From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@postgresql.org
Subject: Re: recovery modules
Date: Tue, 17 Jan 2023 10:23:56 -0800
Message-ID: <20230117182356.GA3015764@nathanxps13> (raw)
In-Reply-To: <Y8Yy01LBF12k9755@paquier.xyz>
References: <20221229194326.GA296099@nathanxps13>
<20230103175917.GA204418@nathanxps13>
<20230103190538.GA287415@nathanxps13>
<Y75rA+YNIWnJ1zsH@paquier.xyz>
<20230111192901.GA1955161@nathanxps13>
<Y7+pEJbJGcxpvqLF@paquier.xyz>
<20230112181721.GA2103226@nathanxps13>
<Y8T+Yb3oB1wCdEQF@paquier.xyz>
<20230116224040.GB2714038@nathanxps13>
<Y8Yy01LBF12k9755@paquier.xyz>
On Tue, Jan 17, 2023 at 02:32:03PM +0900, Michael Paquier wrote:
> Could it be cleaner in the long term to remove entirely
> BuildRestoreCommand() and move the conversion of the xlogpath with
> make_native_path() one level higher in the stack?
Yeah, this seems cleaner. I removed BuildRestoreCommand() in v8.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.comAttachments:
[text/x-diff] v8-0001-Refactor-code-for-restoring-files-via-shell.patch (13.3K, ../20230117182356.GA3015764@nathanxps13/2-v8-0001-Refactor-code-for-restoring-files-via-shell.patch)
download | inline diff:
From c710f5a9e294b198ce6bb2e8d9404cb26a76b913 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Fri, 23 Dec 2022 16:53:38 -0800
Subject: [PATCH v8 1/2] Refactor code for restoring files via shell.
Presently, restore_command uses a different code path than
archive_cleanup_command and recovery_end_command. These code paths
are similar and can be easily combined.
---
src/backend/access/transam/shell_restore.c | 99 ++++++++++------------
src/backend/access/transam/xlogarchive.c | 1 -
src/common/Makefile | 1 -
src/common/archive.c | 60 -------------
src/common/meson.build | 1 -
src/common/percentrepl.c | 13 +--
src/fe_utils/archive.c | 11 ++-
src/include/common/archive.h | 21 -----
src/tools/msvc/Mkvcbuild.pm | 2 +-
9 files changed, 56 insertions(+), 153 deletions(-)
delete mode 100644 src/common/archive.c
delete mode 100644 src/include/common/archive.h
diff --git a/src/backend/access/transam/shell_restore.c b/src/backend/access/transam/shell_restore.cindex 7753a7d667..4752be0b9f 100644--- a/src/backend/access/transam/shell_restore.c+++ b/src/backend/access/transam/shell_restore.c@@ -20,16 +20,14 @@
#include "access/xlogarchive.h"
#include "access/xlogrecovery.h"
-#include "common/archive.h"
#include "common/percentrepl.h"
#include "storage/ipc.h"
#include "utils/wait_event.h"
-static void ExecuteRecoveryCommand(const char *command,+static bool ExecuteRecoveryCommand(const char *command,
const char *commandName,
- bool failOnSignal,- uint32 wait_event_info,- const char *lastRestartPointFileName);+ bool failOnSignal, bool exitOnSigterm,+ uint32 wait_event_info, int fail_elevel);
/*
* Attempt to execute a shell-based restore command.
@@ -40,25 +38,16 @@ bool
shell_restore(const char *file, const char *path,
const char *lastRestartPointFileName)
{
+ char *nativePath = pstrdup(path);
char *cmd;
- int rc;+ bool ret;
/* Build the restore command to execute */
- cmd = BuildRestoreCommand(recoveryRestoreCommand, path, file,- lastRestartPointFileName);-- ereport(DEBUG3,- (errmsg_internal("executing restore command \"%s\"", cmd)));-- /*- * Copy xlog from archival storage to XLOGDIR- */- fflush(NULL);- pgstat_report_wait_start(WAIT_EVENT_RESTORE_COMMAND);- rc = system(cmd);- pgstat_report_wait_end();-- pfree(cmd);+ make_native_path(nativePath);+ cmd = replace_percent_placeholders(recoveryRestoreCommand,+ "restore_command", "frp", file,+ lastRestartPointFileName, nativePath);+ pfree(nativePath);
/*
* Remember, we rollforward UNTIL the restore fails so failure here is
@@ -84,17 +73,11 @@ shell_restore(const char *file, const char *path,
*
* We treat hard shell errors such as "command not found" as fatal, too.
*/
- if (rc != 0)- {- if (wait_result_is_signal(rc, SIGTERM))- proc_exit(1);-- ereport(wait_result_is_any_signal(rc, true) ? FATAL : DEBUG2,- (errmsg("could not restore file \"%s\" from archive: %s",- file, wait_result_to_str(rc))));- }+ ret = ExecuteRecoveryCommand(cmd, "restore_command", true, true,+ WAIT_EVENT_RESTORE_COMMAND, DEBUG2);+ pfree(cmd);- return (rc == 0);+ return ret;
}
/*
@@ -103,9 +86,14 @@ shell_restore(const char *file, const char *path,
void
shell_archive_cleanup(const char *lastRestartPointFileName)
{
- ExecuteRecoveryCommand(archiveCleanupCommand, "archive_cleanup_command",- false, WAIT_EVENT_ARCHIVE_CLEANUP_COMMAND,- lastRestartPointFileName);+ char *cmd;++ cmd = replace_percent_placeholders(archiveCleanupCommand,+ "archive_cleanup_command",+ "r", lastRestartPointFileName);+ (void) ExecuteRecoveryCommand(cmd, "archive_cleanup_command", false, false,+ WAIT_EVENT_ARCHIVE_CLEANUP_COMMAND, WARNING);+ pfree(cmd);
}
/*
@@ -114,9 +102,14 @@ shell_archive_cleanup(const char *lastRestartPointFileName)
void
shell_recovery_end(const char *lastRestartPointFileName)
{
- ExecuteRecoveryCommand(recoveryEndCommand, "recovery_end_command", true,- WAIT_EVENT_RECOVERY_END_COMMAND,- lastRestartPointFileName);+ char *cmd;++ cmd = replace_percent_placeholders(recoveryEndCommand,+ "recovery_end_command",+ "r", lastRestartPointFileName);+ (void) ExecuteRecoveryCommand(cmd, "recovery_end_command", true, false,+ WAIT_EVENT_RECOVERY_END_COMMAND, WARNING);+ pfree(cmd);
}
/*
@@ -124,27 +117,22 @@ shell_recovery_end(const char *lastRestartPointFileName)
*
* 'command' is the shell command to be executed, 'commandName' is a
* human-readable name describing the command emitted in the logs. If
- * 'failOnSignal' is true and the command is killed by a signal, a FATAL- * error is thrown. Otherwise a WARNING is emitted.+ * 'failOnSignal' is true and the command is killed by a signal, a FATAL error+ * is thrown. Otherwise, 'fail_elevel' is used for the log message. If+ * 'exitOnSigterm' is true and the command is killed by SIGTERM, we exit+ * immediately.
*
- * This is currently used for recovery_end_command and archive_cleanup_command.+ * Returns whether the command succeeded.
*/
-static void+static bool
ExecuteRecoveryCommand(const char *command, const char *commandName,
- bool failOnSignal, uint32 wait_event_info,- const char *lastRestartPointFileName)+ bool failOnSignal, bool exitOnSigterm,+ uint32 wait_event_info, int fail_elevel)
{
- char *xlogRecoveryCmd;
int rc;
Assert(command && commandName);
- /*- * construct the command to be executed- */- xlogRecoveryCmd = replace_percent_placeholders(command, commandName, "r",- lastRestartPointFileName);-
ereport(DEBUG3,
(errmsg_internal("executing %s \"%s\"", commandName, command)));
@@ -153,18 +141,19 @@ ExecuteRecoveryCommand(const char *command, const char *commandName,
*/
fflush(NULL);
pgstat_report_wait_start(wait_event_info);
- rc = system(xlogRecoveryCmd);+ rc = system(command);
pgstat_report_wait_end();
- pfree(xlogRecoveryCmd);-
if (rc != 0)
{
+ if (exitOnSigterm && wait_result_is_signal(rc, SIGTERM))+ proc_exit(1);+
/*
* If the failure was due to any sort of signal, it's best to punt and
* abort recovery. See comments in shell_restore().
