Header And Logo
|
#include "postgres.h"#include <signal.h>#include <sys/time.h>#include <unistd.h>#include "access/xlog.h"#include "access/xlog_internal.h"#include "libpq/pqsignal.h"#include "miscadmin.h"#include "pgstat.h"#include "postmaster/bgwriter.h"#include "replication/syncrep.h"#include "storage/bufmgr.h"#include "storage/fd.h"#include "storage/ipc.h"#include "storage/lwlock.h"#include "storage/proc.h"#include "storage/shmem.h"#include "storage/smgr.h"#include "storage/spin.h"#include "utils/guc.h"#include "utils/memutils.h"#include "utils/resowner.h"
Go to the source code of this file.
| #define WRITES_PER_ABSORB 1000 |
Definition at line 139 of file checkpointer.c.
| void AbsorbFsyncRequests | ( | void | ) |
Definition at line 1299 of file checkpointer.c.
References AmCheckpointerProcess, BgWriterStats, CheckpointerCommLock, END_CRIT_SECTION, CheckpointerRequest::forknum, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), PgStat_MsgBgWriter::m_buf_fsync_backend, PgStat_MsgBgWriter::m_buf_written_backend, CheckpointerShmemStruct::num_backend_fsync, CheckpointerShmemStruct::num_backend_writes, CheckpointerShmemStruct::num_requests, palloc(), pfree(), RememberFsyncRequest(), CheckpointerShmemStruct::requests, CheckpointerRequest::rnode, CheckpointerRequest::segno, and START_CRIT_SECTION.
Referenced by CheckpointerMain(), CheckpointWriteDelay(), mdpostckpt(), and mdsync().
{
CheckpointerRequest *requests = NULL;
CheckpointerRequest *request;
int n;
if (!AmCheckpointerProcess())
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.
*/
START_CRIT_SECTION();
/*
* We try to avoid holding the lock for a long time by copying the request
* array.
*/
LWLockAcquire(CheckpointerCommLock, LW_EXCLUSIVE);
/* Transfer stats counts into pending pgstats message */
BgWriterStats.m_buf_written_backend += CheckpointerShmem->num_backend_writes;
BgWriterStats.m_buf_fsync_backend += CheckpointerShmem->num_backend_fsync;
CheckpointerShmem->num_backend_writes = 0;
CheckpointerShmem->num_backend_fsync = 0;
n = CheckpointerShmem->num_requests;
if (n > 0)
{
requests = (CheckpointerRequest *) palloc(n * sizeof(CheckpointerRequest));
memcpy(requests, CheckpointerShmem->requests, n * sizeof(CheckpointerRequest));
}
CheckpointerShmem->num_requests = 0;
LWLockRelease(CheckpointerCommLock);
for (request = requests; n > 0; request++, n--)
RememberFsyncRequest(request->rnode, request->forknum, request->segno);
if (requests)
pfree(requests);
END_CRIT_SECTION();
}
| static void CheckArchiveTimeout | ( | void | ) | [static] |
Definition at line 594 of file checkpointer.c.
References DEBUG1, ereport, errmsg(), GetLastSegSwitchTime(), last_xlog_switch_time, Max, NULL, RecoveryInProgress(), RequestXLogSwitch(), XLogArchiveTimeout, and XLogSegSize.
Referenced by CheckpointerMain(), and CheckpointWriteDelay().
{
pg_time_t now;
pg_time_t last_time;
if (XLogArchiveTimeout <= 0 || RecoveryInProgress())
return;
now = (pg_time_t) time(NULL);
/* First we do a quick check using possibly-stale local state. */
if ((int) (now - last_xlog_switch_time) < XLogArchiveTimeout)
return;
/*
* Update local state ... note that last_xlog_switch_time is the last time
* a switch was performed *or requested*.
*/
last_time = GetLastSegSwitchTime();
last_xlog_switch_time = Max(last_xlog_switch_time, last_time);
/* Now we can do the real check */
if ((int) (now - last_xlog_switch_time) >= XLogArchiveTimeout)
{
XLogRecPtr switchpoint;
/* OK, it's time to switch */
switchpoint = RequestXLogSwitch();
/*
* If the returned pointer points exactly to a segment boundary,
* assume nothing happened.
*/
if ((switchpoint % XLogSegSize) != 0)
ereport(DEBUG1,
(errmsg("transaction log switch forced (archive_timeout=%d)",
XLogArchiveTimeout)));
/*
* Update state in any case, so we don't retry constantly when the
* system is idle.
*/
last_xlog_switch_time = now;
}
}
| void CheckpointerMain | ( | void | ) |
Definition at line 192 of file checkpointer.c.
