diff options
Diffstat (limited to 'src/backend/postmaster/bgwriter.c')
| -rw-r--r-- | src/backend/postmaster/bgwriter.c | 109 |
1 files changed, 53 insertions, 56 deletions
diff --git a/src/backend/postmaster/bgwriter.c b/src/backend/postmaster/bgwriter.c index ed1a7b2f27..78fecf4dd6 100644 --- a/src/backend/postmaster/bgwriter.c +++ b/src/backend/postmaster/bgwriter.c @@ -37,7 +37,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.20 2005/09/12 22:20:16 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/postmaster/bgwriter.c,v 1.21 2005/10/15 02:49:23 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -171,11 +171,11 @@ BackgroundWriterMain(void) * * Note: we deliberately ignore SIGTERM, because during a standard Unix * system shutdown cycle, init will SIGTERM all processes at once. We - * want to wait for the backends to exit, whereupon the postmaster - * will tell us it's okay to shut down (via SIGUSR2). + * want to wait for the backends to exit, whereupon the postmaster will + * tell us it's okay to shut down (via SIGUSR2). * - * SIGUSR1 is presently unused; keep it spare in case someday we want - * this process to participate in sinval messaging. + * SIGUSR1 is presently unused; keep it spare in case someday we want this + * process to participate in sinval messaging. */ pqsignal(SIGHUP, BgSigHupHandler); /* set flag to read config file */ pqsignal(SIGINT, ReqCheckpointHandler); /* request checkpoint */ @@ -203,15 +203,15 @@ BackgroundWriterMain(void) #endif /* - * Initialize so that first time-driven checkpoint happens at the - * correct time. + * Initialize so that first time-driven checkpoint happens at the correct + * time. */ last_checkpoint_time = time(NULL); /* - * Create a memory context that we will do all our work in. We do this - * so that we can reset the context during error recovery and thereby - * avoid possible memory leaks. Formerly this code just ran in + * Create a memory context that we will do all our work in. We do this so + * that we can reset the context during error recovery and thereby avoid + * possible memory leaks. Formerly this code just ran in * TopMemoryContext, but resetting that would be a really bad idea. */ bgwriter_context = AllocSetContextCreate(TopMemoryContext, @@ -258,8 +258,8 @@ BackgroundWriterMain(void) } /* - * Now return to normal top-level context and clear ErrorContext - * for next time. + * Now return to normal top-level context and clear ErrorContext for + * next time. */ MemoryContextSwitchTo(bgwriter_context); FlushErrorState(); @@ -271,9 +271,9 @@ BackgroundWriterMain(void) RESUME_INTERRUPTS(); /* - * Sleep at least 1 second after any error. A write error is - * likely to be repeated, and we don't want to be filling the - * error logs as fast as we can. + * Sleep at least 1 second after any error. A write error is likely + * to be repeated, and we don't want to be filling the error logs as + * fast as we can. */ pg_usleep(1000000L); } @@ -329,8 +329,8 @@ BackgroundWriterMain(void) } /* - * Do an unforced checkpoint if too much time has elapsed since - * the last one. + * Do an unforced checkpoint if too much time has elapsed since the + * last one. */ now = time(NULL); elapsed_secs = now - last_checkpoint_time; @@ -346,8 +346,8 @@ BackgroundWriterMain(void) /* * We will warn if (a) too soon since last checkpoint (whatever * caused it) and (b) somebody has set the ckpt_time_warn flag - * since the last checkpoint start. Note in particular that - * this implementation will not generate warnings caused by + * since the last checkpoint start. Note in particular that this + * implementation will not generate warnings caused by * CheckPointTimeout < CheckPointWarning. */ if (BgWriterShmem->ckpt_time_warn && @@ -368,8 +368,7 @@ BackgroundWriterMain(void) /* * After any checkpoint, close all smgr files. This is so we - * won't hang onto smgr references to deleted files - * indefinitely. + * won't hang onto smgr references to deleted files indefinitely. */ smgrcloseall(); @@ -381,8 +380,8 @@ BackgroundWriterMain(void) /* * Note we record the checkpoint start time not end time as - * last_checkpoint_time. This is so that time-driven - * checkpoints happen at a predictable spacing. + * last_checkpoint_time. This is so that time-driven checkpoints + * happen at a predictable spacing. */ last_checkpoint_time = now; } @@ -390,13 +389,13 @@ BackgroundWriterMain(void) BgBufferSync(); /* - * Nap for the configured time, or sleep for 10 seconds if there - * is no bgwriter activity configured. + * Nap for the configured time, or