*/
- ereport((failOnSignal && wait_result_is_any_signal(rc, true)) ? FATAL : WARNING,+ ereport((failOnSignal && wait_result_is_any_signal(rc, true)) ? FATAL : fail_elevel,
/*------
translator: First %s represents a postgresql.conf parameter name like
"recovery_end_command", the 2nd is the value of that parameter, the
@@ -172,4 +161,6 @@ ExecuteRecoveryCommand(const char *command, const char *commandName,
(errmsg("%s \"%s\": %s", commandName,
command, wait_result_to_str(rc))));
}
++ return (rc == 0);
}
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.cindex b5cb060d55..4b89addf97 100644--- a/src/backend/access/transam/xlogarchive.c+++ b/src/backend/access/transam/xlogarchive.c@@ -22,7 +22,6 @@
#include "access/xlog.h"
#include "access/xlog_internal.h"
#include "access/xlogarchive.h"
-#include "common/archive.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/startup.h"
diff --git a/src/common/Makefile b/src/common/Makefileindex 113029bf7b..2f424a5735 100644--- a/src/common/Makefile+++ b/src/common/Makefile@@ -46,7 +46,6 @@ LIBS += $(PTHREAD_LIBS)
# If you add objects here, see also src/tools/msvc/Mkvcbuild.pm
OBJS_COMMON = \
- archive.o \
base64.o \
checksum_helper.o \
compression.o \
diff --git a/src/common/archive.c b/src/common/archive.cdeleted file mode 100644index 641a58ee88..0000000000--- a/src/common/archive.c+++ /dev/null@@ -1,60 +0,0 @@-/*-------------------------------------------------------------------------- *- * archive.c- * Common WAL archive routines- *- * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group- * Portions Copyright (c) 1994, Regents of the University of California- *- *- * IDENTIFICATION- * src/common/archive.c- *- *-------------------------------------------------------------------------- */--#ifndef FRONTEND-#include "postgres.h"-#else-#include "postgres_fe.h"-#endif--#include "common/archive.h"-#include "common/percentrepl.h"--/*- * BuildRestoreCommand- *- * Builds a restore command to retrieve a file from WAL archives, replacing- * the supported aliases with values supplied by the caller as defined by- * the GUC parameter restore_command: xlogpath for %p, xlogfname for %f and- * lastRestartPointFname for %r.- *- * The result is a palloc'd string for the restore command built. The- * caller is responsible for freeing it. If any of the required arguments- * is NULL and that the corresponding alias is found in the command given- * by the caller, then an error is thrown.- */-char *-BuildRestoreCommand(const char *restoreCommand,- const char *xlogpath,- const char *xlogfname,- const char *lastRestartPointFname)-{- char *nativePath = NULL;- char *result;-- if (xlogpath)- {- nativePath = pstrdup(xlogpath);- make_native_path(nativePath);- }-- result = replace_percent_placeholders(restoreCommand, "restore_command", "frp",- xlogfname, lastRestartPointFname, nativePath);-- if (nativePath)- pfree(nativePath);-- return result;-}diff --git a/src/common/meson.build b/src/common/meson.buildindex 41bd58ebdf..1caa1fed04 100644--- a/src/common/meson.build+++ b/src/common/meson.build@@ -1,7 +1,6 @@
# Copyright (c) 2022-2023, PostgreSQL Global Development Group
common_sources = files(
- 'archive.c',
'base64.c',
'checksum_helper.c',
'compression.c',
diff --git a/src/common/percentrepl.c b/src/common/percentrepl.cindex d78571fec0..c083fd9b89 100644--- a/src/common/percentrepl.c+++ b/src/common/percentrepl.c@@ -38,11 +38,6 @@
* This throws an error for an unsupported placeholder or a "%" at the end of
* the input string.
*
- * A value may be NULL. If the corresponding placeholder is found in the- * input string, it will be treated as if an unsupported placeholder was used.- * This allows callers to share a "letters" specification but vary the- * actually supported placeholders at run time.- *
* This functions is meant for cases where all the values are readily
* available or cheap to compute and most invocations will use most values
* (for example for archive_command). Also, it requires that all values are
@@ -101,12 +96,8 @@ replace_percent_placeholders(const char *instr, const char *param_name, const ch
if (*sp == *lp)
{
- if (val)- {- appendStringInfoString(&result, val);- found = true;- }- /* If val is NULL, we will report an error. */+ appendStringInfoString(&result, val);+ found = true;
break;
}
}
diff --git a/src/fe_utils/archive.c b/src/fe_utils/archive.cindex eb1c930ae7..c1ce250c90 100644--- a/src/fe_utils/archive.c+++ b/src/fe_utils/archive.c@@ -19,8 +19,8 @@
#include <sys/stat.h>
#include "access/xlog_internal.h"
-#include "common/archive.h"
#include "common/logging.h"
+#include "common/percentrepl.h"
#include "fe_utils/archive.h"
@@ -41,13 +41,18 @@ RestoreArchivedFile(const char *path, const char *xlogfname,
{
char xlogpath[MAXPGPATH];
char *xlogRestoreCmd;
+ char *nativePath;
int rc;
struct stat stat_buf;
snprintf(xlogpath, MAXPGPATH, "%s/" XLOGDIR "/%s", path, xlogfname);
- xlogRestoreCmd = BuildRestoreCommand(restoreCommand, xlogpath,- xlogfname, NULL);+ nativePath = pstrdup(xlogpath);+ make_native_path(nativePath);+ xlogRestoreCmd = replace_percent_placeholders(restoreCommand,+ "restore_command", "fp",+ xlogfname, nativePath);+ pfree(nativePath);
/*
* Execute restore_command, which should copy the missing file from
diff --git a/src/include/common/archive.h b/src/include/common/archive.hdeleted file mode 100644index 95196772c9..0000000000--- a/src/include/common/archive.h+++ /dev/null@@ -1,21 +0,0 @@-/*-------------------------------------------------------------------------- *- * archive.h- * Common WAL archive routines- *- * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group- * Portions Copyright (c) 1994, Regents of the University of California- *- * src/include/common/archive.h- *- *-------------------------------------------------------------------------- */-#ifndef ARCHIVE_H-#define ARCHIVE_H--extern char *BuildRestoreCommand(const char *restoreCommand,- const char *xlogpath, /* %p */- const char *xlogfname, /* %f */- const char *lastRestartPointFname); /* %r */--#endif /* ARCHIVE_H */diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pmindex f1c9ddf4a0..ee49424d6f 100644--- a/src/tools/msvc/Mkvcbuild.pm+++ b/src/tools/msvc/Mkvcbuild.pm@@ -133,7 +133,7 @@ sub mkvcbuild
}
our @pgcommonallfiles = qw(
- archive.c base64.c checksum_helper.c compression.c+ base64.c checksum_helper.c compression.c
config_info.c controldata_utils.c d2s.c encnames.c exec.c
f2s.c file_perm.c file_utils.c hashfn.c ip.c jsonapi.c
keywords.c kwlookup.c link-canary.c md5_common.c percentrepl.c
--
2.25.1
[text/x-diff] v8-0002-Allow-recovery-via-loadable-modules.patch (51.7K, ../20230117182356.GA3015764@nathanxps13/3-v8-0002-Allow-recovery-via-loadable-modules.patch)
download | inline diff:
From 145f533fffbf8c36eea4d0a45ff558b23339f3b1 Mon Sep 17 00:00:00 2001
From: Nathan Bossart <nathandbossart@gmail.com>
Date: Fri, 9 Dec 2022 19:40:54 -0800
Subject: [PATCH v8 2/2] Allow recovery via loadable modules.
This adds the restore_library parameter to allow archive recovery
via a loadable module, rather than running shell commands.