References AbortBufferIO(), AbsorbFsyncRequests(), ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE, ALLOCSET_DEFAULT_MINSIZE, AllocSetContextCreate(), AtEOXact_Buffers(), AtEOXact_Files(), AtEOXact_HashTables(), AtEOXact_SMgr(), BgWriterStats, BlockSig, CheckArchiveTimeout(), CHECKPOINT_CAUSE_XLOG, CHECKPOINT_END_OF_RECOVERY, checkpoint_requested, CheckpointerShmemStruct::checkpointer_pid, PROC_HDR::checkpointerLatch, CheckPointTimeout, CheckPointWarning, chkpt_quickdie(), chkpt_sigusr1_handler(), ChkptSigHupHandler(), ckpt_active, ckpt_cached_elapsed, CheckpointerShmemStruct::ckpt_done, CheckpointerShmemStruct::ckpt_failed, CheckpointerShmemStruct::ckpt_flags, CheckpointerShmemStruct::ckpt_lck, ckpt_start_recptr, ckpt_start_time, CheckpointerShmemStruct::ckpt_started, CreateCheckPoint(), CreateRestartPoint(), CurrentResourceOwner, elog, EmitErrorReport(), ereport, errhint(), errmsg_plural(), error_context_stack, ExitOnAnyError, FATAL, FlushErrorState(), GetInsertRecPtr(), got_SIGHUP, HOLD_INTERRUPTS, last_checkpoint_time, last_xlog_switch_time, LOG, LWLockReleaseAll(), PgStat_MsgBgWriter::m_requested_checkpoints, PgStat_MsgBgWriter::m_timed_checkpoints, MemoryContextResetAndDeleteChildren(), MemoryContextSwitchTo(), Min, MyProc, MyProcPid, NULL, PG_exception_stack, PG_SETMASK, pg_usleep(), PGC_SIGHUP, pgstat_send_bgwriter(), pqsignal(), proc_exit(), ProcessConfigFile(), ProcGlobal, PGPROC::procLatch, RecoveryInProgress(), ReqCheckpointHandler(), ReqShutdownHandler(), ResetLatch(), RESOURCE_RELEASE_BEFORE_LOCKS, ResourceOwnerCreate(), ResourceOwnerRelease(), RESUME_INTERRUPTS, shutdown_requested, ShutdownXLOG(), SIG_DFL, SIG_IGN, SIGALRM, SIGCHLD, SIGCONT, sigdelset, SIGHUP, sigjmp_buf, SIGPIPE, SIGQUIT, sigsetjmp, SIGTTIN, SIGTTOU, SIGUSR1, SIGUSR2, SIGWINCH, smgrcloseall(), SpinLockAcquire, SpinLockRelease, TopMemoryContext, UnBlockSig, UnlockBuffers(), UpdateSharedMemoryConfig(), WaitLatch(), WL_LATCH_SET, WL_POSTMASTER_DEATH, WL_TIMEOUT, and XLogArchiveTimeout.
Referenced by AuxiliaryProcessMain().
{
sigjmp_buf local_sigjmp_buf;
MemoryContext checkpointer_context;
CheckpointerShmem->checkpointer_pid = MyProcPid;
/*
* If possible, make this process a group leader, so that the postmaster
* can signal any child processes too. (checkpointer probably never has
* any child processes, but for consistency we make all postmaster child
* processes do this.)
*/
#ifdef HAVE_SETSID
if (setsid() < 0)
elog(FATAL, "setsid() failed: %m");
#endif
/*
* Properly accept or ignore signals the postmaster might send us
*
* 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).
*/
pqsignal(SIGHUP, ChkptSigHupHandler); /* set flag to read config
* file */
pqsignal(SIGINT, ReqCheckpointHandler); /* request checkpoint */
pqsignal(SIGTERM, SIG_IGN); /* ignore SIGTERM */
pqsignal(SIGQUIT, chkpt_quickdie); /* hard crash time */
pqsignal(SIGALRM, SIG_IGN);
pqsignal(SIGPIPE, SIG_IGN);
pqsignal(SIGUSR1, chkpt_sigusr1_handler);
pqsignal(SIGUSR2, ReqShutdownHandler); /* request shutdown */
/*
* Reset some signals that are accepted by postmaster but not here
*/
pqsignal(SIGCHLD, SIG_DFL);
pqsignal(SIGTTIN, SIG_DFL);
pqsignal(SIGTTOU, SIG_DFL);
pqsignal(SIGCONT, SIG_DFL);
pqsignal(SIGWINCH, SIG_DFL);
/* We allow SIGQUIT (quickdie) at all times */
sigdelset(&BlockSig, SIGQUIT);
/*
* Initialize so that first time-driven event happens at the correct time.
*/
last_checkpoint_time = last_xlog_switch_time = (pg_time_t) time(NULL);
/*
* Create a resource owner to keep track of our resources (currently only
* buffer pins).
*/
CurrentResourceOwner = ResourceOwnerCreate(NULL, "Checkpointer");
/*
* 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.
*/
checkpointer_context = AllocSetContextCreate(TopMemoryContext,
"Checkpointer",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
MemoryContextSwitchTo(checkpointer_context);
/*
* If an exception is encountered, processing resumes here.
*
* See notes in postgres.c about the design of this coding.
*/
if (sigsetjmp(local_sigjmp_buf, 1) != 0)
{
/* Since not using PG_TRY, must reset error stack by hand */
error_context_stack = NULL;
/* Prevent interrupts while cleaning up */
HOLD_INTERRUPTS();
/* Report the error to the server log */
EmitErrorReport();
/*
* These operations are really just a minimal subset of
* AbortTransaction(). We don't have very many resources to worry
* about in checkpointer, but we do have LWLocks, buffers, and temp
* files.
