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c627d944e6
Presently, the archiver process restarts when an archive callback ERRORs. To avoid this, archive module authors can use sigsetjmp(), manage a memory context, etc., but that requires a lot of extra code that will likely look roughly the same between modules. This commit adds basic archive callback ERROR handling to pgarch.c so that module authors won't ordinarily need to worry about this. While this built-in handler attempts to clean up anything that an archive module could conceivably have left behind, it is possible that some modules are doing unexpected things that require additional cleanup. Module authors should be sure to do any extra required cleanup in a PG_CATCH block within the archiving callback. The archiving callback is now called in a short-lived memory context that the archiver process resets between invocations. If a module requires longer-lived storage, it must maintain its own memory context. Thanks to these changes, the basic_archive module can be greatly simplified. Suggested-by: Andres Freund Reviewed-by: Andres Freund, Yong Li Discussion: https://postgr.es/m/20230217215624.GA3131134%40nathanxps13
141 lines
3.7 KiB
C
141 lines
3.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* shell_archive.c
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*
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* This archiving function uses a user-specified shell command (the
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* archive_command GUC) to copy write-ahead log files. It is used as the
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* default, but other modules may define their own custom archiving logic.
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*
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* Copyright (c) 2022-2024, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* src/backend/archive/shell_archive.c
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <sys/wait.h>
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#include "access/xlog.h"
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#include "archive/archive_module.h"
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#include "archive/shell_archive.h"
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#include "common/percentrepl.h"
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#include "pgstat.h"
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static bool shell_archive_configured(ArchiveModuleState *state);
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static bool shell_archive_file(ArchiveModuleState *state,
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const char *file,
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const char *path);
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static void shell_archive_shutdown(ArchiveModuleState *state);
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static const ArchiveModuleCallbacks shell_archive_callbacks = {
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.startup_cb = NULL,
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.check_configured_cb = shell_archive_configured,
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.archive_file_cb = shell_archive_file,
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.shutdown_cb = shell_archive_shutdown
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};
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const ArchiveModuleCallbacks *
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shell_archive_init(void)
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{
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return &shell_archive_callbacks;
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}
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static bool
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shell_archive_configured(ArchiveModuleState *state)
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{
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if (XLogArchiveCommand[0] != '\0')
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return true;
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arch_module_check_errdetail("%s is not set.",
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"archive_command");
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return false;
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}
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static bool
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shell_archive_file(ArchiveModuleState *state, const char *file,
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const char *path)
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{
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char *xlogarchcmd;
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char *nativePath = NULL;
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int rc;
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if (path)
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{
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nativePath = pstrdup(path);
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make_native_path(nativePath);
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}
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xlogarchcmd = replace_percent_placeholders(XLogArchiveCommand,
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"archive_command", "fp",
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file, nativePath);
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ereport(DEBUG3,
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(errmsg_internal("executing archive command \"%s\"",
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xlogarchcmd)));
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fflush(NULL);
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pgstat_report_wait_start(WAIT_EVENT_ARCHIVE_COMMAND);
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rc = system(xlogarchcmd);
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pgstat_report_wait_end();
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if (rc != 0)
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{
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/*
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* If either the shell itself, or a called command, died on a signal,
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* abort the archiver. We do this because system() ignores SIGINT and
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* SIGQUIT while waiting; so a signal is very likely something that
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* should have interrupted us too. Also die if the shell got a hard
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* "command not found" type of error. If we overreact it's no big
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* deal, the postmaster will just start the archiver again.
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*/
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int lev = wait_result_is_any_signal(rc, true) ? FATAL : LOG;
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if (WIFEXITED(rc))
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{
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ereport(lev,
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(errmsg("archive command failed with exit code %d",
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WEXITSTATUS(rc)),
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errdetail("The failed archive command was: %s",
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xlogarchcmd)));
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}
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else if (WIFSIGNALED(rc))
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{
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#if defined(WIN32)
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ereport(lev,
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(errmsg("archive command was terminated by exception 0x%X",
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WTERMSIG(rc)),
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errhint("See C include file \"ntstatus.h\" for a description of the hexadecimal value."),
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errdetail("The failed archive command was: %s",
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xlogarchcmd)));
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#else
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ereport(lev,
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(errmsg("archive command was terminated by signal %d: %s",
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WTERMSIG(rc), pg_strsignal(WTERMSIG(rc))),
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errdetail("The failed archive command was: %s",
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xlogarchcmd)));
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#endif
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}
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else
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{
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ereport(lev,
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(errmsg("archive command exited with unrecognized status %d",
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rc),
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errdetail("The failed archive command was: %s",
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xlogarchcmd)));
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}
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return false;
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}
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elog(DEBUG1, "archived write-ahead log file \"%s\"", file);
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return true;
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}
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static void
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shell_archive_shutdown(ArchiveModuleState *state)
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{
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elog(DEBUG1, "archiver process shutting down");
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}
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