---
contrib/basic_archive/Makefile | 4 +-
contrib/basic_archive/basic_archive.c | 67 ++++++-
contrib/basic_archive/meson.build | 7 +-
contrib/basic_archive/t/001_restore.pl | 44 +++++
doc/src/sgml/archive-modules.sgml | 168 ++++++++++++++++--
doc/src/sgml/backup.sgml | 43 ++++-
doc/src/sgml/basic-archive.sgml | 33 ++--
doc/src/sgml/config.sgml | 54 +++++-
doc/src/sgml/high-availability.sgml | 23 ++-
src/backend/access/transam/shell_restore.c | 21 ++-
src/backend/access/transam/xlog.c | 13 +-
src/backend/access/transam/xlogarchive.c | 70 +++++++-
src/backend/access/transam/xlogrecovery.c | 26 ++-
src/backend/postmaster/checkpointer.c | 26 +++
src/backend/postmaster/pgarch.c | 7 +-
src/backend/postmaster/startup.c | 23 ++-
src/backend/utils/misc/guc.c | 14 ++
src/backend/utils/misc/guc_tables.c | 10 ++
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/include/access/xlog_internal.h | 1 +
src/include/access/xlogarchive.h | 44 ++++-
src/include/access/xlogrecovery.h | 1 +
src/include/utils/guc.h | 2 +
23 files changed, 618 insertions(+), 84 deletions(-)
create mode 100644 contrib/basic_archive/t/001_restore.pl
diff --git a/contrib/basic_archive/Makefile b/contrib/basic_archive/Makefileindex 55d299d650..487dc563f3 100644--- a/contrib/basic_archive/Makefile+++ b/contrib/basic_archive/Makefile@@ -1,7 +1,7 @@
# contrib/basic_archive/Makefile
MODULES = basic_archive
-PGFILEDESC = "basic_archive - basic archive module"+PGFILEDESC = "basic_archive - basic archive and recovery module"
REGRESS = basic_archive
REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/basic_archive/basic_archive.conf
@@ -9,6 +9,8 @@ REGRESS_OPTS = --temp-config $(top_srcdir)/contrib/basic_archive/basic_archive.c
# which typical installcheck users do not have (e.g. buildfarm clients).
NO_INSTALLCHECK = 1
+TAP_TESTS = 1+
ifdef USE_PGXS
PG_CONFIG = pg_config
PGXS := $(shell $(PG_CONFIG) --pgxs)
diff --git a/contrib/basic_archive/basic_archive.c b/contrib/basic_archive/basic_archive.cindex 28cbb6cce0..8c333c8f99 100644--- a/contrib/basic_archive/basic_archive.c+++ b/contrib/basic_archive/basic_archive.c@@ -17,6 +17,11 @@
* a file is successfully archived and then the system crashes before
* a durable record of the success has been made.
*
+ * This file also demonstrates a basic restore library implementation that+ * is roughly equivalent to the following shell command:+ *+ * cp /path/to/archivedir/%f %p+ *
* Copyright (c) 2022-2023, PostgreSQL Global Development Group
*
* IDENTIFICATION
@@ -30,6 +35,7 @@
#include <sys/time.h>
#include <unistd.h>
+#include "access/xlogarchive.h"
#include "common/int.h"
#include "miscadmin.h"
#include "postmaster/pgarch.h"
@@ -48,6 +54,8 @@ static bool basic_archive_file(const char *file, const char *path);
static void basic_archive_file_internal(const char *file, const char *path);
static bool check_archive_directory(char **newval, void **extra, GucSource source);
static bool compare_files(const char *file1, const char *file2);
+static bool basic_restore_file(const char *file, const char *path,+ const char *lastRestartPointFileName);
/*
* _PG_init
@@ -87,6 +95,19 @@ _PG_archive_module_init(ArchiveModuleCallbacks *cb)
cb->archive_file_cb = basic_archive_file;
}
+/*+ * _PG_recovery_module_init+ *+ * Returns the module's restore callback.+ */+void+_PG_recovery_module_init(RecoveryModuleCallbacks *cb)+{+ AssertVariableIsOfType(&_PG_recovery_module_init, RecoveryModuleInit);++ cb->restore_cb = basic_restore_file;+}+
/*
* check_archive_directory
*
@@ -99,8 +120,8 @@ check_archive_directory(char **newval, void **extra, GucSource source)
/*
* The default value is an empty string, so we have to accept that value.
- * Our check_configured callback also checks for this and prevents- * archiving from proceeding if it is still empty.+ * Our check_configured and restore callbacks also check for this and+ * prevent archiving or recovery from proceeding if it is still empty.
*/
if (*newval == NULL || *newval[0] == '\0')
return true;
@@ -368,3 +389,45 @@ compare_files(const char *file1, const char *file2)
return ret;
}
++/*+ * basic_restore_file+ *+ * Retrieves one file from the WAL archives.+ */+static bool+basic_restore_file(const char *file, const char *path,+ const char *lastRestartPointFileName)+{+ char source[MAXPGPATH];+ struct stat st;++ ereport(DEBUG1,+ (errmsg("restoring \"%s\" via basic_archive", file)));++ if (archive_directory == NULL || archive_directory[0] == '\0')+ ereport(ERROR,+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),+ errmsg("\"basic_archive.archive_directory\" is not set")));++ /*+ * Check whether the file exists. If not, we return false to indicate that+ * there are no more files to restore.+ */+ snprintf(source, MAXPGPATH, "%s/%s", archive_directory, file);+ if (stat(source, &st) != 0)+ {+ int elevel = (errno == ENOENT) ? DEBUG1 : ERROR;++ ereport(elevel,+ (errcode_for_file_access(),+ errmsg("could not stat file \"%s\": %m", source)));+ return false;+ }++ copy_file(source, unconstify(char *, path));++ ereport(DEBUG1,+ (errmsg("restored \"%s\" via basic_archive", file)));+ return true;+}diff --git a/contrib/basic_archive/meson.build b/contrib/basic_archive/meson.buildindex bc1380e6f6..af4580dea9 100644--- a/contrib/basic_archive/meson.build+++ b/contrib/basic_archive/meson.build@@ -7,7 +7,7 @@ basic_archive_sources = files(
if host_system == 'windows'
basic_archive_sources += rc_lib_gen.process(win32ver_rc, extra_args: [
'--NAME', 'basic_archive',
- '--FILEDESC', 'basic_archive - basic archive module',])+ '--FILEDESC', 'basic_archive - basic archive and recovery module',])
endif
basic_archive = shared_module('basic_archive',
@@ -31,4 +31,9 @@ tests += {
# which typical runningcheck users do not have (e.g. buildfarm clients).
'runningcheck': false,
},
+ 'tap': {+ 'tests': [+ 't/001_restore.pl',+ ],+ },
}
diff --git a/contrib/basic_archive/t/001_restore.pl b/contrib/basic_archive/t/001_restore.plnew file mode 100644index 0000000000..ec8767d740--- /dev/null+++ b/contrib/basic_archive/t/001_restore.pl@@ -0,0 +1,44 @@++# Copyright (c) 2022, PostgreSQL Global Development Group++use strict;+use warnings;+use PostgreSQL::Test::Cluster;+use PostgreSQL::Test::Utils;+use Test::More;++# start a node+my $node = PostgreSQL::Test::Cluster->new('node');+$node->init(has_archiving => 1, allows_streaming => 1);+my $archive_dir = $node->archive_dir;+$archive_dir =~ s!\\!/!g if $PostgreSQL::Test::Utils::windows_os;+$node->append_conf('postgresql.conf', "archive_command = ''");+$node->append_conf('postgresql.conf', "archive_library = 'basic_archive'");+$node->append_conf('postgresql.conf', "basic_archive.archive_directory = '$archive_dir'");+$node->start;++# backup the node+my $backup = 'backup';+$node->backup($backup);++# generate some new WAL files+$node->safe_psql('postgres', "CREATE TABLE test (a INT);");+$node->safe_psql('postgres', "SELECT pg_switch_wal();");+$node->safe_psql('postgres', "INSERT INTO test VALUES (1);");++# shut down the node (this should archive all WAL files)+$node->stop;++# restore from the backup+my $restore = PostgreSQL::Test::Cluster->new('restore');+$restore->init_from_backup($node, $backup, has_restoring => 1, standby => 0);+$restore->append_conf('postgresql.conf', "restore_command = ''");+$restore->append_conf('postgresql.conf', "restore_library = 'basic_archive'");+$restore->append_conf('postgresql.conf', "basic_archive.archive_directory = '$archive_dir'");+$restore->start;++# ensure post-backup WAL was replayed+my $result = $restore->safe_psql("postgres", "SELECT count(*) FROM test;");+is($result, "1", "check restore content");++done_testing();diff --git a/doc/src/sgml/archive-modules.sgml b/doc/src/sgml/archive-modules.sgmlindex ef02051f7f..53e657040b 100644--- a/doc/src/sgml/archive-modules.sgml+++ b/doc/src/sgml/archive-modules.sgml@@ -1,34 +1,40 @@
<!-- doc/src/sgml/archive-modules.sgml -->
<chapter id="archive-modules">
- <title>Archive Modules</title>+ <title>Archive and Recovery Modules</title>
<indexterm zone="archive-modules">
- <primary>Archive Modules</primary>+ <primary>Archive and Recovery Modules</primary>
</indexterm>
<para>
PostgreSQL provides infrastructure to create custom modules for continuous
- archiving (see <xref linkend="continuous-archiving"/>). While archiving via- a shell command (i.e., <xref linkend="guc-archive-command"/>) is much- simpler, a custom archive module will often be considerably more robust and- performant.+ archiving and recovery (see <xref linkend="continuous-archiving"/>). While+ a shell command (e.g., <xref linkend="guc-archive-command"/>,+ <xref linkend="guc-restore-command"/>) is much simpler, a custom module will+ often be considerably more robust and performant.