*/
LWLockReleaseAll();
AbortBufferIO();
UnlockBuffers();
/* buffer pins are released here: */
ResourceOwnerRelease(CurrentResourceOwner,
RESOURCE_RELEASE_BEFORE_LOCKS,
false, true);
/* we needn't bother with the other ResourceOwnerRelease phases */
AtEOXact_Buffers(false);
AtEOXact_SMgr();
AtEOXact_Files();
AtEOXact_HashTables(false);
/* Warn any waiting backends that the checkpoint failed. */
if (ckpt_active)
{
/* use volatile pointer to prevent code rearrangement */
volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
SpinLockAcquire(&cps->ckpt_lck);
cps->ckpt_failed++;
cps->ckpt_done = cps->ckpt_started;
SpinLockRelease(&cps->ckpt_lck);
ckpt_active = false;
}
/*
* Now return to normal top-level context and clear ErrorContext for
* next time.
*/
MemoryContextSwitchTo(checkpointer_context);
FlushErrorState();
/* Flush any leaked data in the top-level context */
MemoryContextResetAndDeleteChildren(checkpointer_context);
/* Now we can allow interrupts again */
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.
*/
pg_usleep(1000000L);
/*
* Close all open files after any error. This is helpful on Windows,
* where holding deleted files open causes various strange errors.
* It's not clear we need it elsewhere, but shouldn't hurt.
*/
smgrcloseall();
}
/* We can now handle ereport(ERROR) */
PG_exception_stack = &local_sigjmp_buf;
/*
* Unblock signals (they were blocked when the postmaster forked us)
*/
PG_SETMASK(&UnBlockSig);
/*
* Ensure all shared memory values are set correctly for the config. Doing
* this here ensures no race conditions from other concurrent updaters.
*/
UpdateSharedMemoryConfig();
/*
* Advertise our latch that backends can use to wake us up while we're
* sleeping.
*/
ProcGlobal->checkpointerLatch = &MyProc->procLatch;
/*
* Loop forever
*/
for (;;)
{
bool do_checkpoint = false;
int flags = 0;
pg_time_t now;
int elapsed_secs;
int cur_timeout;
int rc;
/* Clear any already-pending wakeups */
ResetLatch(&MyProc->procLatch);
/*
* Process any requests or signals received recently.
*/
AbsorbFsyncRequests();
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
/*
* Checkpointer is the last process to shut down, so we ask it to
* hold the keys for a range of other tasks required most of which
* have nothing to do with checkpointing at all.
*
* For various reasons, some config values can change dynamically
* so the primary copy of them is held in shared memory to make
* sure all backends see the same value. We make Checkpointer
* responsible for updating the shared memory copy if the
* parameter setting changes because of SIGHUP.
*/
UpdateSharedMemoryConfig();
}
if (checkpoint_requested)
{
checkpoint_requested = false;
do_checkpoint = true;
BgWriterStats.m_requested_checkpoints++;
}
if (shutdown_requested)
{
/*
* From here on, elog(ERROR) should end with exit(1), not send
* control back to the sigsetjmp block above
*/
ExitOnAnyError = true;
/* Close down the database */
ShutdownXLOG(0, 0);
/* Normal exit from the checkpointer is here */
proc_exit(0); /* done */
}
/*
* Force a checkpoint if too much time has elapsed since the last one.
* Note that we count a timed checkpoint in stats only when this
* occurs without an external request, but we set the CAUSE_TIME flag
* bit even if there is also an external request.
*/
now = (pg_time_t) time(NULL);
elapsed_secs = now - last_checkpoint_time;
if (elapsed_secs >= CheckPointTimeout)
{
if (!do_checkpoint)
BgWriterStats.m_timed_checkpoints++;
do_checkpoint = true;
flags |= CHECKPOINT_CAUSE_TIME;
}
/*
* Do a checkpoint if requested.
*/
if (do_checkpoint)
{
bool ckpt_performed = false;
bool do_restartpoint;
/* use volatile pointer to prevent code rearrangement */
volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
/*
* Check if we should perform a checkpoint or a restartpoint. As a
* side-effect, RecoveryInProgress() initializes TimeLineID if
* it's not set yet.
*/
do_restartpoint = RecoveryInProgress();
/*
* Atomically fetch the request flags to figure out what kind of a
* checkpoint we should perform, and increase the started-counter
* to acknowledge that we've started a new checkpoint.
*/
SpinLockAcquire(&cps->ckpt_lck);
flags |= cps->ckpt_flags;
cps->ckpt_flags = 0;
cps->ckpt_started++;
SpinLockRelease(&cps->ckpt_lck);
/*
* The end-of-recovery checkpoint is a real checkpoint that's
* performed while we're still in recovery.
*/
if (flags & CHECKPOINT_END_OF_RECOVERY)
do_restartpoint = false;
/*
* We will warn if (a) too soon since last checkpoint (whatever
* caused it) and (b) somebody set the CHECKPOINT_CAUSE_XLOG flag
* since the last checkpoint start. Note in particular that this
* implementation will not generate warnings caused by
* CheckPointTimeout < CheckPointWarning.
