In pg_upgrade, copy fsm, vm, and extent files by checking for file

existence via open(), rather than collecting a directory listing and
looking up matching relfilenode files with sequential scans of the
array.  This speeds up pg_upgrade by 2x for a large number of tables,
e.g. 16k.

Per observation by Ants Aasma.

contrib/pg_upgrade/file.c

@@ -221,61 +221,6 @@ copy_file(const char *srcfile, const char *dstfile, bool force)
 #endif
 
 
-/*
- * load_directory()
- *
- * Read all the file names in the specified directory, and return them as
- * an array of "char *" pointers.  The array address is returned in
- * *namelist, and the function result is the count of file names.
- *
- * To free the result data, free each (char *) array member, then free the
- * namelist array itself.
- */
-int
-load_directory(const char *dirname, char ***namelist)
-{
-	DIR		   *dirdesc;
-	struct dirent *direntry;
-	int			count = 0;
-	int			allocsize = 64;		/* initial array size */
-
-	*namelist = (char **) pg_malloc(allocsize * sizeof(char *));
-
-	if ((dirdesc = opendir(dirname)) == NULL)
-		pg_log(PG_FATAL, "could not open directory \"%s\": %s\n",
-			   dirname, getErrorText(errno));
-
-	while (errno = 0, (direntry = readdir(dirdesc)) != NULL)
-	{
-		if (count >= allocsize)
-		{
-			allocsize *= 2;
-			*namelist = (char **)
-						pg_realloc(*namelist, allocsize * sizeof(char *));
-		}
-
-		(*namelist)[count++] = pg_strdup(direntry->d_name);
-	}
-
-#ifdef WIN32
-	/*
-	 * This fix is in mingw cvs (runtime/mingwex/dirent.c rev 1.4), but not in
-	 * released version
-	 */
-	if (GetLastError() == ERROR_NO_MORE_FILES)
-		errno = 0;
-#endif
-
-	if (errno)
-		pg_log(PG_FATAL, "could not read directory \"%s\": %s\n",
-			   dirname, getErrorText(errno));
-
-	closedir(dirdesc);
-
-	return count;
-}
-
-
 void
 check_hard_link(void)
 {

contrib/pg_upgrade/pg_upgrade.h

@@ -7,7 +7,6 @@
 
 #include <unistd.h>
 #include <assert.h>
-#include <dirent.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 
@@ -366,7 +365,6 @@ const char *setupPageConverter(pageCnvCtx **result);
 typedef void *pageCnvCtx;
 #endif
 
-int			load_directory(const char *dirname, char ***namelist);
 const char *copyAndUpdateFile(pageCnvCtx *pageConverter, const char *src,
 				  const char *dst, bool force);
 const char *linkAndUpdateFile(pageCnvCtx *pageConverter, const char *src,

contrib/pg_upgrade/relfilenode.c

@@ -17,9 +17,8 @@
 
 static void transfer_single_new_db(pageCnvCtx *pageConverter,
 					   FileNameMap *maps, int size);
-static void transfer_relfile(pageCnvCtx *pageConverter,
-				 const char *fromfile, const char *tofile,
-				 const char *nspname, const char *relname);
+static void transfer_relfile(pageCnvCtx *pageConverter, FileNameMap *map,
+							 const char *suffix);
 
 
 /*
@@ -131,55 +130,21 @@ static void
 transfer_single_new_db(pageCnvCtx *pageConverter,
 					   FileNameMap *maps, int size)
 {
-	char		old_dir[MAXPGPATH];
-	char		file_pattern[MAXPGPATH];
-	char		**namelist = NULL;
-	int			numFiles = 0;
 	int			mapnum;
-	int			fileno;
-	bool		vm_crashsafe_change = false;
+	bool		vm_crashsafe_match = true;
 	