sleep for 10 seconds if there is no + * bgwriter activity configured. * - * On some platforms, signals won't interrupt the sleep. To ensure - * we respond reasonably promptly when someone signals us, break - * down the sleep into 1-second increments, and check for - * interrupts after each nap. + * On some platforms, signals won't interrupt the sleep. To ensure we + * respond reasonably promptly when someone signals us, break down the + * sleep into 1-second increments, and check for interrupts after each + * nap. * * We absorb pending requests after each short sleep. */ @@ -437,13 +436,13 @@ bg_quickdie(SIGNAL_ARGS) /* * DO NOT proc_exit() -- we're here because shared memory may be - * corrupted, so we don't want to try to clean up our transaction. - * Just nail the windows shut and get out of town. + * corrupted, so we don't want to try to clean up our transaction. Just + * nail the windows shut and get out of town. * - * Note we do exit(1) not exit(0). This is to force the postmaster into - * a system reset cycle if some idiot DBA sends a manual SIGQUIT to a - * random backend. This is necessary precisely because we don't clean - * up our shared memory state. + * Note we do exit(1) not exit(0). This is to force the postmaster into a + * system reset cycle if some idiot DBA sends a manual SIGQUIT to a random + * backend. This is necessary precisely because we don't clean up our + * shared memory state. */ exit(1); } @@ -485,8 +484,8 @@ BgWriterShmemSize(void) Size size; /* - * Currently, the size of the requests[] array is arbitrarily set - * equal to NBuffers. This may prove too large or small ... + * Currently, the size of the requests[] array is arbitrarily set equal to + * NBuffers. This may prove too large or small ... */ size = offsetof(BgWriterShmemStruct, requests); size = add_size(size, mul_size(NBuffers, sizeof(BgWriterRequest))); @@ -546,9 +545,8 @@ RequestCheckpoint(bool waitforit, bool warnontime) CreateCheckPoint(false, true); /* - * After any checkpoint, close all smgr files. This is so we - * won't hang onto smgr references to deleted files - * indefinitely. + * After any checkpoint, close all smgr files. This is so we won't + * hang onto smgr references to deleted files indefinitely. */ smgrcloseall(); @@ -571,8 +569,8 @@ RequestCheckpoint(bool waitforit, bool warnontime) "could not signal for checkpoint: %m"); /* - * If requested, wait for completion. We detect completion according - * to the algorithm given above. + * If requested, wait for completion. We detect completion according to + * the algorithm given above. */ if (waitforit) { @@ -585,13 +583,12 @@ RequestCheckpoint(bool waitforit, bool warnontime) /* * We are waiting for ckpt_done >= old_started, in a modulo sense. - * This is a little tricky since we don't know the width or - * signedness of sig_atomic_t. We make the lowest common - * denominator assumption that it is only as wide as "char". This - * means that this algorithm will cope correctly as long as we - * don't sleep for more than 127 completed checkpoints. (If we - * do, we will get another chance to exit after 128 more - * checkpoints...) + * This is a little tricky since we don't know the width or signedness + * of sig_atomic_t. We make the lowest common denominator assumption + * that it is only as wide as "char". This means that this algorithm + * will cope correctly as long as we don't sleep for more than 127 + * completed checkpoints. (If we do, we will get another chance to + * exit after 128 more checkpoints...) */ while (((signed char) (bgs->ckpt_done - old_started)) < 0) { @@ -666,17 +663,17 @@ AbsorbFsyncRequests(void) return; /* - * We have to PANIC if we fail to absorb all the pending requests - * (eg, because our hashtable runs out of memory). This is because - * the system cannot run safely if we are unable to fsync what we - * have been told to fsync. Fortunately, the hashtable is so small - * that the problem is quite unlikely to arise in practice. + * We have to PANIC if we fail to absorb all the pending requests (eg, + * because our hashtable runs out of memory). This is because the system + * cannot run safely if we are unable to fsync what we have been told to + * fsync. Fortunately, the hashtable is so small that the problem is + * quite unlikely to arise in practice. */ START_CRIT_SECTION(); /* - * We try to avoid holding the lock for a long time by copying the - * request array. + * We try to avoid holding the lock for a long time by copying the request + * array. */ LWLockAcquire(BgWriterCommLock, LW_EXCLUSIVE); |