Bug #40021: Renaming view fails, archived .frm for view is

            missing after downgrade

Obsolete arc/ directory and view .frm file backup support
has been removed by the patch for bug 17823. However, that
bugfix caused a problem with "live downgrades" of the
server: if we rename some view 4 times under 5.1.29/5.0.72
and then try to rename it under 5.1.28/5.0.70 on the same
database, the server fails with a error:

  query 'RENAME TABLE ... TO ...' failed: 6: Error on
  delete of '....frm-0001' (Errcode: 2)

Also .frm file of that view may be lost (renamed to .frm~).

The server failed because it tried to rename latest 3
backup .frm files renaming the view: the server used an
integer value of the "revision" field of .frm file to
extract those file names. After the fix for bug 17823 those
files were not created/maintained any more, however the
"revision" field was incremented as usual. So, the server
failed renaming non existent files.

This fix solves the problem by removing the support for
"revision" .frm file field:
1. New server silently ignores existent "revision" fields
   in old .frm files and never write it down;
2. Old server assumes, that missing "revision" field in new
   .frm files means default value of 0.
3. Accordingly to the fix for bug 17823 the new server
   drops arc/ directory on alter/rename view, so after
   "live downgrade" old server begins maintenance of the
   arc/ directory from scratch without conflicts with .frm
   files.

1 files changed, 4 insertions, 89 deletions

diff --git a/sql/parse_file.cc b/sql/parse_file.cc
index 2b947fcac4f..ade0709cf0d 100644
--- a/sql/parse_file.cc
+++ b/sql/parse_file.cc
@@ -88,7 +88,6 @@ write_escaped_string(IO_CACHE *file, LEX_STRING *val_s)
     file	pointer to IO_CACHE structure for writing
     base	pointer to data structure
     parameter	pointer to parameter descriptor
-    old_version	for returning back old version number value
 
   RETURN
     FALSE - OK
@@ -96,8 +95,7 @@ write_escaped_string(IO_CACHE *file, LEX_STRING *val_s)
 */
 
 static my_bool
-write_parameter(IO_CACHE *file, gptr base, File_option *parameter,
-		ulonglong *old_version)
+write_parameter(IO_CACHE *file, gptr base, File_option *parameter)
 {
   char num_buf[20];			// buffer for numeric operations
   // string for numeric operations
@@ -125,15 +123,6 @@ write_parameter(IO_CACHE *file, gptr base, File_option *parameter,
       DBUG_RETURN(TRUE);
     break;
   }
-  case FILE_OPTIONS_REV:
-  {
-    ulonglong *val_i= (ulonglong *)(base + parameter->offset);
-    *old_version= (*val_i)++;
-    num.set(*val_i, &my_charset_bin);
-    if (my_b_append(file, (const byte *)num.ptr(), num.length()))
-      DBUG_RETURN(TRUE);
-    break;
-  }
   case FILE_OPTIONS_TIMESTAMP:
   {
     /* string have to be allocated already */
@@ -205,7 +194,6 @@ write_parameter(IO_CACHE *file, gptr base, File_option *parameter,
     base		base address for parameter reading (structure like
 			TABLE)
     parameters		parameters description
-    max_versions	number of versions to save
 
   RETURN
     FALSE - OK
@@ -215,13 +203,11 @@ write_parameter(IO_CACHE *file, gptr base, File_option *parameter,
 my_bool
 sql_create_definition_file(const LEX_STRING *dir, const LEX_STRING *file_name,
 			   const LEX_STRING *type,
-			   gptr base, File_option *parameters,
-			   uint max_versions)
+			   gptr base, File_option *parameters)
 {
   File handler;
   IO_CACHE file;
   char path[FN_REFLEN+1];	// +1 to put temporary file name for sure
-  ulonglong old_version= ULONGLONG_MAX;
   int path_end;
   File_option *param;
   DBUG_ENTER("sql_create_definition_file");
@@ -255,7 +241,7 @@ sql_create_definition_file(const LEX_STRING *dir, const LEX_STRING *file_name,
     if (my_b_append(&file, (const byte *)param->name.str,
                     param->name.length) ||
 	my_b_append(&file, (const byte *)STRING_WITH_LEN("=")) ||
-	write_parameter(&file, base, param, &old_version) ||
+	write_parameter(&file, base, param) ||
 	my_b_append(&file, (const byte *)STRING_WITH_LEN("\n")))
       goto err_w_cache;
   }
@@ -269,55 +255,6 @@ sql_create_definition_file(const LEX_STRING *dir, const LEX_STRING *file_name,
   }
 