*/
if (!do_restartpoint &&
(flags & CHECKPOINT_CAUSE_XLOG) &&
elapsed_secs < CheckPointWarning)
ereport(LOG,
(errmsg_plural("checkpoints are occurring too frequently (%d second apart)",
"checkpoints are occurring too frequently (%d seconds apart)",
elapsed_secs,
elapsed_secs),
errhint("Consider increasing the configuration parameter \"checkpoint_segments\".")));
/*
* Initialize checkpointer-private variables used during
* checkpoint
*/
ckpt_active = true;
if (!do_restartpoint)
ckpt_start_recptr = GetInsertRecPtr();
ckpt_start_time = now;
ckpt_cached_elapsed = 0;
/*
* Do the checkpoint.
*/
if (!do_restartpoint)
{
CreateCheckPoint(flags);
ckpt_performed = true;
}
else
ckpt_performed = CreateRestartPoint(flags);
/*
* After any checkpoint, close all smgr files. This is so we
* won't hang onto smgr references to deleted files indefinitely.
*/
smgrcloseall();
/*
* Indicate checkpoint completion to any waiting backends.
*/
SpinLockAcquire(&cps->ckpt_lck);
cps->ckpt_done = cps->ckpt_started;
SpinLockRelease(&cps->ckpt_lck);
if (ckpt_performed)
{
/*
* 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 = now;
}
else
{
/*
* We were not able to perform the restartpoint (checkpoints
* throw an ERROR in case of error). Most likely because we
* have not received any new checkpoint WAL records since the
* last restartpoint. Try again in 15 s.
*/
last_checkpoint_time = now - CheckPointTimeout + 15;
}
ckpt_active = false;
}
/* Check for archive_timeout and switch xlog files if necessary. */
CheckArchiveTimeout();
/*
* Send off activity statistics to the stats collector. (The reason
* why we re-use bgwriter-related code for this is that the bgwriter
* and checkpointer used to be just one process. It's probably not
* worth the trouble to split the stats support into two independent
* stats message types.)
*/
pgstat_send_bgwriter();
/*
* Sleep until we are signaled or it's time for another checkpoint or
* xlog file switch.
*/
now = (pg_time_t) time(NULL);
elapsed_secs = now - last_checkpoint_time;
if (elapsed_secs >= CheckPointTimeout)
continue; /* no sleep for us ... */
cur_timeout = CheckPointTimeout - elapsed_secs;
if (XLogArchiveTimeout > 0 && !RecoveryInProgress())
{
elapsed_secs = now - last_xlog_switch_time;
if (elapsed_secs >= XLogArchiveTimeout)
continue; /* no sleep for us ... */
cur_timeout = Min(cur_timeout, XLogArchiveTimeout - elapsed_secs);
}
rc = WaitLatch(&MyProc->procLatch,
WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH,
cur_timeout * 1000L /* convert to ms */ );
/*
* Emergency bailout if postmaster has died. This is to avoid the
* necessity for manual cleanup of all postmaster children.
*/
if (rc & WL_POSTMASTER_DEATH)
exit(1);
}
}
| void CheckpointerShmemInit | ( | void | ) |
Definition at line 919 of file checkpointer.c.
References CheckpointerShmemSize(), CheckpointerShmemStruct::ckpt_lck, CheckpointerShmemStruct::max_requests, MemSet, NBuffers, ShmemInitStruct(), and SpinLockInit.
Referenced by CreateSharedMemoryAndSemaphores().
{
Size size = CheckpointerShmemSize();
bool found;
CheckpointerShmem = (CheckpointerShmemStruct *)
ShmemInitStruct("Checkpointer Data",
size,
&found);
if (!found)
{
/*
* First time through, so initialize. Note that we zero the whole
* requests array; this is so that CompactCheckpointerRequestQueue
* can assume that any pad bytes in the request structs are zeroes.
*/
MemSet(CheckpointerShmem, 0, size);
SpinLockInit(&CheckpointerShmem->ckpt_lck);
CheckpointerShmem->max_requests = NBuffers;
}
}
| Size CheckpointerShmemSize | ( | void | ) |
Definition at line 900 of file checkpointer.c.
References add_size(), mul_size(), NBuffers, and offsetof.
Referenced by CheckpointerShmemInit(), and CreateSharedMemoryAndSemaphores().
{
Size size;
/*
* Currently, the size of the requests[] array is arbitrarily set equal to
* NBuffers. This may prove too large or small ...
*/
size = offsetof(CheckpointerShmemStruct, requests);
size = add_size(size, mul_size(NBuffers, sizeof(CheckpointerRequest)));
return size;
}
| void CheckpointWriteDelay | ( | int | flags, | |
| double | progress | |||
| ) |
Definition at line 677 of file checkpointer.c.
References AbsorbFsyncRequests(), AmCheckpointerProcess, CheckArchiveTimeout(), CHECKPOINT_IMMEDIATE, got_SIGHUP, ImmediateCheckpointRequested(), IsCheckpointOnSchedule(), pg_usleep(), PGC_SIGHUP, pgstat_send_bgwriter(), ProcessConfigFile(), shutdown_requested, and UpdateSharedMemoryConfig().
Referenced by BufferSync().
