318 lines
10 KiB
C++
Executable File
318 lines
10 KiB
C++
Executable File
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/* ---------------------------------------------------------------------------------------
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*
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* walwriterauxiliary.cpp
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*
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* Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd.
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* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* src/backend/postmaster/walwriterauxiliary.cpp
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*
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* ---------------------------------------------------------------------------------------
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*/
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#include <signal.h>
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#include <sys/time.h>
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#include <time.h>
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#include <unistd.h>
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#include <utmpx.h>
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#include <errno.h>
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#ifdef __USE_NUMA
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#include <numa.h>
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#endif
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#include "postgres.h"
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#include "access/xlog.h"
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#include "libpq/pqsignal.h"
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#include "miscadmin.h"
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#include "pgstat.h"
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#include "postmaster/walwriterauxiliary.h"
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#include "storage/buf/bufmgr.h"
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#include "storage/ipc.h"
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#include "storage/lock/lwlock.h"
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#include "storage/proc.h"
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#include "storage/smgr/smgr.h"
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#include "utils/guc.h"
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#include "utils/hsearch.h"
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#include "utils/memutils.h"
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#include "utils/resowner.h"
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#include "gssignal/gs_signal.h"
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/* Signal handlers */
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static void walwriterauxiliary_quickdie(SIGNAL_ARGS);
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static void WalwriterauxiliarySigHupHandler(SIGNAL_ARGS);
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static void WalwriterauxiliaryShutdownHandler(SIGNAL_ARGS);
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static void walwriterauxiliary_sigusr1_handler(SIGNAL_ARGS);
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/*
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* Main entry point for walwriterauxiliary process
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*
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* This is invoked from AuxiliaryProcessMain, which has already created the
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* basic execution environment, but not enabled signals yet.
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*/
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void WalWriterAuxiliaryMain(void)
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{
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sigjmp_buf local_sigjmp_buf;
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MemoryContext walwriterauxiliary_context;
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sigset_t old_sig_mask;
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t_thrd.role = WALWRITERAUXILIARY;
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ereport(LOG, (errmsg("walwriterauxiliary started")));
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/*
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* Properly accept or ignore signals the postmaster might send us
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*
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* We have no particular use for SIGINT at the moment, but seems
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* reasonable to treat like SIGTERM.
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*
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* Reset some signals that are accepted by postmaster but not here.
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*/
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(void)gspqsignal(SIGHUP, WalwriterauxiliarySigHupHandler); /* set flag to read config file */
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(void)gspqsignal(SIGINT, WalwriterauxiliaryShutdownHandler); /* request shutdown */
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(void)gspqsignal(SIGTERM, WalwriterauxiliaryShutdownHandler); /* request shutdown */
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(void)gspqsignal(SIGQUIT, walwriterauxiliary_quickdie); /* hard crash time */
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(void)gspqsignal(SIGALRM, SIG_IGN);
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(void)gspqsignal(SIGPIPE, SIG_IGN);
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(void)gspqsignal(SIGUSR1, walwriterauxiliary_sigusr1_handler);
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(void)gspqsignal(SIGUSR2, SIG_IGN); /* not used */
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(void)gspqsignal(SIGCHLD, SIG_DFL);
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(void)gspqsignal(SIGTTIN, SIG_DFL);
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(void)gspqsignal(SIGTTOU, SIG_DFL);
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(void)gspqsignal(SIGCONT, SIG_DFL);
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(void)gspqsignal(SIGWINCH, SIG_DFL);
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/* We allow SIGQUIT (quickdie) at all times */
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(void)sigdelset(&t_thrd.libpq_cxt.BlockSig, SIGQUIT);
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/*
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* Create a resource owner to keep track of our resources (not clear that
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* we need this, but may as well have one).
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*/
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t_thrd.utils_cxt.CurrentResourceOwner = ResourceOwnerCreate(NULL, "Wal Writer Auxiliary",
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THREAD_GET_MEM_CXT_GROUP(MEMORY_CONTEXT_STORAGE));
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/*
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* Create a memory context that we will do all our work in. We do this so
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* that we can reset the context during error recovery and thereby avoid
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* possible memory leaks. Formerly this code just ran in
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* t_thrd.top_mem_cxt, but resetting that would be a really bad idea.
