during error recovery. (If we get into an infinite loop thereby, it + * will soon be stopped by overflow of elog.c's internal state stack.) + * + * Note that we use sigsetjmp(..., 1), so that the prevailing signal mask + * (to wit, BlockSig) will be restored when longjmp'ing to here. Thus, + * signals other than SIGQUIT will be blocked until we complete error + * recovery. It might seem that this policy makes the HOLD_INTERRUPTS() + * call redundant, but it is not since InterruptPending might be set + * already. */ if (sigsetjmp(local_sigjmp_buf, 1) != 0) { |