{
static int absorb_counter = WRITES_PER_ABSORB;
/* Do nothing if checkpoint is being executed by non-checkpointer process */
if (!AmCheckpointerProcess())
return;
/*
* Perform the usual duties and take a nap, unless we're behind schedule,
* in which case we just try to catch up as quickly as possible.
*/
if (!(flags & CHECKPOINT_IMMEDIATE) &&
!shutdown_requested &&
!ImmediateCheckpointRequested() &&
IsCheckpointOnSchedule(progress))
{
if (got_SIGHUP)
{
got_SIGHUP = false;
ProcessConfigFile(PGC_SIGHUP);
/* update shmem copies of config variables */
UpdateSharedMemoryConfig();
}
AbsorbFsyncRequests();
absorb_counter = WRITES_PER_ABSORB;
CheckArchiveTimeout();
/*
* Report interim activity statistics to the stats collector.
*/
pgstat_send_bgwriter();
/*
* This sleep used to be connected to bgwriter_delay, typically 200ms.
* That resulted in more frequent wakeups if not much work to do.
* Checkpointer and bgwriter are no longer related so take the Big
* Sleep.
*/
pg_usleep(100000L);
}
else if (--absorb_counter <= 0)
{
/*
* Absorb pending fsync requests after each WRITES_PER_ABSORB write
* operations even when we don't sleep, to prevent overflow of the
* fsync request queue.
*/
AbsorbFsyncRequests();
absorb_counter = WRITES_PER_ABSORB;
}
}
| static void chkpt_quickdie | ( | SIGNAL_ARGS | ) | [static] |
Definition at line 814 of file checkpointer.c.
References BlockSig, on_exit_reset(), and PG_SETMASK.
Referenced by CheckpointerMain().
{
PG_SETMASK(&BlockSig);
/*
* We DO NOT want to run proc_exit() callbacks -- 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. Now that
* there's an atexit callback to prevent third-party code from breaking
* things by calling exit() directly, we have to reset the callbacks
* explicitly to make this work as intended.
*/
on_exit_reset();
/*
* Note we do exit(2) 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. (The "dead man switch" mechanism in pmsignal.c
* should ensure the postmaster sees this as a crash, too, but no harm in
* being doubly sure.)
*/
exit(2);
}
| static void chkpt_sigusr1_handler | ( | SIGNAL_ARGS | ) | [static] |
Definition at line 867 of file checkpointer.c.
References latch_sigusr1_handler().
Referenced by CheckpointerMain().
{
int save_errno = errno;
latch_sigusr1_handler();
errno = save_errno;
}
| static void ChkptSigHupHandler | ( | SIGNAL_ARGS | ) | [static] |
Definition at line 841 of file checkpointer.c.
References got_SIGHUP, MyProc, PGPROC::procLatch, and SetLatch().
Referenced by CheckpointerMain().
{
int save_errno = errno;
got_SIGHUP = true;
if (MyProc)
SetLatch(&MyProc->procLatch);
errno = save_errno;
}
| static bool CompactCheckpointerRequestQueue | ( | void | ) | [static] |
Definition at line 1190 of file checkpointer.c.
References Assert, CheckpointerCommLock, CurrentMemoryContext, DEBUG1, HASHCTL::entrysize, ereport, errmsg(), HASHCTL::hash, HASH_CONTEXT, hash_create(), hash_destroy(), HASH_ELEM, HASH_ENTER, HASH_FUNCTION, hash_search(), HASHCTL::hcxt, HASHCTL::keysize, LWLockHeldByMe(), MemSet, CheckpointerShmemStruct::num_requests, palloc0(), pfree(), and CheckpointerShmemStruct::requests.
Referenced by ForwardFsyncRequest().
{
struct CheckpointerSlotMapping
{
CheckpointerRequest request;
int slot;
};
int n,
preserve_count;
int num_skipped = 0;
HASHCTL ctl;
HTAB *htab;
bool *skip_slot;
/* must hold CheckpointerCommLock in exclusive mode */
Assert(LWLockHeldByMe(CheckpointerCommLock));
/* Initialize skip_slot array */
skip_slot = palloc0(sizeof(bool) * CheckpointerShmem->num_requests);
/* Initialize temporary hash table */
MemSet(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(CheckpointerRequest);
ctl.entrysize = sizeof(struct CheckpointerSlotMapping);
ctl.hash = tag_hash;
ctl.hcxt = CurrentMemoryContext;
htab = hash_create("CompactCheckpointerRequestQueue",
CheckpointerShmem->num_requests,
&ctl,
HASH_ELEM | HASH_FUNCTION | HASH_CONTEXT);
/*
* The basic idea here is that a request can be skipped if it's followed
* by a later, identical request. It might seem more sensible to work
* backwards from the end of the queue and check whether a request is
* *preceded* by an earlier, identical request, in the hopes of doing less
* copying. But that might change the semantics, if there's an
* intervening FORGET_RELATION_FSYNC or FORGET_DATABASE_FSYNC request, so
* we do it this way. It would be possible to be even smarter if we made
* the code below understand the specific semantics of such requests (it
* could blow away preceding entries that would end up being canceled
* anyhow), but it's not clear that the extra complexity would buy us
* anything.