-	old_dir[0] = '\0';
-
-	/* Do not copy non-crashsafe vm files for binaries that assume crashsafety */
+	/*
+	 * Do the old and new cluster disagree on the crash-safetiness of the vm
+     * files?  If so, do not copy them.
+     */
 	if (old_cluster.controldata.cat_ver < VISIBILITY_MAP_CRASHSAFE_CAT_VER &&
 		new_cluster.controldata.cat_ver >= VISIBILITY_MAP_CRASHSAFE_CAT_VER)
-		vm_crashsafe_change = true;
+		vm_crashsafe_match = false;
 
 	for (mapnum = 0; mapnum < size; mapnum++)
 	{
-		char		old_file[MAXPGPATH];
-		char		new_file[MAXPGPATH];
-
-		/* Changed tablespaces?  Need a new directory scan? */
-		if (strcmp(maps[mapnum].old_dir, old_dir) != 0)
-		{
-			if (numFiles > 0)
-			{
-				for (fileno = 0; fileno < numFiles; fileno++)
-					pg_free(namelist[fileno]);
-				pg_free(namelist);
-			}
-
-			snprintf(old_dir, sizeof(old_dir), "%s", maps[mapnum].old_dir);
-			numFiles = load_directory(old_dir, &namelist);
-		}
-
-		/* Copying files might take some time, so give feedback. */
-
-		snprintf(old_file, sizeof(old_file), "%s/%u", maps[mapnum].old_dir,
-				 maps[mapnum].old_relfilenode);
-		snprintf(new_file, sizeof(new_file), "%s/%u", maps[mapnum].new_dir,
-				 maps[mapnum].new_relfilenode);
-		pg_log(PG_REPORT, OVERWRITE_MESSAGE, old_file);
-
-		/*
-		 * Copy/link the relation's primary file (segment 0 of main fork)
-		 * to the new cluster
-		 */
-		unlink(new_file);
-		transfer_relfile(pageConverter, old_file, new_file,
-						 maps[mapnum].nspname, maps[mapnum].relname);
+		/* transfer primary file */
+		transfer_relfile(pageConverter, &maps[mapnum], "");
 
 		/* fsm/vm files added in PG 8.4 */
 		if (GET_MAJOR_VERSION(old_cluster.major_version) >= 804)
@@ -187,80 +152,69 @@ transfer_single_new_db(pageCnvCtx *pageConverter,
 			/*
 			 * Copy/link any fsm and vm files, if they exist
 			 */
-			snprintf(file_pattern, sizeof(file_pattern), "%u_",
-					 maps[mapnum].old_relfilenode);
-
-			for (fileno = 0; fileno < numFiles; fileno++)
-			{
-				char	   *vm_offset = strstr(namelist[fileno], "_vm");
-				bool		is_vm_file = false;
-
-				/* Is a visibility map file? (name ends with _vm) */
-				if (vm_offset && strlen(vm_offset) == strlen("_vm"))
-					is_vm_file = true;
-
-				if (strncmp(namelist[fileno], file_pattern,
-							strlen(file_pattern)) == 0 &&
-					(!is_vm_file || !vm_crashsafe_change))
-				{
-					snprintf(old_file, sizeof(old_file), "%s/%s", maps[mapnum].old_dir,
-							 namelist[fileno]);
-					snprintf(new_file, sizeof(new_file), "%s/%u%s", maps[mapnum].new_dir,
-							 maps[mapnum].new_relfilenode, strchr(namelist[fileno], '_'));
-
-					unlink(new_file);
-					transfer_relfile(pageConverter, old_file, new_file,
-								 maps[mapnum].nspname, maps[mapnum].relname);
-				}
+			transfer_relfile(pageConverter, &maps[mapnum], "_fsm");
+			if (vm_crashsafe_match)
+				transfer_relfile(pageConverter, &maps[mapnum], "_vm");
 		}
 	}
+}
+
+
+/*
+ * transfer_relfile()
+ *
+ * Copy or link file from old cluster to new one.
+ */
+static void
+transfer_relfile(pageCnvCtx *pageConverter, FileNameMap *map,
+				 const char *type_suffix)
+{
+	const char *msg;
+	char		old_file[MAXPGPATH];
+	char		new_file[MAXPGPATH];
+	int			fd;
+	int			segno;
+	char		extent_suffix[65];
 	