</para>
<para>
When a custom <xref linkend="guc-archive-library"/> is configured, PostgreSQL
will submit completed WAL files to the module, and the server will avoid
recycling or removing these WAL files until the module indicates that the files
- were successfully archived. It is ultimately up to the module to decide what- to do with each WAL file, but many recommendations are listed at- <xref linkend="backup-archiving-wal"/>.+ were successfully archived. When a custom+ <xref linkend="guc-restore-library"/> is configured, PostgreSQL will use the+ module for recovery actions. It is ultimately up to the module to decide how+ to accomplish each task, but some recommendations are listed at+ <xref linkend="backup-archiving-wal"/> and+ <xref linkend="backup-pitr-recovery"/>.
</para>
<para>
- Archiving modules must at least consist of an initialization function (see- <xref linkend="archive-module-init"/>) and the required callbacks (see- <xref linkend="archive-module-callbacks"/>). However, archive modules are- also permitted to do much more (e.g., declare GUCs and register background- workers).+ Archive and recovery modules must at least consist of an initialization+ function (see <xref linkend="archive-module-init"/> and+ <xref linkend="recovery-module-init"/>) and the required callbacks (see+ <xref linkend="archive-module-callbacks"/> and+ <xref linkend="recovery-module-callbacks"/>). However, archive and recovery+ modules are also permitted to do much more (e.g., declare GUCs and register+ background workers). A module may be used for both+ <varname>archive_library</varname> and <varname>restore_library</varname>.
</para>
<para>
@@ -37,7 +43,7 @@
</para>
<sect1 id="archive-module-init">
- <title>Initialization Functions</title>+ <title>Archive Module Initialization Functions</title>
<indexterm zone="archive-module-init">
<primary>_PG_archive_module_init</primary>
</indexterm>
@@ -64,6 +70,12 @@ typedef void (*ArchiveModuleInit) (struct ArchiveModuleCallbacks *cb);
Only the <function>archive_file_cb</function> callback is required. The
others are optional.
</para>
++ <note>+ <para>+ <varname>archive_library</varname> is only loaded in the archiver process.+ </para>+ </note>
</sect1>
<sect1 id="archive-module-callbacks">
@@ -129,6 +141,132 @@ typedef bool (*ArchiveFileCB) (const char *file, const char *path);
<programlisting>
typedef void (*ArchiveShutdownCB) (void);
+</programlisting>+ </para>+ </sect2>+ </sect1>++ <sect1 id="recovery-module-init">+ <title>Recovery Module Initialization Functions</title>+ <indexterm zone="recovery-module-init">+ <primary>_PG_recovery_module_init</primary>+ </indexterm>+ <para>+ A recovery library is loaded by dynamically loading a shared library with the+ <xref linkend="guc-restore-library"/> as the library base name. The normal+ library search path is used to locate the library. To provide the required+ recovery module callbacks and to indicate that the library is actually a+ recovery module, it needs to provide a function named+ <function>_PG_recovery_module_init</function>. This function is passed a+ struct that needs to be filled with the callback function pointers for+ individual actions.++<programlisting>+typedef struct RecoveryModuleCallbacks+{+ RecoveryRestoreCB restore_cb;+ RecoveryArchiveCleanupCB archive_cleanup_cb;+ RecoveryEndCB recovery_end_cb;+ RecoveryShutdownCB shutdown_cb;+} RecoveryModuleCallbacks;+typedef void (*RecoveryModuleInit) (struct RecoveryModuleCallbacks *cb);+</programlisting>++ The <function>restore_cb</function> callback is required for archive+ recovery, but it is optional for streaming replication. The others are+ always optional.+ </para>++ <note>+ <para>+ <varname>restore_library</varname> is only loaded in the startup and+ checkpointer processes and in single-user mode.+ </para>+ </note>+ </sect1>++ <sect1 id="recovery-module-callbacks">+ <title>Recovery Module Callbacks</title>+ <para>+ The recovery callbacks define the actual behavior of the module. The server+ will call them as required to execute recovery actions.+ </para>++ <sect2 id="recovery-module-restore">+ <title>Restore Callback</title>+ <para>+ The <function>restore_cb</function> callback is called to retrieve a single+ archived segment of the WAL file series for archive recovery or streaming+ replication.++<programlisting>+typedef bool (*RecoveryRestoreCB) (const char *file, const char *path, const char *lastRestartPointFileName);+</programlisting>++ This callback must return <literal>true</literal> only if the file was+ successfully retrieved. If the file is not available in the archives, the+ callback must return <literal>false</literal>.+ <replaceable>file</replaceable> will contain just the file name+ of the WAL file to retrieve, while <replaceable>path</replaceable> contains+ the destination's relative path (including the file name).+ <replaceable>lastRestartPointFileName</replaceable> will contain the name+ of the file containing the last valid restart point. That is the earliest+ file that must be kept to allow a restore to be restartable, so this+ information can be used to truncate the archive to just the minimum+ required to support restarting from the current restore.+ <replaceable>lastRestartPointFileName</replaceable> is typically only used+ by warm-standby configurations (see <xref linkend="warm-standby"/>). Note+ that if multiple standby servers are restoring from the same archive+ directory, you will need to ensure that you do not delete WAL files until+ they are no longer needed by any of the servers.+ </para>+ </sect2>++ <sect2 id="recovery-module-archive-cleanup">+ <title>Archive Cleanup Callback</title>+ <para>+ The <function>archive_cleanup_cb</function> callback is called at every+ restart point and is intended to provide a mechanism for cleaning up old+ archived WAL files that are no longer needed by the standby server.++<programlisting>+typedef void (*RecoveryArchiveCleanupCB) (const char *lastRestartPointFileName);+</programlisting>++ <replaceable>lastRestartPointFileName</replaceable> will contain the name+ of the file containing the last valid restart point, like in+ <link linkend="recovery-module-restore"><function>restore_cb</function></link>.+ </para>+ </sect2>++ <sect2 id="recovery-module-end">+ <title>Recovery End Callback</title>+ <para>+ The <function>recovery_end_cb</function> callback is called once at the end+ of recovery and is intended to provide a mechanism for cleanup following+ replication or recovery.++<programlisting>+typedef void (*RecoveryEndCB) (const char *lastRestartPointFileName);+</programlisting>++ <replaceable>lastRestartPointFileName</replaceable> will contain the name+ of the file containing the last valid restart point, like in+ <link linkend="recovery-module-restore"><function>restore_cb</function></link>.+ </para>+ </sect2>++ <sect2 id="recovery-module-shutdown">+ <title>Shutdown Callback</title>+ <para>+ The <function>shutdown_cb</function> callback is called when a process that+ has loaded the recovery module exits (e.g., after an error) or the value of+ <xref linkend="guc-restore-library"/> changes. If no+ <function>shutdown_cb</function> is defined, no special action is taken in+ these situations.++<programlisting>+typedef void (*RecoveryShutdownCB) (void);
</programlisting>
</para>
</sect2>
diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgmlindex be05a33205..f44135061d 100644--- a/doc/src/sgml/backup.sgml+++ b/doc/src/sgml/backup.sgml@@ -1180,9 +1180,27 @@ SELECT * FROM pg_backup_stop(wait_for_archive => true);
<para>
The key part of all this is to set up a recovery configuration that
describes how you want to recover and how far the recovery should
- run. The one thing that you absolutely must specify is the <varname>restore_command</varname>,- which tells <productname>PostgreSQL</productname> how to retrieve archived- WAL file segments. Like the <varname>archive_command</varname>, this is+ run. The one thing that you absolutely must specify is either+ <varname>restore_command</varname> or a <varname>restore_library</varname>+ that defines a restore callback, which tells+ <productname>PostgreSQL</productname> how to retrieve archived WAL file+ segments.+ </para>++ <para>+ Like the <varname>archive_library</varname> parameter,+ <varname>restore_library</varname> is a shared library. Since such+ libraries are written in <literal>C</literal>, creating your own may+ require considerably more effort than writing a shell command. However,+ recovery modules can be more performant than restoring via shell, and they+ will have access to many useful server resources. For more information+ about creating a <varname>restore_library</varname>, see+ <xref linkend="archive-modules"/>.+ </para>++ <para>+ Like the <varname>archive_command</varname>,+ <varname>restore_command</varname> is
a shell command string. It can contain <literal>%f</literal>, which is
replaced by the name of the desired WAL file, and <literal>%p</literal>,
which is replaced by the path name to copy the WAL file to.