*/
for (n = 0; n < CheckpointerShmem->num_requests; n++)
{
CheckpointerRequest *request;
struct CheckpointerSlotMapping *slotmap;
bool found;
/*
* We use the request struct directly as a hashtable key. This
* assumes that any padding bytes in the structs are consistently the
* same, which should be okay because we zeroed them in
* CheckpointerShmemInit. Note also that RelFileNode had better
* contain no pad bytes.
*/
request = &CheckpointerShmem->requests[n];
slotmap = hash_search(htab, request, HASH_ENTER, &found);
if (found)
{
/* Duplicate, so mark the previous occurrence as skippable */
skip_slot[slotmap->slot] = true;
num_skipped++;
}
/* Remember slot containing latest occurrence of this request value */
slotmap->slot = n;
}
/* Done with the hash table. */
hash_destroy(htab);
/* If no duplicates, we're out of luck. */
if (!num_skipped)
{
pfree(skip_slot);
return false;
}
/* We found some duplicates; remove them. */
preserve_count = 0;
for (n = 0; n < CheckpointerShmem->num_requests; n++)
{
if (skip_slot[n])
continue;
CheckpointerShmem->requests[preserve_count++] = CheckpointerShmem->requests[n];
}
ereport(DEBUG1,
(errmsg("compacted fsync request queue from %d entries to %d entries",
CheckpointerShmem->num_requests, preserve_count)));
CheckpointerShmem->num_requests = preserve_count;
/* Cleanup. */
pfree(skip_slot);
return true;
}
| bool FirstCallSinceLastCheckpoint | ( | void | ) |
Definition at line 1372 of file checkpointer.c.
References CheckpointerShmemStruct::ckpt_done, CheckpointerShmemStruct::ckpt_lck, SpinLockAcquire, and SpinLockRelease.
Referenced by BackgroundWriterMain().
{
/* use volatile pointer to prevent code rearrangement */
volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
static int ckpt_done = 0;
int new_done;
bool FirstCall = false;
SpinLockAcquire(&cps->ckpt_lck);
new_done = cps->ckpt_done;
SpinLockRelease(&cps->ckpt_lck);
if (new_done != ckpt_done)
FirstCall = true;
ckpt_done = new_done;
return FirstCall;
}
| bool ForwardFsyncRequest | ( | RelFileNode | rnode, | |
| ForkNumber | forknum, | |||
| BlockNumber | segno | |||
| ) |
Definition at line 1118 of file checkpointer.c.
References AmBackgroundWriterProcess, AmCheckpointerProcess, CheckpointerShmemStruct::checkpointer_pid, CheckpointerCommLock, PROC_HDR::checkpointerLatch, CompactCheckpointerRequestQueue(), elog, ERROR, CheckpointerRequest::forknum, IsUnderPostmaster, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), CheckpointerShmemStruct::max_requests, CheckpointerShmemStruct::num_backend_fsync, CheckpointerShmemStruct::num_backend_writes, CheckpointerShmemStruct::num_requests, ProcGlobal, CheckpointerShmemStruct::requests, CheckpointerRequest::rnode, CheckpointerRequest::segno, and SetLatch().
Referenced by ForgetDatabaseFsyncRequests(), ForgetRelationFsyncRequests(), register_dirty_segment(), and register_unlink().
{
CheckpointerRequest *request;
bool too_full;
if (!IsUnderPostmaster)
return false; /* probably shouldn't even get here */
if (AmCheckpointerProcess())
elog(ERROR, "ForwardFsyncRequest must not be called in checkpointer");
LWLockAcquire(CheckpointerCommLock, LW_EXCLUSIVE);
/* Count all backend writes regardless of if they fit in the queue */
if (!AmBackgroundWriterProcess())
CheckpointerShmem->num_backend_writes++;
/*
* If the checkpointer isn't running or the request queue is full, the
* backend will have to perform its own fsync request. But before forcing
* that to happen, we can try to compact the request queue.
*/
if (CheckpointerShmem->checkpointer_pid == 0 ||
(CheckpointerShmem->num_requests >= CheckpointerShmem->max_requests &&
!CompactCheckpointerRequestQueue()))
{
/*
* Count the subset of writes where backends have to do their own
* fsync
*/
if (!AmBackgroundWriterProcess())
CheckpointerShmem->num_backend_fsync++;
LWLockRelease(CheckpointerCommLock);
return false;
}
/* OK, insert request */
request = &CheckpointerShmem->requests[CheckpointerShmem->num_requests++];
request->rnode = rnode;
request->forknum = forknum;
request->segno = segno;
/* If queue is more than half full, nudge the checkpointer to empty it */
too_full = (CheckpointerShmem->num_requests >=
CheckpointerShmem->max_requests / 2);
LWLockRelease(CheckpointerCommLock);
/* ... but not till after we release the lock */
if (too_full && ProcGlobal->checkpointerLatch)
SetLatch(ProcGlobal->checkpointerLatch);
return true;
}
| static bool ImmediateCheckpointRequested | ( | void | ) | [static] |
Definition at line 647 of file checkpointer.c.
References CHECKPOINT_IMMEDIATE, checkpoint_requested, and CheckpointerShmemStruct::ckpt_flags.
Referenced by CheckpointWriteDelay().
{
if (checkpoint_requested)
{
volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
/*
* We don't need to acquire the ckpt_lck in this case because we're
* only looking at a single flag bit.
