Make WAL-related utilities handle .partial WAL files properly.

Commit de76884 changed an archive recovery so that the last WAL
segment with old timeline was renamed with suffix .partial. It should
have updated WAL-related utilities so that they can handle such
.paritial WAL files, but we forgot that.

This patch changes pg_archivecleanup so that it can clean up even
archived WAL files with .partial suffix. Also it allows us to specify
.partial WAL file name as the command-line argument "oldestkeptwalfile".

This patch also changes pg_resetxlog so that it can remove .partial
WAL files in pg_xlog directory.

pg_xlogdump cannot handle .partial WAL files. Per discussion,
we decided only to document that limitation instead of adding the fix.
Because a user can easily work around the limitation (i.e., just remove
.partial suffix from the file name) and the fix seems complicated for
very narrow use case.

Back-patch to 9.5 where the problem existed.

Review by Michael Paquier.
Discussion: http://www.postgresql.org/message-id/CAHGQGwGxMKnVHGgTfiig2Bt_2djec0in3-DLJmtg7+nEiidFdQ@mail.gmail.com

2 files changed, 33 insertions, 8 deletions

diff --git a/src/bin/pg_archivecleanup/pg_archivecleanup.c b/src/bin/pg_archivecleanup/pg_archivecleanup.c
index 579a9bb8430..c5569f32a33 100644
--- a/src/bin/pg_archivecleanup/pg_archivecleanup.c
+++ b/src/bin/pg_archivecleanup/pg_archivecleanup.c
@@ -125,7 +125,7 @@ CleanupPriorWALFiles(void)
 			 * file. Note that this means files are not removed in the order
 			 * they were originally written, in case this worries you.
 			 */
-			if (IsXLogFileName(walfile) &&
+			if ((IsXLogFileName(walfile) || IsPartialXLogFileName(walfile)) &&
 				strcmp(walfile + 8, exclusiveCleanupFileName + 8) < 0)
 			{
 				/*
@@ -181,7 +181,7 @@ CleanupPriorWALFiles(void)
  * SetWALFileNameForCleanup()
  *
  *	  Set the earliest WAL filename that we want to keep on the archive
- *	  and decide whether we need_cleanup
+ *	  and decide whether we need cleanup
  */
 static void
 SetWALFileNameForCleanup(void)
@@ -192,9 +192,10 @@ SetWALFileNameForCleanup(void)
 
 	/*
 	 * If restartWALFileName is a WAL file name then just use it directly. If
-	 * restartWALFileName is a .backup filename, make sure we use the prefix
-	 * of the filename, otherwise we will remove wrong files since
-	 * 000000010000000000000010.00000020.backup is after
+	 * restartWALFileName is a .partial or .backup filename, make sure we use
+	 * the prefix of the filename, otherwise we will remove wrong files since
+	 * 000000010000000000000010.partial and
+	 * 000000010000000000000010.00000020.backup are after
 	 * 000000010000000000000010.
 	 */
 	if (IsXLogFileName(restartWALFileName))
@@ -202,6 +203,26 @@ SetWALFileNameForCleanup(void)
 		strcpy(exclusiveCleanupFileName, restartWALFileName);
 		fnameOK = true;
 	}
+	else if (IsPartialXLogFileName(restartWALFileName))
+	{
+		int			args;
+		uint32		tli = 1,
+					log = 0,
+					seg = 0;
+
+		args = sscanf(restartWALFileName, "%08X%08X%08X.partial",
+					  &tli, &log, &seg);
+		if (args == 3)
+		{
+			fnameOK = true;
+
+			/*
+			 * Use just the prefix of the filename, ignore everything after
+			 * first period
+			 */
+			XLogFileNameById(exclusiveCleanupFileName, tli, log, seg);
+		}
+	}
 	else if (IsBackupHistoryFileName(restartWALFileName))
 	{
 		int			args;
diff --git a/src/bin/pg_resetxlog/pg_resetxlog.c b/src/bin/pg_resetxlog/pg_resetxlog.c
index e19a72b4c16..e7e8059a38d 100644
--- a/src/bin/pg_resetxlog/pg_resetxlog.c
+++ b/src/bin/pg_resetxlog/pg_resetxlog.c
@@ -906,7 +906,8 @@ FindEndOfXLOG(void)
 
 	while (errno = 0, (xlde = readdir(xldir)) != NULL)
 	{
-		if (IsXLogFileName(xlde->d_name))
+		if (IsXLogFileName(xlde->d_name) ||
+			IsPartialXLogFileName(xlde->d_name))
 		{
 			unsigned int tli,
 						log,
@@ -976,7 +977,8 @@ KillExistingXLOG(void)
 
 	while (errno = 0, (xlde = readdir(xldir)) != NULL)
 	{
-		if (IsXLogFileName(xlde->d_name))
+		if (IsXLogFileName(xlde->d_name) ||
+			IsPartialXLogFileName(xlde->d_name))
 		{
 			snprintf(path, MAXPGPATH, "%s/%s", XLOGDIR, xlde->d_name);
 			if (unlink(path) < 0)
@@ -1028,7 +1030,9 @@ KillExistingArchiveStatus(void)
 	{
 		if (strspn(xlde->d_name, "0123456789ABCDEF") == XLOG_FNAME_LEN &&
 			(strcmp(xlde->d_name + XLOG_FNAME_LEN, ".ready") == 0 ||
-			 strcmp(xlde->d_name + XLOG_FNAME_LEN, ".done") == 0))
+			 strcmp(xlde->d_name + XLOG_FNAME_LEN, ".done") == 0 ||
+			 strcmp(xlde->d_name + XLOG_FNAME_LEN, ".partial.ready") == 0 ||
+			 strcmp(xlde->d_name + XLOG_FNAME_LEN, ".partial.done") == 0))
 		{
 			snprintf(path, MAXPGPATH, "%s/%s", ARCHSTATDIR, xlde->d_name);
 			if (unlink(path) < 0)