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*/
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walwriterauxiliary_context = AllocSetContextCreate(t_thrd.top_mem_cxt, "Wal Writer Auxiliary",
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ALLOCSET_DEFAULT_MINSIZE, ALLOCSET_DEFAULT_INITSIZE, ALLOCSET_DEFAULT_MAXSIZE);
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(void)MemoryContextSwitchTo(walwriterauxiliary_context);
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/*
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* If an exception is encountered, processing resumes here.
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*
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* This code is heavily based on bgwriter.c, q.v.
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*/
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if (sigsetjmp(local_sigjmp_buf, 1) != 0) {
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/* We need restore the signal mask of current thread */
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(void)pthread_sigmask(SIG_SETMASK, &old_sig_mask, NULL);
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/* Since not using PG_TRY, must reset error stack by hand */
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t_thrd.log_cxt.error_context_stack = NULL;
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t_thrd.log_cxt.call_stack = NULL;
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/* Prevent interrupts while cleaning up */
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HOLD_INTERRUPTS();
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/* Report the error to the server log */
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EmitErrorReport();
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/* abort async io, must before LWlock release */
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AbortAsyncListIO();
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/* release resource held by lsc */
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AtEOXact_SysDBCache(false);
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/*
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* These operations are really just a minimal subset of
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* AbortTransaction(). We don't have very many resources to worry
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* about in walwriterauxiliary, but we do have LWLocks, and perhaps buffers?
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*/
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LWLockReleaseAll();
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pgstat_report_waitevent(WAIT_EVENT_END);
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AbortBufferIO();
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UnlockBuffers();
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/* buffer pins are released here: */
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ResourceOwnerRelease(t_thrd.utils_cxt.CurrentResourceOwner, RESOURCE_RELEASE_BEFORE_LOCKS, false, true);
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/* we needn't bother with the other ResourceOwnerRelease phases */
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AtEOXact_Buffers(false);
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AtEOXact_SMgr();
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AtEOXact_Files();
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AtEOXact_HashTables(false);
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/*
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* Now return to normal top-level context and clear ErrorContext for
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* next time.
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*/
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(void)MemoryContextSwitchTo(walwriterauxiliary_context);
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FlushErrorState();
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/* Flush any leaked data in the top-level context */
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MemoryContextResetAndDeleteChildren(walwriterauxiliary_context);
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/* Now we can allow interrupts again */
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RESUME_INTERRUPTS();
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/*
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* Sleep at least 1 second after any error. A write error is likely
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* to be repeated, and we don't want to be filling the error logs as
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* fast as we can.
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*/
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pg_usleep(1000000L);
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/*
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* Close all open files after any error. This is helpful on Windows,
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* where holding deleted files open causes various strange errors.
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* It's not clear we need it elsewhere, but shouldn't hurt.
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*/
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smgrcloseall();
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}
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/* We can now handle ereport(ERROR) */
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t_thrd.log_cxt.PG_exception_stack = &local_sigjmp_buf;
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/*
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* Unblock signals (they were blocked when the postmaster forked us)
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*/
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gs_signal_setmask(&t_thrd.libpq_cxt.UnBlockSig, NULL);
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(void)gs_signal_unblock_sigusr2();
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/*
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* Use the recovery target timeline ID during recovery
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*/
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if (RecoveryInProgress()) {
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t_thrd.xlog_cxt.ThisTimeLineID = GetRecoveryTargetTLI();
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}
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/*
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* Advertise our latch that backends can use to wake us up while we're
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* sleeping.
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*/
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g_instance.proc_base->walwriterauxiliaryLatch = &t_thrd.proc->procLatch;
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pgstat_report_appname("Wal Writer Auxiliary");
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pgstat_report_activity(STATE_IDLE, NULL);
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/*
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* Loop forever
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*/
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for (;;) {
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long curTimeout = u_sess->attr.attr_storage.WalWriterDelay;
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int rc = 0;
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/* Clear any already-pending wakeups */
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ResetLatch(&t_thrd.proc->procLatch);
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/*
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* Process any requests or signals received recently.