 	/*
 	 * Now copy/link any related segments as well. Remember, PG breaks
 	 * large files into 1GB segments, the first segment has no extension,
 	 * subsequent segments are named relfilenode.1, relfilenode.2,
-		 * relfilenode.3, ...  'fsm' and 'vm' files use underscores so are not
+	 * relfilenode.3.
 	 * copied.
 	 */
-		snprintf(file_pattern, sizeof(file_pattern), "%u.",
-				 maps[mapnum].old_relfilenode);
-
-		for (fileno = 0; fileno < numFiles; fileno++)
+	for (segno = 0;; segno++)
 	{
-			if (strncmp(namelist[fileno], file_pattern,
-						strlen(file_pattern)) == 0)
-			{
-				snprintf(old_file, sizeof(old_file), "%s/%s", maps[mapnum].old_dir,
-						 namelist[fileno]);
-				snprintf(new_file, sizeof(new_file), "%s/%u%s", maps[mapnum].new_dir,
-						 maps[mapnum].new_relfilenode, strchr(namelist[fileno], '.'));
+		if (segno == 0)
+			extent_suffix[0] = '\0';
+		else
+			snprintf(extent_suffix, sizeof(extent_suffix), ".%d", segno);
 
-				unlink(new_file);
-				transfer_relfile(pageConverter, old_file, new_file,
-								 maps[mapnum].nspname, maps[mapnum].relname);
-			}
-		}
-	}
+		snprintf(old_file, sizeof(old_file), "%s/%u%s%s", map->old_dir,
+				 map->old_relfilenode, type_suffix, extent_suffix);
+		snprintf(new_file, sizeof(new_file), "%s/%u%s%s", map->new_dir,
+				 map->new_relfilenode, type_suffix, extent_suffix);
 	
-	if (numFiles > 0)
+		/* Is it an extent, fsm, or vm file? */
+		if (type_suffix[0] != '\0' || segno != 0)
 		{
-		for (fileno = 0; fileno < numFiles; fileno++)
-			pg_free(namelist[fileno]);
-		pg_free(namelist);
+			/* Did file open fail? */
+			if ((fd = open(old_file, O_RDONLY)) == -1)
+			{
+				/* File does not exist?  That's OK, just return */
+				if (errno == ENOENT)
+					return;
+				else
+					pg_log(PG_FATAL, "non-existant file error while copying relation \"%s.%s\" (\"%s\" to \"%s\")\n",
+						   map->nspname, map->relname, old_file, new_file);
+			}
+			close(fd);
 		}
-}
 
+		unlink(new_file);
 	
-/*
- * transfer_relfile()
- *
- * Copy or link file from old cluster to new one.
- */
-static void
-transfer_relfile(pageCnvCtx *pageConverter, const char *old_file,
-			  const char *new_file, const char *nspname, const char *relname)
-{
-	const char *msg;
+		/* Copying files might take some time, so give feedback. */
+		pg_log(PG_REPORT, OVERWRITE_MESSAGE, old_file);
 	
 		if ((user_opts.transfer_mode == TRANSFER_MODE_LINK) && (pageConverter != NULL))
 			pg_log(PG_FATAL, "This upgrade requires page-by-page conversion, "
@@ -272,7 +226,7 @@ transfer_relfile(pageCnvCtx *pageConverter, const char *old_file,
 	
 			if ((msg = copyAndUpdateFile(pageConverter, old_file, new_file, true)) != NULL)
 				pg_log(PG_FATAL, "error while copying relation \"%s.%s\" (\"%s\" to \"%s\"): %s\n",
-				   nspname, relname, old_file, new_file, msg);
+					   map->nspname, map->relname, old_file, new_file, msg);
 		}
 		else
 		{
@@ -281,7 +235,9 @@ transfer_relfile(pageCnvCtx *pageConverter, const char *old_file,
 			if ((msg = linkAndUpdateFile(pageConverter, old_file, new_file)) != NULL)
 				pg_log(PG_FATAL,
 					   "error while creating link for relation \"%s.%s\" (\"%s\" to \"%s\"): %s\n",
-				   nspname, relname, old_file, new_file, msg);
+					   map->nspname, map->relname, old_file, new_file, msg);
 		}
+   }
+
 	return;
 }