mirror of https://github.com/postgres/postgres
The code specific to the execution of archive_cleanup_command, recovery_end_command and restore_command is moved to a new file named shell_restore.c. The code is split into three functions: - shell_restore(), that attempts the execution of a shell-based restore_command. - shell_archive_cleanup(), for archive_cleanup_command. - shell_recovery_end(), for recovery_end_command. This introduces no functional changes, with failure patterns and logs generated in consequence being the same as before (one case actually generates one less DEBUG2 message "could not restore" when a restore command succeeds but the follow-up stat() to check the size fails, but that only matters with a elevel high enough). This is preparatory work for allowing recovery modules, a facility similar to archive modules, with callbacks shaped similarly to the functions introduced here. Author: Nathan Bossart Reviewed-by: Andres Freund, Michael Paquier Discussion: https://postgr.es/m/20221227192449.GA3672473@nathanxps13pull/113/head
Michael Paquier
3 years ago
parent
02d3448f4f
commit
9a740f81eb
@ -0,0 +1,175 @@ |
||||
/*-------------------------------------------------------------------------
|
||||
* |
||||
* shell_restore.c |
||||
* 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). |
||||
* |
||||
* Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group |
||||
* Portions Copyright (c) 1994, Regents of the University of California |
||||
* |
||||
* src/backend/access/transam/shell_restore.c |
||||
* |
||||
*------------------------------------------------------------------------- |
||||
*/ |
||||
|
||||
#include "postgres.h" |
||||
|
||||
#include <signal.h> |
||||
|
||||
#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, |
||||
const char *commandName, |
||||
bool failOnSignal, |
||||
uint32 wait_event_info, |
||||
const char *lastRestartPointFileName); |
||||
|
||||
/*
|
||||
* Attempt to execute a shell-based restore command. |
||||
* |
||||
* Returns true if the command has succeeded, false otherwise. |
||||
*/ |
||||
bool |
||||
shell_restore(const char *file, const char *path, |
||||
const char *lastRestartPointFileName) |
||||
{ |
||||
char *cmd; |
||||
int rc; |
||||
|
||||
/* 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); |
||||
|
||||
/*
|
||||
* Remember, we rollforward UNTIL the restore fails so failure here is |
||||
* just part of the process... that makes it difficult to determine |
||||
* whether the restore failed because there isn't an archive to restore, |
||||
* or because the administrator has specified the restore program |
||||
* incorrectly. We have to assume the former. |
||||
* |
||||
* However, if the failure was due to any sort of signal, it's best to |
||||
* punt and abort recovery. (If we "return false" here, upper levels will |
||||
* assume that recovery is complete and start up the database!) It's |
||||
* essential to abort on child SIGINT and SIGQUIT, because per spec |
||||
* system() ignores SIGINT and SIGQUIT while waiting; if we see one of |
||||
* those it's a good bet we should have gotten it too. |
||||
* |
||||
* On SIGTERM, assume we have received a fast shutdown request, and exit |
||||
* cleanly. It's pure chance whether we receive the SIGTERM first, or the |
||||
* child process. If we receive it first, the signal handler will call |
||||
* proc_exit, otherwise we do it here. If we or the child process received |
||||
* SIGTERM for any other reason than a fast shutdown request, postmaster |
||||
* will perform an immediate shutdown when it sees us exiting |
||||
* unexpectedly. |
||||
* |
||||
* 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)))); |
||||
} |
||||
|
||||
return (rc == 0); |
||||
} |
||||
|
||||
/*
|
||||
* Attempt to execute a shell-based archive cleanup command. |
||||
*/ |
||||
void |
||||
shell_archive_cleanup(const char *lastRestartPointFileName) |
||||
{ |
||||
ExecuteRecoveryCommand(archiveCleanupCommand, "archive_cleanup_command", |
||||
false, WAIT_EVENT_ARCHIVE_CLEANUP_COMMAND, |
||||
lastRestartPointFileName); |
||||
} |
||||
|
||||
/*
|
||||
* Attempt to execute a shell-based end-of-recovery command. |
||||
*/ |
||||
void |
||||
shell_recovery_end(const char *lastRestartPointFileName) |
||||
{ |
||||
ExecuteRecoveryCommand(recoveryEndCommand, "recovery_end_command", true, |
||||
WAIT_EVENT_RECOVERY_END_COMMAND, |
||||
lastRestartPointFileName); |
||||
} |
||||
|
||||
/*
|
||||
* Attempt to execute an external shell command during recovery. |
||||
* |
||||
* '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. |
||||
* |
||||
* This is currently used for recovery_end_command and archive_cleanup_command. |
||||
*/ |
||||
static void |
||||
ExecuteRecoveryCommand(const char *command, const char *commandName, |
||||
bool failOnSignal, uint32 wait_event_info, |
||||
const char *lastRestartPointFileName) |
||||
{ |
||||
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))); |
||||
|
||||
/*
|
||||
* execute the constructed command |
||||
*/ |
||||
fflush(NULL); |
||||
pgstat_report_wait_start(wait_event_info); |
||||
rc = system(xlogRecoveryCmd); |
||||
pgstat_report_wait_end(); |
||||
|
||||
pfree(xlogRecoveryCmd); |
||||
|
||||
if (rc != 0) |
||||
{ |
||||
/*
|
||||
* 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, |
||||
/*------
|
||||
translator: First %s represents a postgresql.conf parameter name like |
||||
"recovery_end_command", the 2nd is the value of that parameter, the |
||||
third an already translated error message. */ |
||||
(errmsg("%s \"%s\": %s", commandName, |
||||
command, wait_result_to_str(rc)))); |
||||
} |
||||
} |
||||
Loading…
Reference in new issue