database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-26 01:22:12 +03:00
Code Activity

Allow archiving via loadable modules.

Browse Source 
Running a shell command for each file to be archived has a lot of
overhead and may not offer as much error checking as you want, or the
exact semantics that you want. So, offer the option to call a loadable
module for each file to be archived, rather than running a shell command.

Also, add a 'basic_archive' contrib module as an example implementation
that archives to a local directory.

Nathan Bossart, with a little bit of kibitzing by me.

Discussion: http://postgr.es/m/20220202224433.GA1036711@nathanxps13
This commit is contained in:
Robert Haas
2022-02-03 13:57:27 -05:00
parent 7c1aead6cb
commit 5ef1eefd76
26 changed files with 941 additions and 67 deletions
Download Patch File Download Diff File Expand all files Collapse all files

116
src/backend/postmaster/pgarch.c
View File

@ -89,6 +89,8 @@ typedef struct PgArchData
slock_t arch_lck;
} PgArchData;
char *XLogArchiveLibrary = "";
/* ----------
* Local data
@ -96,6 +98,8 @@ typedef struct PgArchData
*/
static time_t last_sigterm_time = 0;
static PgArchData *PgArch = NULL;
static ArchiveModuleCallbacks ArchiveContext;
/*
* Stuff for tracking multiple files to archive from each scan of
@ -140,6 +144,8 @@ static void pgarch_archiveDone(char *xlog);
static void pgarch_die(int code, Datum arg);
static void HandlePgArchInterrupts(void);
static int ready_file_comparator(Datum a, Datum b, void *arg);
static void LoadArchiveLibrary(void);
static void call_archive_module_shutdown_callback(int code, Datum arg);
/* Report shared memory space needed by PgArchShmemInit */
Size
@ -244,7 +250,16 @@ PgArchiverMain(void)
arch_files->arch_heap = binaryheap_allocate(NUM_FILES_PER_DIRECTORY_SCAN,
ready_file_comparator, NULL);
pgarch_MainLoop();
/* Load the archive_library. */
LoadArchiveLibrary();
PG_ENSURE_ERROR_CLEANUP(call_archive_module_shutdown_callback, 0);
{
pgarch_MainLoop();
}
PG_END_ENSURE_ERROR_CLEANUP(call_archive_module_shutdown_callback, 0);
call_archive_module_shutdown_callback(0, 0);
proc_exit(0);
}
@ -407,11 +422,12 @@ pgarch_ArchiverCopyLoop(void)
*/
HandlePgArchInterrupts();
/* can't do anything if no command ... */
if (!XLogArchiveCommandSet())
/* can't do anything if not configured ... */
if (ArchiveContext.check_configured_cb != NULL &&
!ArchiveContext.check_configured_cb())
{
ereport(WARNING,
(errmsg("archive_mode enabled, yet archive_command is not set")));
(errmsg("archive_mode enabled, yet archiving is not configured")));
return;
}
@ -492,7 +508,7 @@ pgarch_ArchiverCopyLoop(void)
/*
* pgarch_archiveXlog
*
* Invokes system(3) to copy one archive file to wherever it should go
* Invokes archive_file_cb to copy one archive file to wherever it should go
*
* Returns true if successful
*/
@ -509,7 +525,7 @@ pgarch_archiveXlog(char *xlog)
snprintf(activitymsg, sizeof(activitymsg), "archiving %s", xlog);
set_ps_display(activitymsg);
ret = shell_archive_file(xlog, pathname);
ret = ArchiveContext.archive_file_cb(xlog, pathname);
if (ret)
snprintf(activitymsg, sizeof(activitymsg), "last was %s", xlog);
else
@ -759,13 +775,89 @@ HandlePgArchInterrupts(void)
if (ProcSignalBarrierPending)
ProcessProcSignalBarrier();
if (ConfigReloadPending)
{
ConfigReloadPending = false;
ProcessConfigFile(PGC_SIGHUP);
}
/* Perform logging of memory contexts of this process */
if (LogMemoryContextPending)
ProcessLogMemoryContextInterrupt();
if (ConfigReloadPending)
{
char *archiveLib = pstrdup(XLogArchiveLibrary);
bool archiveLibChanged;
ConfigReloadPending = false;
ProcessConfigFile(PGC_SIGHUP);
archiveLibChanged = strcmp(XLogArchiveLibrary, archiveLib) != 0;
pfree(archiveLib);
if (archiveLibChanged)
{
/*
* Call the currently loaded archive module's shutdown callback, if
* one is defined.
*/
call_archive_module_shutdown_callback(0, 0);
/*
* Ideally, we would simply unload the previous archive module and
* load the new one, but there is presently no mechanism for
* unloading a library (see the comment above
* internal_unload_library()). To deal with this, we simply restart
* the archiver. The new archive module will be loaded when the new
* archiver process starts up.
*/
ereport(LOG,
(errmsg("restarting archiver process because value of "
"\"archive_library\" was changed")));
proc_exit(0);
}
}
}
/*
* LoadArchiveLibrary
*
* Loads the archiving callbacks into our local ArchiveContext.
*/
static void
LoadArchiveLibrary(void)
{
ArchiveModuleInit archive_init;
memset(&ArchiveContext, 0, sizeof(ArchiveModuleCallbacks));
/*
* If shell archiving is enabled, use our special initialization
* function. Otherwise, load the library and call its
* _PG_archive_module_init().
*/
if (XLogArchiveLibrary[0] == '\0')
archive_init = shell_archive_init;
else
archive_init = (ArchiveModuleInit)
load_external_function(XLogArchiveLibrary,
"_PG_archive_module_init", false, NULL);
if (archive_init == NULL)
ereport(ERROR,
(errmsg("archive modules have to declare the _PG_archive_module_init symbol")));
(*archive_init) (&ArchiveContext);
if (ArchiveContext.archive_file_cb == NULL)
ereport(ERROR,
(errmsg("archive modules must register an archive callback")));
}
/*
* call_archive_module_shutdown_callback
*
* Calls the loaded archive module's shutdown callback, if one is defined.
*/
static void
call_archive_module_shutdown_callback(int code, Datum arg)
{
if (ArchiveContext.shutdown_cb != NULL)
ArchiveContext.shutdown_cb();
}