*/
if (cps->ckpt_flags & CHECKPOINT_IMMEDIATE)
return true;
}
return false;
}
| static bool IsCheckpointOnSchedule | ( | double | progress | ) | [static] |
Definition at line 741 of file checkpointer.c.
References Assert, CheckPointCompletionTarget, CheckPointSegments, CheckPointTimeout, ckpt_active, ckpt_cached_elapsed, ckpt_start_recptr, ckpt_start_time, GetInsertRecPtr(), gettimeofday(), NULL, RecoveryInProgress(), and XLogSegSize.
Referenced by CheckpointWriteDelay().
{
XLogRecPtr recptr;
struct timeval now;
double elapsed_xlogs,
elapsed_time;
Assert(ckpt_active);
/* Scale progress according to checkpoint_completion_target. */
progress *= CheckPointCompletionTarget;
/*
* Check against the cached value first. Only do the more expensive
* calculations once we reach the target previously calculated. Since
* neither time or WAL insert pointer moves backwards, a freshly
* calculated value can only be greater than or equal to the cached value.
*/
if (progress < ckpt_cached_elapsed)
return false;
/*
* Check progress against WAL segments written and checkpoint_segments.
*
* We compare the current WAL insert location against the location
* computed before calling CreateCheckPoint. The code in XLogInsert that
* actually triggers a checkpoint when checkpoint_segments is exceeded
* compares against RedoRecptr, so this is not completely accurate.
* However, it's good enough for our purposes, we're only calculating an
* estimate anyway.
*/
if (!RecoveryInProgress())
{
recptr = GetInsertRecPtr();
elapsed_xlogs = (((double) (recptr - ckpt_start_recptr)) / XLogSegSize) / CheckPointSegments;
if (progress < elapsed_xlogs)
{
ckpt_cached_elapsed = elapsed_xlogs;
return false;
}
}
/*
* Check progress against time elapsed and checkpoint_timeout.
*/
gettimeofday(&now, NULL);
elapsed_time = ((double) ((pg_time_t) now.tv_sec - ckpt_start_time) +
now.tv_usec / 1000000.0) / CheckPointTimeout;
if (progress < elapsed_time)
{
ckpt_cached_elapsed = elapsed_time;
return false;
}
/* It looks like we're on schedule. */
return true;
}
| static void ReqCheckpointHandler | ( | SIGNAL_ARGS | ) | [static] |
Definition at line 854 of file checkpointer.c.
References checkpoint_requested, MyProc, PGPROC::procLatch, and SetLatch().
Referenced by CheckpointerMain().
{
int save_errno = errno;
checkpoint_requested = true;
if (MyProc)
SetLatch(&MyProc->procLatch);
errno = save_errno;
}
| static void ReqShutdownHandler | ( | SIGNAL_ARGS | ) | [static] |
Definition at line 878 of file checkpointer.c.
References MyProc, PGPROC::procLatch, SetLatch(), and shutdown_requested.
Referenced by CheckpointerMain().
{
int save_errno = errno;
shutdown_requested = true;
if (MyProc)
SetLatch(&MyProc->procLatch);
errno = save_errno;
}
| void RequestCheckpoint | ( | int | flags | ) |
Definition at line 960 of file checkpointer.c.
References CHECK_FOR_INTERRUPTS, CHECKPOINT_IMMEDIATE, CHECKPOINT_WAIT, CheckpointerShmemStruct::checkpointer_pid, CheckpointerShmemStruct::ckpt_done, CheckpointerShmemStruct::ckpt_failed, CheckpointerShmemStruct::ckpt_flags, CheckpointerShmemStruct::ckpt_lck, CheckpointerShmemStruct::ckpt_started, CreateCheckPoint(), elog, ereport, errhint(), errmsg(), ERROR, IsPostmasterEnvironment, LOG, pg_usleep(), smgrcloseall(), SpinLockAcquire, and SpinLockRelease.
Referenced by createdb(), do_pg_start_backup(), dropdb(), DropTableSpace(), movedb(), standard_ProcessUtility(), StartupXLOG(), XLogPageRead(), and XLogWrite().
{
/* use volatile pointer to prevent code rearrangement */
volatile CheckpointerShmemStruct *cps = CheckpointerShmem;
int ntries;
int old_failed,
old_started;
/*
* If in a standalone backend, just do it ourselves.
*/
if (!IsPostmasterEnvironment)
{
/*
* There's no point in doing slow checkpoints in a standalone backend,
* because there's no other backends the checkpoint could disrupt.
*/
CreateCheckPoint(flags | CHECKPOINT_IMMEDIATE);
/*
* After any checkpoint, close all smgr files. This is so we won't
* hang onto smgr references to deleted files indefinitely.
*/
smgrcloseall();
return;
}
/*
* Atomically set the request flags, and take a snapshot of the counters.
* When we see ckpt_started > old_started, we know the flags we set here
* have been seen by checkpointer.
*
* Note that we OR the flags with any existing flags, to avoid overriding
* a "stronger" request by another backend. The flag senses must be
* chosen to make this work!
