@@ -255,9 +255,10 @@ output_completion_banner(char *analyze_script_file_name,
255255deletion_script_file_name );
256256else
257257pg_log (PG_REPORT ,
258- "Could not create a script to delete the old cluster's data\n"
259- "files because user-defined tablespaces exist in the old cluster\n"
260- "directory. The old cluster's contents must be deleted manually.\n" );
258+ "Could not create a script to delete the old cluster's data files\n"
259+ "because user-defined tablespaces or the new cluster's data directory\n"
260+ "exist in the old cluster directory. The old cluster's contents must\n"
261+ "be deleted manually.\n" );
261262}
262263
263264
@@ -693,20 +694,37 @@ create_script_for_old_cluster_deletion(char **deletion_script_file_name)
693694{
694695FILE * script = NULL ;
695696int tblnum ;
696- char old_cluster_pgdata [MAXPGPATH ];
697+ char old_cluster_pgdata [MAXPGPATH ], new_cluster_pgdata [ MAXPGPATH ] ;
697698
698699* deletion_script_file_name = pg_malloc (MAXPGPATH );
699700
700701snprintf (* deletion_script_file_name ,MAXPGPATH ,"delete_old_cluster.%s" ,
701702SCRIPT_EXT );
702703
704+ strlcpy (old_cluster_pgdata ,old_cluster .pgdata ,MAXPGPATH );
705+ canonicalize_path (old_cluster_pgdata );
706+
707+ strlcpy (new_cluster_pgdata ,new_cluster .pgdata ,MAXPGPATH );
708+ canonicalize_path (new_cluster_pgdata );
709+
710+ /* Some people put the new data directory inside the old one. */
711+ if (path_is_prefix_of_path (old_cluster_pgdata ,new_cluster_pgdata ))
712+ {
713+ pg_log (PG_WARNING ,
714+ "\nWARNING: new data directory should not be inside the old data directory, e.g. %s\n" ,old_cluster_pgdata );
715+
716+ /* Unlink file in case it is left over from a previous run. */
717+ unlink (* deletion_script_file_name );
718+ pg_free (* deletion_script_file_name );
719+ * deletion_script_file_name = NULL ;
720+ return ;
721+ }
722+
703723/*
704724 * Some users (oddly) create tablespaces inside the cluster data
705725 * directory. We can't create a proper old cluster delete script in that
706726 * case.
707727 */
708- strlcpy (old_cluster_pgdata ,old_cluster .pgdata ,MAXPGPATH );
709- canonicalize_path (old_cluster_pgdata );
710728for (tblnum = 0 ;tblnum < os_info .num_old_tablespaces ;tblnum ++ )
711729{
712730char old_tablespace_dir [MAXPGPATH ];