   path[path_end]='\0';
-#ifdef FRM_ARCHIVE
-  // archive copies management: disabled unused feature (see bug #17823).
-  if (!access(path, F_OK))
-  {
-    if (old_version != ULONGLONG_MAX && max_versions != 0)
-    {
-      // save backup
-      char path_arc[FN_REFLEN];
-      // backup old version
-      char path_to[FN_REFLEN];
-
-      // check archive directory existence
-      fn_format(path_arc, "arc", dir->str, "", MY_UNPACK_FILENAME);
-      if (access(path_arc, F_OK))
-      {
-	if (my_mkdir(path_arc, 0777, MYF(MY_WME)))
-	{
-	  DBUG_RETURN(TRUE);
-	}
-      }
-
-      my_snprintf(path_to, FN_REFLEN, "%s/%s-%04lu",
-		  path_arc, file_name->str, (ulong) old_version);
-      if (my_rename(path, path_to, MYF(MY_WME)))
-      {
-	DBUG_RETURN(TRUE);
-      }
-
-      // remove very old version
-      if (old_version > max_versions)
-      {
-	my_snprintf(path_to, FN_REFLEN, "%s/%s-%04lu",
-		    path_arc, file_name->str,
-		    (ulong)(old_version - max_versions));
-	if (!access(path_arc, F_OK) && my_delete(path_to, MYF(MY_WME)))
-	{
-	  DBUG_RETURN(TRUE);
-	}
-      }
-    }
-    else
-    {
-      if (my_delete(path, MYF(MY_WME)))	// no backups
-      {
-	DBUG_RETURN(TRUE);
-      }
-    }
-  }
-#endif//FRM_ARCHIVE
 
   {
     // rename temporary file
@@ -346,8 +283,6 @@ err_w_file:
     schema            name of given schema           
     old_name          original file name
     new_name          new file name
-    revision          revision number
-    num_view_backups  number of backups
 
   RETURN
     0 - OK 
@@ -356,8 +291,7 @@ err_w_file:
 */
 my_bool rename_in_schema_file(THD *thd,
                               const char *schema, const char *old_name, 
-                              const char *new_name, ulonglong revision, 
-                              uint num_view_backups)
+                              const char *new_name)
 {
   char old_path[FN_REFLEN], new_path[FN_REFLEN], arc_path[FN_REFLEN];
 
@@ -376,23 +310,6 @@ my_bool rename_in_schema_file(THD *thd,
   strxnmov(arc_path, FN_REFLEN, mysql_data_home, "/", schema, "/arc", NullS);
   (void) unpack_filename(arc_path, arc_path);
   
-#ifdef FRM_ARCHIVE
-  if (revision > 0 && !access(arc_path, F_OK))
-  {
-    ulonglong limit= ((revision > num_view_backups) ?
-                      revision - num_view_backups : 0);
-    for (; revision > limit ; revision--)
-    {
-      my_snprintf(old_path, FN_REFLEN, "%s/%s%s-%04lu",
-		  arc_path, old_name, reg_ext, (ulong)revision);
-      (void) unpack_filename(old_path, old_path);
-      my_snprintf(new_path, FN_REFLEN, "%s/%s%s-%04lu",
-		  arc_path, new_name, reg_ext, (ulong)revision);
-      (void) unpack_filename(new_path, new_path);
-      my_rename(old_path, new_path, MYF(0));
-    }
-  }
-#else//FRM_ARCHIVE
   { // remove obsolete 'arc' directory and files if any
     MY_DIR *new_dirp;
     if ((new_dirp = my_dir(arc_path, MYF(MY_DONT_SORT))))
@@ -401,7 +318,6 @@ my_bool rename_in_schema_file(THD *thd,
       (void) mysql_rm_arc_files(thd, new_dirp, arc_path);
     }
   }
-#endif//FRM_ARCHIVE
   return 0;
 }
 
@@ -838,7 +754,6 @@ File_parser::parse(gptr base, MEM_ROOT *mem_root,
 	  break;
 	}
 	case FILE_OPTIONS_ULONGLONG:
-	case FILE_OPTIONS_REV:
 	  if (!(eol= strchr(ptr, '\n')))
 	  {
 	    my_error(ER_FPARSER_ERROR_IN_PARAMETER, MYF(0),