@@ -1201,14 +1219,20 @@ restore_command = 'cp /mnt/server/archivedir/%f %p'
</para>
<para>
- It is important that the command return nonzero exit status on failure.- The command <emphasis>will</emphasis> be called requesting files that are not- present in the archive; it must return nonzero when so asked. This is not- an error condition. An exception is that if the command was terminated by+ It is important that the <varname>restore_command</varname> return nonzero+ exit status on failure, or, if you are using a+ <varname>restore_library</varname>, that the restore function returns+ <literal>false</literal> on failure. The command or library+ <emphasis>will</emphasis> be called requesting files that are not+ present in the archive; it must fail when so asked. This is not+ an error condition. An exception is that if the+ <varname>restore_command</varname> was terminated by
a signal (other than <systemitem>SIGTERM</systemitem>, which is used as
part of a database server shutdown) or an error by the shell (such as
command not found), then recovery will abort and the server will not start
- up.+ up. Likewise, if the restore function provided by the+ <varname>restore_library</varname> emits an <literal>ERROR</literal> or+ <literal>FATAL</literal>, recovery will abort and the server won't start.
</para>
<para>
@@ -1232,7 +1256,8 @@ restore_command = 'cp /mnt/server/archivedir/%f %p'
close as possible given the available WAL segments). Therefore, a normal
recovery will end with a <quote>file not found</quote> message, the exact text
of the error message depending upon your choice of
- <varname>restore_command</varname>. You may also see an error message+ <varname>restore_command</varname> or <varname>restore_library</varname>.+ You may also see an error message
at the start of recovery for a file named something like
<filename>00000001.history</filename>. This is also normal and does not
indicate a problem in simple recovery situations; see
diff --git a/doc/src/sgml/basic-archive.sgml b/doc/src/sgml/basic-archive.sgmlindex 60f23d2855..11fd670dbc 100644--- a/doc/src/sgml/basic-archive.sgml+++ b/doc/src/sgml/basic-archive.sgml@@ -8,17 +8,20 @@
</indexterm>
<para>
- <filename>basic_archive</filename> is an example of an archive module. This- module copies completed WAL segment files to the specified directory. This- may not be especially useful, but it can serve as a starting point for- developing your own archive module. For more information about archive- modules, see <xref linkend="archive-modules"/>.+ <filename>basic_archive</filename> is an example of an archive and recovery+ module. This module copies completed WAL segment files to or from the+ specified directory. This may not be especially useful, but it can serve as+ a starting point for developing your own archive and recovery modules. For+ more information about archive and recovery modules, see+ see <xref linkend="archive-modules"/>.
</para>
<para>
- In order to function, this module must be loaded via+ For use as an archive module, this module must be loaded via
<xref linkend="guc-archive-library"/>, and <xref linkend="guc-archive-mode"/>
- must be enabled.+ must be enabled. For use as a recovery module, this module must be loaded+ via <xref linkend="guc-restore-library"/>, and recovery must be enabled (see+ <xref linkend="runtime-config-wal-archive-recovery"/>).
</para>
<sect2 id="basic-archive-configuration-parameters">
@@ -34,11 +37,12 @@
</term>
<listitem>
<para>
- The directory where the server should copy WAL segment files. This- directory must already exist. The default is an empty string, which- effectively halts WAL archiving, but if <xref linkend="guc-archive-mode"/>- is enabled, the server will accumulate WAL segment files in the- expectation that a value will soon be provided.+ The directory where the server should copy WAL segment files to or from.+ This directory must already exist. The default is an empty string,+ which, when used for archiving, effectively halts WAL archival, but if+ <xref linkend="guc-archive-mode"/> is enabled, the server will accumulate+ WAL segment files in the expectation that a value will soon be provided.+ When an empty string is used for recovery, restore will fail.
</para>
</listitem>
</varlistentry>
@@ -46,7 +50,7 @@
<para>
These parameters must be set in <filename>postgresql.conf</filename>.
- Typical usage might be:+ Typical usage as an archive module might be:
</para>
<programlisting>
@@ -61,7 +65,8 @@ basic_archive.archive_directory = '/path/to/archive/directory'
<title>Notes</title>
<para>
- Server crashes may leave temporary files with the prefix+ When <filename>basic_archive</filename> is used as an archive module, server+ crashes may leave temporary files with the prefix
<filename>archtemp</filename> in the archive directory. It is recommended to
delete such files before restarting the server after a crash. It is safe to
remove such files while the server is running as long as they are unrelated
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgmlindex 77574e2d4e..039d3360ac 100644--- a/doc/src/sgml/config.sgml+++ b/doc/src/sgml/config.sgml@@ -3773,7 +3773,8 @@ include_dir 'conf.d'
recovery when the end of archived WAL is reached, but will keep trying to
continue recovery by connecting to the sending server as specified by the
<varname>primary_conninfo</varname> setting and/or by fetching new WAL
- segments using <varname>restore_command</varname>. For this mode, the+ segments using <varname>restore_command</varname> or+ <varname>restore_library</varname>. For this mode, the
parameters from this section and <xref
linkend="runtime-config-replication-standby"/> are of interest.
Parameters from <xref linkend="runtime-config-wal-recovery-target"/> will
@@ -3801,7 +3802,8 @@ include_dir 'conf.d'
<listitem>
<para>
The local shell command to execute to retrieve an archived segment of
- the WAL file series. This parameter is required for archive recovery,+ the WAL file series. Either <varname>restore_command</varname> or+ <xref linkend="guc-restore-library"/> is required for archive recovery,
but optional for streaming replication.
Any <literal>%f</literal> in the string is
replaced by the name of the file to retrieve from the archive,
@@ -3836,7 +3838,42 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
<para>
This parameter can only be set in the <filename>postgresql.conf</filename>
- file or on the server command line.+ file or on the server command line. It is only used if+ <varname>restore_library</varname> is set to an empty string. If both+ <varname>restore_command</varname> and+ <varname>restore_library</varname> are set, an error will be raised.+ </para>+ </listitem>+ </varlistentry>++ <varlistentry id="guc-restore-library" xreflabel="restore_library">+ <term><varname>restore_library</varname> (<type>string</type>)+ <indexterm>+ <primary><varname>restore_library</varname> configuration parameter</primary>+ </indexterm>+ </term>+ <listitem>+ <para>+ The library to use for recovery actions, including retrieving archived+ segments of the WAL file series and executing tasks at restartpoints+ and at recovery end. Either <xref linkend="guc-restore-command"/> or+ <varname>restore_library</varname> is required for archive recovery,+ but optional for streaming replication. If this parameter is set to an+ empty string (the default), restoring via shell is enabled, and+ <varname>restore_command</varname>,+ <varname>archive_cleanup_command</varname> and+ <varname>recovery_end_command</varname> are used. If both+ <varname>restore_library</varname> and any of+ <varname>restore_command</varname>,+ <varname>archive_cleanup_command</varname> or+ <varname>recovery_end_command</varname> are set, an error will be+ raised. Otherwise, the specified shared library is used for recovery.+ For more information, see <xref linkend="archive-modules"/>.+ </para>++ <para>+ This parameter can only be set in the+ <filename>postgresql.conf</filename> file or on the server command line.
</para>
</listitem>
</varlistentry>
@@ -3881,7 +3918,10 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</para>
<para>
This parameter can only be set in the <filename>postgresql.conf</filename>
- file or on the server command line.+ file or on the server command line. It is only used if+ <varname>restore_library</varname> is set to an empty string. If both+ <varname>archive_cleanup_command</varname> and+ <varname>restore_library</varname> are set, an error will be raised.
