code cleanup for 22cb8c6

Author: alubennikova

src/backup.c

@@ -1332,21 +1332,20 @@ pg_ptrack_get_and_clear(Oid tablespace_oid, Oid db_oid, Oid rel_filenode,
 						   2, (const char **)params);
 
 		if (PQnfields(res) != 1)
-		elog(ERROR, "cannot get ptrack file from pg_global tablespace and relation oid %u",
+			elog(ERROR, "cannot get ptrack file from pg_global tablespace and relation oid %u",
 			 rel_filenode);
 	}
 
 	val = PQgetvalue(res, 0, 0);
 
+	/* TODO Now pg_ptrack_get_and_clear() returns bytea ending with \x.
+	 * It should be fixed in future ptrack releases, but till then we
+	 * can parse it.
+	 */
 	if (strcmp("x", val+1) == 0)
 	{
-		/*
-		 * Ptrack file is missing!
-		 * TODO COMPARE FILE CHECKSUMM to this file version from previous backup
-		 * if they are equal, skip this file
-		 *
-		 */
-		return false;
+		/* Ptrack file is missing */
+		return NULL;
 	}
 
 	result = (char *) PQunescapeBytea((unsigned char *) PQgetvalue(res, 0, 0),
@@ -2360,7 +2359,6 @@ make_pagemap_from_ptrack(parray *files)
 	size_t		i;
 	Oid dbOid_with_ptrack_init = 0;
 	Oid tblspcOid_with_ptrack_init = 0;
-	bool ignore_ptrack_for_db = false;
 	char	   *ptrack_nonparsed = NULL;
 	size_t		ptrack_nonparsed_size = 0;
 
@@ -2376,7 +2374,6 @@ make_pagemap_from_ptrack(parray *files)
 		if (file->is_database)
 		{
 			char *filename = strrchr(file->path, '/');
-			ignore_ptrack_for_db = false;
 
 			Assert(filename != NULL);
 			filename++;
@@ -2390,7 +2387,6 @@ make_pagemap_from_ptrack(parray *files)
 			if ((file->tblspcOid == GLOBALTABLESPACE_OID) ||
 				pg_ptrack_get_and_clear_db(file->dbOid, file->tblspcOid))
 			{
-				ignore_ptrack_for_db = true;
 				dbOid_with_ptrack_init = file->dbOid;
 				tblspcOid_with_ptrack_init = file->tblspcOid;
 			}
@@ -2400,13 +2396,12 @@ make_pagemap_from_ptrack(parray *files)
 		{
 			if (file->tblspcOid == tblspcOid_with_ptrack_init
 					&& file->dbOid == dbOid_with_ptrack_init)
-				{
-					/* ignore ptrack */
-					Assert (ignore_ptrack_for_db);
-					elog(VERBOSE, "Ignoring ptrack because of ptrack_init for file: %s", file->path);
-					file->pagemap.bitmapsize = -1;
-					continue;
-				}
+			{
+				/* ignore ptrack if ptrack_init exists */
+				elog(VERBOSE, "Ignoring ptrack because of ptrack_init for file: %s", file->path);
+				file->pagemap.bitmapsize = PageBitmapIsAbsent;
+				continue;
+			}
 
 			/* get ptrack bitmap once for all segments of the file */
 			if (file->segno == 0)
@@ -2419,34 +2414,24 @@ make_pagemap_from_ptrack(parray *files)
 											   file->relOid, &ptrack_nonparsed_size);
 			}
 
-			/* If ptrack file is missing, then copy entire file */
-			if (!ptrack_nonparsed)
-				{
-					elog(VERBOSE, "Ptrack is missing for file: %s", file->path);
-					file->pagemap.bitmapsize = -1;
-					continue;
-				}
-
 			if (ptrack_nonparsed != NULL)
 			{
 				/*
-				* TODO When do we cut VARHDR from ptrack_nonparsed?
-				*  pg_ptrack_get_and_clear returns ptrack with VARHDR cutted out.
-				* Compute the beginning of the ptrack map related to this segment
-				*
-				* HEAPBLOCKS_PER_BYTE. Number of heap pages one ptrack byte can track: 8
-				* RELSEG_SIZE. Number of Pages per segment: 131072
-				* RELSEG_SIZE/HEAPBLOCKS_PER_BYTE. number of bytes from ptrack file needed
-				*  to keep track on one relsegment: 16384
-				*/
+				 * pg_ptrack_get_and_clear() returns ptrack with VARHDR cutted out.
+				 * Compute the beginning of the ptrack map related to this segment
+				 *
+				 * HEAPBLOCKS_PER_BYTE. Number of heap pages one ptrack byte can track: 8
+				 * RELSEG_SIZE. Number of Pages per segment: 131072
+				 * RELSEG_SIZE/HEAPBLOCKS_PER_BYTE. number of bytes in ptrack file needed
+				 * to keep track on one relsegment: 16384
+				 */
 				start_addr = (RELSEG_SIZE/HEAPBLOCKS_PER_BYTE)*file->segno;
 