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*/
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if (t_thrd.walwriterauxiliary_cxt.got_SIGHUP) {
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t_thrd.walwriterauxiliary_cxt.got_SIGHUP = false;
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ProcessConfigFile(PGC_SIGHUP);
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}
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if (t_thrd.walwriterauxiliary_cxt.shutdown_requested) {
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/* Normal exit from the walwriterauxiliary is here. */
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proc_exit(0); /* done */
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}
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if (g_instance.wal_cxt.isWalWriterUp) {
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PGSemaphoreLock(&g_instance.wal_cxt.walInitSegLock->l.sem, true);
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PreInitXlogFileForPrimary(g_instance.attr.attr_storage.wal_file_init_num);
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} else {
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if (g_instance.attr.attr_storage.advance_xlog_file_num > 0 &&
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t_thrd.postmaster_cxt.HaShmData->current_mode == STANDBY_MODE &&
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(pmState == PM_RECOVERY || pmState == PM_HOT_STANDBY) &&
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IsRecoveryDone()) {
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XLogRecPtr curMaxLsn = pg_atomic_read_u64(&g_instance.comm_cxt.predo_cxt.redoPf.local_max_lsn);
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PreInitXlogFileForStandby(curMaxLsn);
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}
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}
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rc = WaitLatch(&t_thrd.proc->procLatch, WL_LATCH_SET | WL_TIMEOUT | WL_POSTMASTER_DEATH, curTimeout);
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if (rc & WL_POSTMASTER_DEATH) {
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gs_thread_exit(1);
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}
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}
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}
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/* --------------------------------
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* signal handler routines
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* --------------------------------
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*/
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/*
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* wal_quickdie() occurs when signalled SIGQUIT by the postmaster.
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*
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* Some backend has bought the farm,
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* so we need to stop what we're doing and exit.
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*/
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static void walwriterauxiliary_quickdie(SIGNAL_ARGS)
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{
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gs_signal_setmask(&t_thrd.libpq_cxt.BlockSig, NULL);
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/*
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* We DO NOT want to run proc_exit() callbacks -- we're here because
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* shared memory may be corrupted, so we don't want to try to clean up our
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* transaction. Just nail the windows shut and get out of town. Now that
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* there's an atexit callback to prevent third-party code from breaking
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* things by calling exit() directly, we have to reset the callbacks
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* explicitly to make this work as intended.
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*/
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on_exit_reset();
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/*
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* Note we do exit(2) not exit(0). This is to force the postmaster into a
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* system reset cycle if some idiot DBA sends a manual SIGQUIT to a random
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* backend. This is necessary precisely because we don't clean up our
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* shared memory state. (The "dead man switch" mechanism in pmsignal.c
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* should ensure the postmaster sees this as a crash, too, but no harm in
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* being doubly sure.)
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*/
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exit(2);
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}
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/* SIGHUP: set flag to re-read config file at next convenient time */
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static void WalwriterauxiliarySigHupHandler(SIGNAL_ARGS)
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{
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int save_errno = errno;
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t_thrd.walwriterauxiliary_cxt.got_SIGHUP = true;
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if (t_thrd.proc)
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SetLatch(&t_thrd.proc->procLatch);
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errno = save_errno;
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}
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/* SIGTERM: set flag to exit normally */
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static void WalwriterauxiliaryShutdownHandler(SIGNAL_ARGS)
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{
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int save_errno = errno;
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t_thrd.walwriterauxiliary_cxt.shutdown_requested = true;
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if (t_thrd.proc)
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SetLatch(&t_thrd.proc->procLatch);
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errno = save_errno;
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}
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/* SIGUSR1: used for latch wakeups */
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static void walwriterauxiliary_sigusr1_handler(SIGNAL_ARGS)
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{
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int save_errno = errno;
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latch_sigusr1_handler();
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errno = save_errno;
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}
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