</para>
</listitem>
</varlistentry>
@@ -3910,11 +3950,13 @@ restore_command = 'copy "C:\\server\\archivedir\\%f" "%p"' # Windows
</para>
<para>
This parameter can only be set in the <filename>postgresql.conf</filename>
- file or on the server command line.+ file or on the server command line. It is only used if+ <varname>restore_library</varname> is set to an empty string. If both+ <varname>recovery_end_command</varname> and+ <varname>restore_library</varname> are set, an error will be raised.
</para>
</listitem>
</varlistentry>
-
</variablelist>
</sect2>
diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgmlindex f180607528..6266e2df7f 100644--- a/doc/src/sgml/high-availability.sgml+++ b/doc/src/sgml/high-availability.sgml@@ -627,7 +627,8 @@ protocol to make nodes agree on a serializable transactional order.
<para>
In standby mode, the server continuously applies WAL received from the
primary server. The standby server can read WAL from a WAL archive
- (see <xref linkend="guc-restore-command"/>) or directly from the primary+ (see <xref linkend="guc-restore-command"/> and+ <xref linkend="guc-restore-library"/>) or directly from the primary
over a TCP connection (streaming replication). The standby server will
also attempt to restore any WAL found in the standby cluster's
<filename>pg_wal</filename> directory. That typically happens after a server
@@ -638,9 +639,11 @@ protocol to make nodes agree on a serializable transactional order.
<para>
At startup, the standby begins by restoring all WAL available in the
- archive location, calling <varname>restore_command</varname>. Once it- reaches the end of WAL available there and <varname>restore_command</varname>- fails, it tries to restore any WAL available in the <filename>pg_wal</filename> directory.+ archive location, either by calling <varname>restore_command</varname> or+ by executing the <varname>restore_library</varname>'s restore callback.+ Once it reaches the end of WAL available there and+ <varname>restore_command</varname> or the restore callback fails, it tries+ to restore any WAL available in the <filename>pg_wal</filename> directory.
If that fails, and streaming replication has been configured, the
standby tries to connect to the primary server and start streaming WAL
from the last valid record found in archive or <filename>pg_wal</filename>. If that fails
@@ -698,7 +701,8 @@ protocol to make nodes agree on a serializable transactional order.
server (see <xref linkend="backup-pitr-recovery"/>). Create a file
<link linkend="file-standby-signal"><filename>standby.signal</filename></link><indexterm><primary>standby.signal</primary></indexterm>
in the standby's cluster data
- directory. Set <xref linkend="guc-restore-command"/> to a simple command to copy files from+ directory. Set <xref linkend="guc-restore-command"/> or+ <xref linkend="guc-restore-library"/> to copy files from
the WAL archive. If you plan to have multiple standby servers for high
availability purposes, make sure that <varname>recovery_target_timeline</varname> is set to
<literal>latest</literal> (the default), to make the standby server follow the timeline change
@@ -707,7 +711,8 @@ protocol to make nodes agree on a serializable transactional order.
<note>
<para>
- <xref linkend="guc-restore-command"/> should return immediately+ <xref linkend="guc-restore-command"/> and restore callbacks provided by+ <xref linkend="guc-restore-library"/> should return immediately
if the file does not exist; the server will retry the command again if
necessary.
</para>
@@ -731,8 +736,10 @@ protocol to make nodes agree on a serializable transactional order.
<para>
If you're using a WAL archive, its size can be minimized using the <xref
- linkend="guc-archive-cleanup-command"/> parameter to remove files that are no- longer required by the standby server.+ linkend="guc-archive-cleanup-command"/> parameter or the+ <xref linkend="guc-restore-library"/>'s+ <function>archive_cleanup_cb</function> callback function to remove files+ that are no longer required by the standby server.
The <application>pg_archivecleanup</application> utility is designed specifically to
be used with <varname>archive_cleanup_command</varname> in typical single-standby
configurations, see <xref linkend="pgarchivecleanup"/>.
diff --git a/src/backend/access/transam/shell_restore.c b/src/backend/access/transam/shell_restore.cindex 4752be0b9f..90283c601b 100644--- a/src/backend/access/transam/shell_restore.c+++ b/src/backend/access/transam/shell_restore.c@@ -4,7 +4,8 @@
* Recovery functions for a user-specified shell command.
*
* These recovery functions use a user-specified shell command (e.g. based
- * on the GUC restore_command).+ * on the GUC restore_command). It is used as the default, but other+ * modules may define their own recovery logic.
*
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
@@ -24,11 +25,25 @@
#include "storage/ipc.h"
#include "utils/wait_event.h"
+static bool shell_restore(const char *file, const char *path,+ const char *lastRestartPointFileName);+static void shell_archive_cleanup(const char *lastRestartPointFileName);+static void shell_recovery_end(const char *lastRestartPointFileName);
static bool ExecuteRecoveryCommand(const char *command,
const char *commandName,
bool failOnSignal, bool exitOnSigterm,
uint32 wait_event_info, int fail_elevel);
+void+shell_restore_init(RecoveryModuleCallbacks *cb)+{+ AssertVariableIsOfType(&shell_restore_init, RecoveryModuleInit);++ cb->restore_cb = shell_restore;+ cb->archive_cleanup_cb = shell_archive_cleanup;+ cb->recovery_end_cb = shell_recovery_end;+}+
/*
* Attempt to execute a shell-based restore command.
*
@@ -83,7 +98,7 @@ shell_restore(const char *file, const char *path,
/*
* Attempt to execute a shell-based archive cleanup command.
*/
-void+static void
shell_archive_cleanup(const char *lastRestartPointFileName)
{
char *cmd;
@@ -99,7 +114,7 @@ shell_archive_cleanup(const char *lastRestartPointFileName)
/*
* Attempt to execute a shell-based end-of-recovery command.
*/
-void+static void
shell_recovery_end(const char *lastRestartPointFileName)
{
char *cmd;
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.cindex 8f47fb7570..ae537cd87f 100644--- a/src/backend/access/transam/xlog.c+++ b/src/backend/access/transam/xlog.c@@ -4884,15 +4884,16 @@ static void
CleanupAfterArchiveRecovery(TimeLineID EndOfLogTLI, XLogRecPtr EndOfLog,
TimeLineID newTLI)
{
+
/*
- * Execute the recovery_end_command, if any.+ * Execute the recovery-end callback, if any.
*/
- if (recoveryEndCommand && strcmp(recoveryEndCommand, "") != 0)+ if (RecoveryContext.recovery_end_cb)
{
char lastRestartPointFname[MAXFNAMELEN];
GetOldestRestartPointFileName(lastRestartPointFname);
- shell_recovery_end(lastRestartPointFname);+ RecoveryContext.recovery_end_cb(lastRestartPointFname);
}
/*
@@ -7307,14 +7308,14 @@ CreateRestartPoint(int flags)
timestamptz_to_str(xtime)) : 0));
/*
- * Finally, execute archive_cleanup_command, if any.+ * Execute the archive-cleanup callback, if any.
*/
- if (archiveCleanupCommand && strcmp(archiveCleanupCommand, "") != 0)+ if (RecoveryContext.archive_cleanup_cb)
{
char lastRestartPointFname[MAXFNAMELEN];
GetOldestRestartPointFileName(lastRestartPointFname);
- shell_archive_cleanup(lastRestartPointFname);+ RecoveryContext.archive_cleanup_cb(lastRestartPointFname);
}
return true;
diff --git a/src/backend/access/transam/xlogarchive.c b/src/backend/access/transam/xlogarchive.cindex 4b89addf97..4af5689c25 100644--- a/src/backend/access/transam/xlogarchive.c+++ b/src/backend/access/transam/xlogarchive.c@@ -22,6 +22,8 @@
#include "access/xlog.h"
#include "access/xlog_internal.h"
#include "access/xlogarchive.h"
+#include "access/xlogrecovery.h"+#include "fmgr.h"
#include "miscadmin.h"
#include "pgstat.h"
#include "postmaster/startup.h"
@@ -31,6 +33,11 @@
#include "storage/ipc.h"
#include "storage/lwlock.h"
+/*+ * Global context for recovery-related callbacks.+ */+RecoveryModuleCallbacks RecoveryContext;+
/*
* Attempt to retrieve the specified file from off-line archival storage.
