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Prevent WAL files created by pg_basebackup -x/X from being archived again.

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WAL (and timeline history) files created by pg_basebackup did not
maintain the new base backup's archive status. That's currently not a
problem if the new node is used as a standby - but if that node is
promoted all still existing files can get archived again.  With a high
wal_keep_segment settings that can happen a significant time later -
which is quite confusing.

Change both the backend (for the -x/-X fetch case) and pg_basebackup
(for -X stream) itself to always mark WAL/timeline files included in
the base backup as .done. That's in line with walreceiver.c doing so.

The verbosity of the pg_basebackup changes show pretty clearly that it
needs some refactoring, but that'd result in not be backpatchable
changes.

Backpatch to 9.1 where pg_basebackup was introduced.

Discussion: 20141205002854.GE21964@awork2.anarazel.de
This commit is contained in:
Andres Freund
2015-01-03 20:51:52 +01:00
parent ccb161b66a
commit 2c0a485896
5 changed files with 128 additions and 33 deletions
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35
src/bin/pg_basebackup/pg_basebackup.c
View File

@@ -25,6 +25,7 @@
#include <zlib.h>
#endif
#include "common/string.h"
#include "getopt_long.h"
#include "libpq-fe.h"
#include "pqexpbuffer.h"
@@ -370,7 +371,7 @@ LogStreamerMain(logstreamer_param *param)
if (!ReceiveXlogStream(param->bgconn, param->startptr, param->timeline,
param->sysidentifier, param->xlogdir,
reached_end_position, standby_message_timeout,
NULL, false))
NULL, false, true))
/*
* Any errors will already have been reported in the function process,
@@ -394,6 +395,7 @@ StartLogStreamer(char *startpos, uint32 timeline, char *sysidentifier)
logstreamer_param *param;
uint32 hi,
lo;
char statusdir[MAXPGPATH];
param = pg_malloc0(sizeof(logstreamer_param));
param->timeline = timeline;
@@ -428,13 +430,23 @@ StartLogStreamer(char *startpos, uint32 timeline, char *sysidentifier)
/* Error message already written in GetConnection() */
exit(1);
/*
* Always in plain format, so we can write to basedir/pg_xlog. But the
* directory entry in the tar file may arrive later, so make sure it's
* created before we start.
*/
snprintf(param->xlogdir, sizeof(param->xlogdir), "%s/pg_xlog", basedir);
verify_dir_is_empty_or_create(param->xlogdir);
/*
* Create pg_xlog/archive_status (and thus pg_xlog) so we can can write to
* basedir/pg_xlog as the directory entry in the tar file may arrive
* later.
*/
snprintf(statusdir, sizeof(statusdir), "%s/pg_xlog/archive_status",
basedir);
if (pg_mkdir_p(statusdir, S_IRWXU) != 0 && errno != EEXIST)
{
fprintf(stderr,
_("%s: could not create directory \"%s\": %s\n"),
progname, statusdir, strerror(errno));
disconnect_and_exit(1);
}
/*
* Start a child process and tell it to start streaming. On Unix, this is
@@ -1236,11 +1248,12 @@ ReceiveAndUnpackTarFile(PGconn *conn, PGresult *res, int rownum)
* by the wal receiver process. Also, when transaction
* log directory location was specified, pg_xlog has
* already been created as a symbolic link before
* starting the actual backup. So just ignore failure
* on them.
* starting the actual backup. So just ignore creation
* failures on related directories.
*/
if ((!streamwal && (strcmp(xlog_dir, "") == 0))
|| strcmp(filename + strlen(filename) - 8, "/pg_xlog") != 0)
if (!((pg_str_endswith(filename, "/pg_xlog") ||
pg_str_endswith(filename, "/archive_status")) &&
errno == EEXIST))
{
fprintf(stderr,
_("%s: could not create directory \"%s\": %s\n"),