1 files changed, 98 insertions, 10 deletions

diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index ef05a472ab7..04cf6a479ec 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -238,10 +238,17 @@ uint explain_filename(THD* thd,
       {
         part_name_len= tmp_p - part_name - 1;
         subpart_name= tmp_p + 3;
+	tmp_p+= 3;
+      }
+      else if ((tmp_p[1] == 'Q' || tmp_p[1] == 'q') &&
+               (tmp_p[2] == 'L' || tmp_p[2] == 'l') &&
+                tmp_p[3] == '-')
+      {
+        name_type= TEMP;
+        tmp_p+= 4; /* sql- prefix found */
       }
       else
         res= 2;
-      tmp_p+= 3;
       break;
     case 'T':
     case 't':
@@ -1937,6 +1944,49 @@ bool mysql_rm_table(THD *thd,TABLE_LIST *tables, my_bool if_exists,
 
 
 /**
+  Find the comment in the query.
+  That's auxiliary function to be used handling DROP TABLE [comment].
+
+  @param  thd             Thread handler
+  @param  comment_pos     How many characters to skip before the comment.
+                          Can be either 9 for DROP TABLE or
+                          17 for DROP TABLE IF EXISTS
+  @param  comment_start   returns the beginning of the comment if found.
+
+  @retval  0  no comment found
+  @retval  >0 the lenght of the comment found
+
+*/
+static uint32 comment_length(THD *thd, uint32 comment_pos,
+                             const char **comment_start)
+{
+  const char *query= thd->query();
+  const char *query_end= query + thd->query_length();
+  const uchar *const state_map= thd->charset()->state_map;
+
+  for (; query < query_end; query++)
+  {
+    if (state_map[*query] == MY_LEX_SKIP)
+      continue;
+    if (comment_pos-- == 0)
+      break;
+  }
+  if (query > query_end - 3 /* comment can't be shorter than 4 */ ||
+      state_map[*query] != MY_LEX_LONG_COMMENT || query[1] != '*')
+    return 0;
+  
+  *comment_start= query;
+  
+  for (query+= 3; query < query_end; query++)
+  {
+    if (query[-1] == '*' && query[0] == '/')
+      return query - *comment_start + 1;
+  }
+  return 0;
+}
+
+
+/**
   Execute the drop of a normal or temporary table.
 
   @param  thd             Thread handler
@@ -2011,11 +2061,20 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
   {
     if (!drop_temporary)
     {
+      const char *comment_start;
+      uint32 comment_len;
+
       built_query.set_charset(system_charset_info);
       if (if_exists)
         built_query.append("DROP TABLE IF EXISTS ");
       else
         built_query.append("DROP TABLE ");
+
+      if ((comment_len= comment_length(thd, if_exists ? 17:9, &comment_start)))
+      {
+        built_query.append(comment_start, comment_len);
+        built_query.append(" ");
+      }
     }
 
     if (thd->is_current_stmt_binlog_format_row() || if_exists)
@@ -6935,21 +6994,47 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
     (void) quick_rm_table(new_db_type, new_db, tmp_name, FN_IS_TMP);
   }
   else if (mysql_rename_table(new_db_type, new_db, tmp_name, new_db,
-                              new_alias, FN_FROM_IS_TMP) ||
-           ((new_name != table_name || new_db != db) && // we also do rename
-           (need_copy_table != ALTER_TABLE_METADATA_ONLY ||
-            mysql_rename_table(save_old_db_type, db, table_name, new_db,
-                               new_alias, NO_FRM_RENAME)) &&
-           Table_triggers_list::change_table_name(thd, db, alias, table_name,
-                                                  new_db, new_alias)))
+                              new_alias, FN_FROM_IS_TMP))
   {
     /* Try to get everything back. */
-    error=1;
-    (void) quick_rm_table(new_db_type,new_db,new_alias, 0);
+    error= 1;
     (void) quick_rm_table(new_db_type, new_db, tmp_name, FN_IS_TMP);
     (void) mysql_rename_table(old_db_type, db, old_name, db, alias,
                             FN_FROM_IS_TMP);
   }
+  else if (new_name != table_name || new_db != db)
+  {
+    if (need_copy_table == ALTER_TABLE_METADATA_ONLY &&
+        mysql_rename_table(save_old_db_type, db, table_name, new_db,
+                           new_alias, NO_FRM_RENAME))
+    {
+      /* Try to get everything back. */
+      error= 1;
+      (void) quick_rm_table(new_db_type, new_db, new_alias, 0);
+      (void) mysql_rename_table(old_db_type, db, old_name, db, alias,
+                                FN_FROM_IS_TMP);
+    }
+    else if (Table_triggers_list::change_table_name(thd, db, alias, 
+                                                    table_name, new_db, 
+                                                    new_alias))
+    {
+      /* Try to get everything back. */
+      error= 1;
+      (void) quick_rm_table(new_db_type, new_db, new_alias, 0);
+      (void) mysql_rename_table(old_db_type, db, old_name, db,
+                                alias, FN_FROM_IS_TMP);
+      /*
+        If we were performing "fast"/in-place ALTER TABLE we also need
+        to restore old name of table in storage engine as a separate
+        step, as the above rename affects .FRM only.
+      */
+      if (need_copy_table == ALTER_TABLE_METADATA_ONLY)
+      {
+        (void) mysql_rename_table(save_old_db_type, new_db, new_alias,
+                                  db, table_name, NO_FRM_RENAME); 
+      }
+    }
+  }
 
   if (! error)
     (void) quick_rm_table(old_db_type, db, old_name, FN_IS_TMP);
@@ -7369,7 +7454,10 @@ err:
   thd_progress_next_stage(thd);
 
   if (error > 0)
+  {
+    /* We are going to drop the temporary table */
     to->file->extra(HA_EXTRA_PREPARE_FOR_DROP);
+  }
   if (errpos >= 3 && to->file->ha_end_bulk_insert() && error <= 0)
   {
     to->file->print_error(my_errno,MYF(0));