* If successful, fill "path" with its complete path (note that this will be
@@ -70,7 +77,7 @@ RestoreArchivedFile(char *path, const char *xlogfname,
goto not_available;
/* In standby mode, restore_command might not be supplied */
- if (recoveryRestoreCommand == NULL || strcmp(recoveryRestoreCommand, "") == 0)+ if (RecoveryContext.restore_cb == NULL)
goto not_available;
/*
@@ -148,14 +155,15 @@ RestoreArchivedFile(char *path, const char *xlogfname,
XLogFileName(lastRestartPointFname, 0, 0L, wal_segment_size);
/*
- * Check signals before restore command and reset afterwards.+ * Check signals before restore callback and reset afterwards.
*/
PreRestoreCommand();
/*
* Copy xlog from archival storage to XLOGDIR
*/
- ret = shell_restore(xlogfname, xlogpath, lastRestartPointFname);+ ret = RecoveryContext.restore_cb(xlogfname, xlogpath,+ lastRestartPointFname);
PostRestoreCommand();
@@ -602,3 +610,59 @@ XLogArchiveCleanup(const char *xlog)
unlink(archiveStatusPath);
/* should we complain about failure? */
}
++/*+ * Loads all the recovery callbacks into our global RecoveryContext. The+ * caller is responsible for validating the combination of library/command+ * parameters that are set (e.g., restore_command and restore_library cannot+ * both be set).+ */+void+LoadRecoveryCallbacks(void)+{+ RecoveryModuleInit init;++ /*+ * If the shell command is enabled, use our special initialization+ * function. Otherwise, load the library and call its+ * _PG_recovery_module_init().+ */+ if (restoreLibrary[0] == '\0')+ init = shell_restore_init;+ else+ init = (RecoveryModuleInit)+ load_external_function(restoreLibrary, "_PG_recovery_module_init",+ false, NULL);++ if (init == NULL)+ ereport(ERROR,+ (errmsg("recovery modules have to define the symbol "+ "_PG_recovery_module_init")));++ memset(&RecoveryContext, 0, sizeof(RecoveryModuleCallbacks));+ (*init) (&RecoveryContext);++ /*+ * If using shell commands, remove callbacks for any commands that are not+ * set.+ */+ if (restoreLibrary[0] == '\0')+ {+ if (recoveryRestoreCommand[0] == '\0')+ RecoveryContext.restore_cb = NULL;+ if (archiveCleanupCommand[0] == '\0')+ RecoveryContext.archive_cleanup_cb = NULL;+ if (recoveryEndCommand[0] == '\0')+ RecoveryContext.recovery_end_cb = NULL;+ }+}++/*+ * Call the shutdown callback of the loaded recovery module, if defined.+ */+void+call_recovery_module_shutdown_cb(int code, Datum arg)+{+ if (RecoveryContext.shutdown_cb)+ RecoveryContext.shutdown_cb();+}diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.cindex 5e65785306..db0cd4469a 100644--- a/src/backend/access/transam/xlogrecovery.c+++ b/src/backend/access/transam/xlogrecovery.c@@ -80,6 +80,7 @@ const struct config_enum_entry recovery_target_action_options[] = {
/* options formerly taken from recovery.conf for archive recovery */
char *recoveryRestoreCommand = NULL;
+char *restoreLibrary = NULL;
char *recoveryEndCommand = NULL;
char *archiveCleanupCommand = NULL;
RecoveryTargetType recoveryTarget = RECOVERY_TARGET_UNSET;
@@ -1053,24 +1054,37 @@ validateRecoveryParameters(void)
if (!ArchiveRecoveryRequested)
return;
+ /*+ * Check for invalid combinations of the command/library parameters and+ * load the callbacks.+ */+ CheckMutuallyExclusiveGUCs(restoreLibrary, "restore_library",+ recoveryRestoreCommand, "restore_command");+ CheckMutuallyExclusiveGUCs(restoreLibrary, "restore_library",+ recoveryEndCommand, "recovery_end_command");+ before_shmem_exit(call_recovery_module_shutdown_cb, 0);+ LoadRecoveryCallbacks();+
/*
* Check for compulsory parameters
*/
if (StandbyModeRequested)
{
if ((PrimaryConnInfo == NULL || strcmp(PrimaryConnInfo, "") == 0) &&
- (recoveryRestoreCommand == NULL || strcmp(recoveryRestoreCommand, "") == 0))+ RecoveryContext.restore_cb == NULL)
ereport(WARNING,
- (errmsg("specified neither primary_conninfo nor restore_command"),- errhint("The database server will regularly poll the pg_wal subdirectory to check for files placed there.")));+ (errmsg("specified neither primary_conninfo nor restore_command "+ "nor a restore_library that defines a restore callback"),+ errhint("The database server will regularly poll the pg_wal "+ "subdirectory to check for files placed there.")));
}
else
{
- if (recoveryRestoreCommand == NULL ||- strcmp(recoveryRestoreCommand, "") == 0)+ if (RecoveryContext.restore_cb == NULL)
ereport(FATAL,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
- errmsg("must specify restore_command when standby mode is not enabled")));+ errmsg("must specify restore_command or a restore_library that defines "+ "a restore callback when standby mode is not enabled")));
}
/*
diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.cindex de0bbbfa79..6350fd0b83 100644--- a/src/backend/postmaster/checkpointer.c+++ b/src/backend/postmaster/checkpointer.c@@ -38,6 +38,7 @@
#include "access/xlog.h"
#include "access/xlog_internal.h"
+#include "access/xlogarchive.h"
#include "access/xlogrecovery.h"
#include "libpq/pqsignal.h"
#include "miscadmin.h"
@@ -222,6 +223,16 @@ CheckpointerMain(void)
*/
before_shmem_exit(pgstat_before_server_shutdown, 0);
+ /*+ * Check for invalid combinations of the command/library parameters and+ * load the callbacks. We do this before setting up the exception handler+ * so that any problems result in a server crash shortly after startup.+ */+ CheckMutuallyExclusiveGUCs(restoreLibrary, "restore_library",+ archiveCleanupCommand, "archive_cleanup_command");+ before_shmem_exit(call_recovery_module_shutdown_cb, 0);+ LoadRecoveryCallbacks();+
/*
* 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
@@ -548,6 +559,9 @@ HandleCheckpointerInterrupts(void)
if (ConfigReloadPending)
{
+ char *prevRestoreLibrary = pstrdup(restoreLibrary);+ char *prevArchiveCleanupCommand = pstrdup(archiveCleanupCommand);+
ConfigReloadPending = false;
ProcessConfigFile(PGC_SIGHUP);
@@ -563,6 +577,18 @@ HandleCheckpointerInterrupts(void)
* because of SIGHUP.
*/
UpdateSharedMemoryConfig();
++ CheckMutuallyExclusiveGUCs(restoreLibrary, "restore_library",+ archiveCleanupCommand, "archive_cleanup_command");+ if (strcmp(prevRestoreLibrary, restoreLibrary) != 0 ||+ strcmp(prevArchiveCleanupCommand, archiveCleanupCommand) != 0)+ {+ call_recovery_module_shutdown_cb(0, (Datum) 0);+ LoadRecoveryCallbacks();+ }++ pfree(prevRestoreLibrary);+ pfree(prevArchiveCleanupCommand);
}
if (ShutdownRequestPending)
{
diff --git a/src/backend/postmaster/pgarch.c b/src/backend/postmaster/pgarch.cindex 8ecdb9ca23..8e91f2d70f 100644--- a/src/backend/postmaster/pgarch.c+++ b/src/backend/postmaster/pgarch.c@@ -831,11 +831,8 @@ LoadArchiveLibrary(void)
{
ArchiveModuleInit archive_init;
- if (XLogArchiveLibrary[0] != '\0' && XLogArchiveCommand[0] != '\0')- ereport(ERROR,- (errcode(ERRCODE_INVALID_PARAMETER_VALUE),- errmsg("both archive_command and archive_library set"),- errdetail("Only one of archive_command, archive_library may be set.")));+ CheckMutuallyExclusiveGUCs(XLogArchiveLibrary, "archive_library",+ XLogArchiveCommand, "archive_command");
memset(&ArchiveContext, 0, sizeof(ArchiveModuleCallbacks));
diff --git a/src/backend/postmaster/startup.c b/src/backend/postmaster/startup.cindex 8786186898..f9ff2b5583 100644--- a/src/backend/postmaster/startup.c+++ b/src/backend/postmaster/startup.c@@ -20,6 +20,7 @@
#include "postgres.h"
#include "access/xlog.h"
+#include "access/xlogarchive.h"
#include "access/xlogrecovery.h"
#include "access/xlogutils.h"
#include "libpq/pqsignal.h"
@@ -133,13 +134,17 @@ StartupProcShutdownHandler(SIGNAL_ARGS)
* Re-read the config file.