*/
SpinLockAcquire(&cps->ckpt_lck);
old_failed = cps->ckpt_failed;
old_started = cps->ckpt_started;
cps->ckpt_flags |= flags;
SpinLockRelease(&cps->ckpt_lck);
/*
* Send signal to request checkpoint. It's possible that the checkpointer
* hasn't started yet, or is in process of restarting, so we will retry a
* few times if needed. Also, if not told to wait for the checkpoint to
* occur, we consider failure to send the signal to be nonfatal and merely
* LOG it.
*/
for (ntries = 0;; ntries++)
{
if (CheckpointerShmem->checkpointer_pid == 0)
{
if (ntries >= 20) /* max wait 2.0 sec */
{
elog((flags & CHECKPOINT_WAIT) ? ERROR : LOG,
"could not request checkpoint because checkpointer not running");
break;
}
}
else if (kill(CheckpointerShmem->checkpointer_pid, SIGINT) != 0)
{
if (ntries >= 20) /* max wait 2.0 sec */
{
elog((flags & CHECKPOINT_WAIT) ? ERROR : LOG,
"could not signal for checkpoint: %m");
break;
}
}
else
break; /* signal sent successfully */
CHECK_FOR_INTERRUPTS();
pg_usleep(100000L); /* wait 0.1 sec, then retry */
}
/*
* If requested, wait for completion. We detect completion according to
* the algorithm given above.
*/
if (flags & CHECKPOINT_WAIT)
{
int new_started,
new_failed;
/* Wait for a new checkpoint to start. */
for (;;)
{
SpinLockAcquire(&cps->ckpt_lck);
new_started = cps->ckpt_started;
SpinLockRelease(&cps->ckpt_lck);
if (new_started != old_started)
break;
CHECK_FOR_INTERRUPTS();
pg_usleep(100000L);
}
/*
* We are waiting for ckpt_done >= new_started, in a modulo sense.
*/
for (;;)
{
int new_done;
SpinLockAcquire(&cps->ckpt_lck);
new_done = cps->ckpt_done;
new_failed = cps->ckpt_failed;
SpinLockRelease(&cps->ckpt_lck);
if (new_done - new_started >= 0)
break;
CHECK_FOR_INTERRUPTS();
pg_usleep(100000L);
}
if (new_failed != old_failed)
ereport(ERROR,
(errmsg("checkpoint request failed"),
errhint("Consult recent messages in the server log for details.")));
}
}
| static void UpdateSharedMemoryConfig | ( | void | ) | [static] |
Definition at line 1353 of file checkpointer.c.
References DEBUG2, elog, SyncRepUpdateSyncStandbysDefined(), and UpdateFullPageWrites().
Referenced by CheckpointerMain(), and CheckpointWriteDelay().
{
/* update global shmem state for sync rep */
SyncRepUpdateSyncStandbysDefined();
/*
* If full_page_writes has been changed by SIGHUP, we update it in shared
* memory and write an XLOG_FPW_CHANGE record.
*/
UpdateFullPageWrites();
elog(DEBUG2, "checkpointer updated shared memory configuration values");
}
volatile sig_atomic_t checkpoint_requested = false [static] |
Definition at line 152 of file checkpointer.c.
Referenced by CheckpointerMain(), ImmediateCheckpointRequested(), and ReqCheckpointHandler().
| double CheckPointCompletionTarget = 0.5 |
Definition at line 146 of file checkpointer.c.
Referenced by IsCheckpointOnSchedule().
CheckpointerShmemStruct* CheckpointerShmem [static] |
Definition at line 136 of file checkpointer.c.
| int CheckPointTimeout = 300 |
Definition at line 144 of file checkpointer.c.
Referenced by CheckpointerMain(), and IsCheckpointOnSchedule().
| int CheckPointWarning = 30 |
Definition at line 145 of file checkpointer.c.
Referenced by CheckpointerMain().
bool ckpt_active = false [static] |
Definition at line 158 of file checkpointer.c.
Referenced by CheckpointerMain(), and IsCheckpointOnSchedule().
double ckpt_cached_elapsed [static] |
Definition at line 163 of file checkpointer.c.
Referenced by CheckpointerMain(), and IsCheckpointOnSchedule().
XLogRecPtr ckpt_start_recptr [static] |
Definition at line 162 of file checkpointer.c.
Referenced by CheckpointerMain(), and IsCheckpointOnSchedule().
pg_time_t ckpt_start_time [static] |
Definition at line 161 of file checkpointer.c.
Referenced by CheckpointerMain(), and IsCheckpointOnSchedule().
volatile sig_atomic_t got_SIGHUP = false [static] |
Definition at line 151 of file checkpointer.c.
Referenced by CheckpointerMain(), CheckpointWriteDelay(), and ChkptSigHupHandler().
pg_time_t last_checkpoint_time [static] |
Definition at line 165 of file checkpointer.c.
Referenced by CheckpointerMain().
pg_time_t last_xlog_switch_time [static] |
Definition at line 166 of file checkpointer.c.
Referenced by CheckArchiveTimeout(), and CheckpointerMain().
volatile sig_atomic_t shutdown_requested = false [static] |
Definition at line 153 of file checkpointer.c.
Referenced by CheckpointerMain(), CheckpointWriteDelay(), and ReqShutdownHandler().
1.7.1