 				if (start_addr + RELSEG_SIZE/HEAPBLOCKS_PER_BYTE > ptrack_nonparsed_size)
 				{
 					file->pagemap.bitmapsize = ptrack_nonparsed_size - start_addr;
 					elog(VERBOSE, "pagemap size: %i", file->pagemap.bitmapsize);
 				}
-
 				else
 				{
 					file->pagemap.bitmapsize =	RELSEG_SIZE/HEAPBLOCKS_PER_BYTE;
@@ -2457,7 +2442,18 @@ make_pagemap_from_ptrack(parray *files)
 				memcpy(file->pagemap.bitmap, ptrack_nonparsed+start_addr, file->pagemap.bitmapsize);
 			}
 			else
-				elog(ERROR, "Ptrack content should not be empty. File: %s", file->path);
+			{
+				/*
+				 * If ptrack file is missing, try to copy the entire file.
+				 * It can happen in two cases:
+				 * - files were created by commands that bypass buffer manager
+				 * and, correspondingly, ptrack mechanism.
+				 * i.e. CREATE DATABASE
+				 * - target relation was deleted.
+				 */
+				elog(VERBOSE, "Ptrack is missing for file: %s", file->path);
+				file->pagemap.bitmapsize = PageBitmapIsAbsent;
+			}
 		}
 	}
 }

src/data.c

@@ -295,16 +295,26 @@ backup_data_file(const char *from_root, const char *to_root,
 
 	if ((backup_mode == BACKUP_MODE_DIFF_PAGE ||
 		backup_mode == BACKUP_MODE_DIFF_PTRACK) &&
-		file->pagemap.bitmapsize == 0)
+		file->pagemap.bitmapsize == PageBitmapIsEmpty)
 	{
 		/*
 		 * There are no changed blocks since last backup. We want make
 		 * incremental backup, so we should exit.
 		 */
-		elog(VERBOSE, "Skipping file because it didn`t changed: %s", file->path);
+		elog(VERBOSE, "Skipping the file because it didn`t changed: %s", file->path);
 		return false;
 	}
 
+	if ((backup_mode == BACKUP_MODE_DIFF_PAGE ||
+		backup_mode == BACKUP_MODE_DIFF_PTRACK) &&
+		file->pagemap.bitmapsize == PageBitmapIsAbsent)
+	{
+		/*
+		 * TODO COMPARE FILE CHECKSUMM to this file version from previous backup
+		 * if they are equal, skip this file
+		 */
+	}
+
 	/* reset size summary */
 	file->read_size = 0;
 	file->write_size = 0;
@@ -358,7 +368,8 @@ backup_data_file(const char *from_root, const char *to_root,
 	 * Read each page, verify checksum and write it to backup.
 	 * If page map is empty backup all pages of the relation.
 	 */
-	if (file->pagemap.bitmapsize == 0 || file->pagemap.bitmapsize == -1)
+	if (file->pagemap.bitmapsize == PageBitmapIsEmpty
+		|| file->pagemap.bitmapsize == PageBitmapIsAbsent)
 	{
 		for (blknum = 0; blknum < nblocks; blknum++)
 		{

src/dir.c

@@ -149,7 +149,7 @@ pgFileInit(const char *path)
 	file->is_datafile = false;
 	file->linked = NULL;
 	file->pagemap.bitmap = NULL;
-	file->pagemap.bitmapsize = 0;
+	file->pagemap.bitmapsize = PageBitmapIsAbsent;
 	file->tblspcOid = 0;
 	file->dbOid = 0;
 	file->relOid = 0;

src/pg_probackup.h

@@ -104,6 +104,10 @@ typedef struct pgFile
 	datapagemap_t pagemap;	/* bitmap of pages updated since previous backup */
 } pgFile;
 
+/* Special values of datapagemap_t bitmapsize */
+#define PageBitmapIsEmpty 0
+#define PageBitmapIsAbsent -1
+
 /* Current state of backup */
 typedef enum BackupStatus
 {