*
* If one of the critical walreceiver options has changed, flag xlog.c
- * to restart it.+ * to restart it. Also, check for invalid combinations of the command/library+ * parameters and reload the recovery callbacks if necessary.
*/
static void
StartupRereadConfig(void)
{
char *conninfo = pstrdup(PrimaryConnInfo);
char *slotname = pstrdup(PrimarySlotName);
+ char *prevRestoreLibrary = pstrdup(restoreLibrary);+ char *prevRestoreCommand = pstrdup(recoveryRestoreCommand);+ char *prevRecoveryEndCommand = pstrdup(recoveryEndCommand);
bool tempSlot = wal_receiver_create_temp_slot;
bool conninfoChanged;
bool slotnameChanged;
@@ -161,6 +166,22 @@ StartupRereadConfig(void)
if (conninfoChanged || slotnameChanged || tempSlotChanged)
StartupRequestWalReceiverRestart();
++ CheckMutuallyExclusiveGUCs(restoreLibrary, "restore_library",+ recoveryRestoreCommand, "restore_command");+ CheckMutuallyExclusiveGUCs(restoreLibrary, "restore_library",+ recoveryEndCommand, "recovery_end_command");+ if (strcmp(prevRestoreLibrary, restoreLibrary) != 0 ||+ strcmp(prevRestoreCommand, recoveryRestoreCommand) != 0 ||+ strcmp(prevRecoveryEndCommand, recoveryEndCommand) != 0)+ {+ call_recovery_module_shutdown_cb(0, (Datum) 0);+ LoadRecoveryCallbacks();+ }++ pfree(prevRestoreLibrary);+ pfree(prevRestoreCommand);+ pfree(prevRecoveryEndCommand);
}
/* Handle various signals that might be sent to the startup process */
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.cindex d52069f446..7858e9a649 100644--- a/src/backend/utils/misc/guc.c+++ b/src/backend/utils/misc/guc.c@@ -6880,3 +6880,17 @@ call_enum_check_hook(struct config_enum *conf, int *newval, void **extra,
return true;
}
++/*+ * ERROR if both parameters are set.+ */+void+CheckMutuallyExclusiveGUCs(const char *p1val, const char *p1name,+ const char *p2val, const char *p2name)+{+ if (p1val[0] != '\0' && p2val[0] != '\0')+ ereport(ERROR,+ (errcode(ERRCODE_INVALID_PARAMETER_VALUE),+ errmsg("both %s and %s set", p1name, p2name),+ errdetail("Only one of %s, %s may be set.", p1name, p2name)));+}diff --git a/src/backend/utils/misc/guc_tables.c b/src/backend/utils/misc/guc_tables.cindex 5025e80f89..a8a516b0c6 100644--- a/src/backend/utils/misc/guc_tables.c+++ b/src/backend/utils/misc/guc_tables.c@@ -3776,6 +3776,16 @@ struct config_string ConfigureNamesString[] =
NULL, NULL, NULL
},
+ {+ {"restore_library", PGC_SIGHUP, WAL_ARCHIVE_RECOVERY,+ gettext_noop("Sets the library that will be called for recovery actions."),+ NULL+ },+ &restoreLibrary,+ "",+ NULL, NULL, NULL+ },+
{
{"archive_cleanup_command", PGC_SIGHUP, WAL_ARCHIVE_RECOVERY,
gettext_noop("Sets the shell command that will be executed at every restart point."),
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sampleindex 4cceda4162..38fb3e0823 100644--- a/src/backend/utils/misc/postgresql.conf.sample+++ b/src/backend/utils/misc/postgresql.conf.sample@@ -269,6 +269,7 @@
# placeholders: %p = path of file to restore
# %f = file name only
# e.g. 'cp /mnt/server/archivedir/%f %p'
+#restore_library = '' # library to use for recovery actions
#archive_cleanup_command = '' # command to execute at every restartpoint
#recovery_end_command = '' # command to execute at completion of recovery
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.hindex 59fc7bc105..756f0898b5 100644--- a/src/include/access/xlog_internal.h+++ b/src/include/access/xlog_internal.h@@ -400,5 +400,6 @@ extern PGDLLIMPORT bool ArchiveRecoveryRequested;
extern PGDLLIMPORT bool InArchiveRecovery;
extern PGDLLIMPORT bool StandbyMode;
extern PGDLLIMPORT char *recoveryRestoreCommand;
+extern PGDLLIMPORT char *restoreLibrary;
#endif /* XLOG_INTERNAL_H */
diff --git a/src/include/access/xlogarchive.h b/src/include/access/xlogarchive.hindex 299304703e..71c9b88165 100644--- a/src/include/access/xlogarchive.h+++ b/src/include/access/xlogarchive.h@@ -30,9 +30,45 @@ extern bool XLogArchiveIsReady(const char *xlog);
extern bool XLogArchiveIsReadyOrDone(const char *xlog);
extern void XLogArchiveCleanup(const char *xlog);
-extern bool shell_restore(const char *file, const char *path,- const char *lastRestartPointFileName);-extern void shell_archive_cleanup(const char *lastRestartPointFileName);-extern void shell_recovery_end(const char *lastRestartPointFileName);+/*+ * Recovery module callbacks+ *+ * These callback functions should be defined by recovery libraries and+ * returned via _PG_recovery_module_init(). For more information about the+ * purpose of each callback, refer to the recovery modules documentation.+ */+typedef bool (*RecoveryRestoreCB) (const char *file, const char *path,+ const char *lastRestartPointFileName);+typedef void (*RecoveryArchiveCleanupCB) (const char *lastRestartPointFileName);+typedef void (*RecoveryEndCB) (const char *lastRestartPointFileName);+typedef void (*RecoveryShutdownCB) (void);++typedef struct RecoveryModuleCallbacks+{+ RecoveryRestoreCB restore_cb;+ RecoveryArchiveCleanupCB archive_cleanup_cb;+ RecoveryEndCB recovery_end_cb;+ RecoveryShutdownCB shutdown_cb;+} RecoveryModuleCallbacks;++extern RecoveryModuleCallbacks RecoveryContext;++/*+ * Type of the shared library symbol _PG_recovery_module_init that is looked up+ * when loading a recovery library.+ */+typedef void (*RecoveryModuleInit) (RecoveryModuleCallbacks *cb);++extern PGDLLEXPORT void _PG_recovery_module_init(RecoveryModuleCallbacks *cb);++extern void LoadRecoveryCallbacks(void);+extern void call_recovery_module_shutdown_cb(int code, Datum arg);++/*+ * Since the logic for recovery via a shell command is in the core server and+ * does not need to be loaded via a shared library, it has a special+ * initialization function.+ */+extern void shell_restore_init(RecoveryModuleCallbacks *cb);
#endif /* XLOG_ARCHIVE_H */
diff --git a/src/include/access/xlogrecovery.h b/src/include/access/xlogrecovery.hindex 47c29350f5..35d1d09374 100644--- a/src/include/access/xlogrecovery.h+++ b/src/include/access/xlogrecovery.h@@ -55,6 +55,7 @@ extern PGDLLIMPORT int recovery_min_apply_delay;
extern PGDLLIMPORT char *PrimaryConnInfo;
extern PGDLLIMPORT char *PrimarySlotName;
extern PGDLLIMPORT char *recoveryRestoreCommand;
+extern PGDLLIMPORT char *restoreLibrary;
extern PGDLLIMPORT char *recoveryEndCommand;
extern PGDLLIMPORT char *archiveCleanupCommand;
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.hindex ba89d013e6..947597247f 100644--- a/src/include/utils/guc.h+++ b/src/include/utils/guc.h@@ -404,6 +404,8 @@ extern void *guc_malloc(int elevel, size_t size);
extern pg_nodiscard void *guc_realloc(int elevel, void *old, size_t size);
extern char *guc_strdup(int elevel, const char *src);
extern void guc_free(void *ptr);
+extern void CheckMutuallyExclusiveGUCs(const char *p1val, const char *p1name,+ const char *p2val, const char *p2name);
#ifdef EXEC_BACKEND
extern void write_nondefault_variables(GucContext context);
--
2.25.1
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To: pgsql-hackers@postgresql.org
Cc: nathandbossart@gmail.com, michael@paquier.xyz, andres@anarazel.de
Subject: Re: recovery modules
In-Reply-To: <20230117182356.GA3015764@nathanxps13>
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