bk commit into 5.0 tree (davi:1.2524) BUG#31397

[Davi Arnaut]

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ChangeSet@stripped, 2007-10-08 08:44:14-03:00, davi@stripped +3 -0
  Bug#31397 Inconsistent drop table behavior of handler tables.
  
  The current implementation fails to properly discard handlers of
  dropped tables (that were marked for reopen) because it searches
  on the open handler tables list and using the current alias of the
  table being dropped. The problem is that it must not use the open
  handler tables list to search because the table might have been
  closed (marked for reopen) by a flush tables command and also it
  must not use the current table alias at all since multiple different
  aliases may be associated with a single table. This is specially
  visible when a user has two open handlers (using alias) of a same
  table and a flush tables command is issued before the table is
  dropped (see test case).
  
  The solution is to simple scan the handlers hash table searching
  for, and deleting all handlers with matching table names if the
  reopen flag is not passed to the flush function, indicating that
  the handlers should be deleted. All matching handlers are deleted
  even if the associated the table is not open.

  mysql-test/r/handler.result@stripped, 2007-10-08 08:44:11-03:00, davi@stripped +12 -0
    Add test case result for Bug#3

  mysql-test/t/handler.test@stripped, 2007-10-08 08:44:11-03:00, davi@stripped +19 -0
    Add test case for Bug#3

  sql/sql_handler.cc@stripped, 2007-10-08 08:44:11-03:00, davi@stripped +58 -3
    When dropping tables for a final close, scan the handler's hash table since
    the table might no be in the handlers open table list because the table was
    marked for reopen.

diff -Nrup a/mysql-test/r/handler.result b/mysql-test/r/handler.result
--- a/mysql-test/r/handler.result	2007-08-27 10:37:10 -03:00
+++ b/mysql-test/r/handler.result	2007-10-08 08:44:11 -03:00
@@ -502,3 +502,15 @@ handler t1_alias READ a next where inexi
 ERROR 42S22: Unknown column 'inexistent' in 'field list'
 handler t1_alias close;
 drop table t1;
+drop table if exists t1;
+create table t1 (a int);
+handler t1 open as t1_alias;
+drop table t1;
+create table t1 (a int);
+handler t1 open as t1_alias;
+flush tables;
+drop table t1;
+create table t1 (a int);
+handler t1 open as t1_alias;
+handler t1_alias close;
+drop table t1;
diff -Nrup a/mysql-test/t/handler.test b/mysql-test/t/handler.test
--- a/mysql-test/t/handler.test	2007-08-27 10:37:10 -03:00
+++ b/mysql-test/t/handler.test	2007-10-08 08:44:11 -03:00
@@ -460,3 +460,22 @@ handler t1_alias read a next;
 handler t1_alias READ a next where inexistent > 0;
 handler t1_alias close;
 drop table t1;
+
+#
+# Bug#31397 Inconsistent drop table behavior of handler tables.
+#
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+create table t1 (a int);
+handler t1 open as t1_alias;
+drop table t1;
+create table t1 (a int);
+handler t1 open as t1_alias;
+flush tables;
+drop table t1;
+create table t1 (a int);
+handler t1 open as t1_alias;
+handler t1_alias close;
+drop table t1;
diff -Nrup a/sql/sql_handler.cc b/sql/sql_handler.cc
--- a/sql/sql_handler.cc	2007-08-27 10:37:10 -03:00
+++ b/sql/sql_handler.cc	2007-10-08 08:44:11 -03:00
@@ -124,13 +124,15 @@ static void mysql_ha_hash_free(TABLE_LIS
 
   @param thd Thread identifier.
   @param tables A list of tables with the first entry to close.
+  @param is_locked If LOCK_open is locked.
 
   @note Though this function takes a list of tables, only the first list entry
   will be closed.
   @note Broadcasts refresh if it closed the table.
 */
 
-static void mysql_ha_close_table(THD *thd, TABLE_LIST *tables)
+static void mysql_ha_close_table(THD *thd, TABLE_LIST *tables,
+                                 bool is_locked= false)
 {
   TABLE **table_ptr;
 
@@ -148,13 +150,15 @@ static void mysql_ha_close_table(THD *th
   if (*table_ptr)
   {
     (*table_ptr)->file->ha_index_or_rnd_end();
-    VOID(pthread_mutex_lock(&LOCK_open));
+    if (! is_locked)
+      VOID(pthread_mutex_lock(&LOCK_open));
     if (close_thread_table(thd, table_ptr))
     {
       /* Tell threads waiting for refresh that something has happened */
       broadcast_refresh();
     }
-    VOID(pthread_mutex_unlock(&LOCK_open));
+    if (! is_locked)
+      VOID(pthread_mutex_unlock(&LOCK_open));
   }
 }
 
@@ -602,6 +606,54 @@ err0:
 }
 
 
+/**
+  Drop a list of HANDLER tables and associated hashes
+
+  @param thd        Thread identifier.
+  @param tables     A list of tables with the first entry to close.
+  @param is_locked  If LOCK_open is locked.
+*/
+
+static int mysql_ha_drop(THD *thd, TABLE_LIST *tables, bool is_locked)
+{
+  TABLE_LIST *hash_tables, *head= NULL, *first= tables;
+  DBUG_ENTER("mysql_ha_drop");
+  DBUG_PRINT("enter", ("tables: %p  is_locked: %d", tables, (int) is_locked));
+
+  /* search for all handler with matching table names */
+  for (uint i= 0; i < thd->handler_tables_hash.records; i++)
+  {
+    hash_tables= (TABLE_LIST*) hash_element(&thd->handler_tables_hash, i);
+    for (tables= first; tables; tables= tables->next_local)
+    {
+      if (! *tables->db ||
+          ! my_strcasecmp(&my_charset_latin1, hash_tables->db, tables->db)
&&
+          ! my_strcasecmp(&my_charset_latin1, hash_tables->table_name,
+                          tables->table_name))
+        break;
+    }
+
+    /* specific drop table or drop-all */
+    if (tables || ! first)
+    {
+      hash_tables->next_local= head;
+      head= hash_tables;
+    }
+  }
+
+  while (head)
+  {
+    hash_tables= head;
+    head= hash_tables->next_local;
+    if (hash_tables->table)
+      mysql_ha_close_table(thd, hash_tables, is_locked);
+    hash_delete(&thd->handler_tables_hash, (byte*) hash_tables);
+  }
+
+  DBUG_RETURN(0);
+}
+
+
 /*
   Flush (close) a list of HANDLER tables.
 
@@ -639,6 +691,9 @@ int mysql_ha_flush(THD *thd, TABLE_LIST 
   bool          did_lock= FALSE;
   DBUG_ENTER("mysql_ha_flush");
   DBUG_PRINT("enter", ("tables: %p  mode_flags: 0x%02x", tables, mode_flags));
+
+  if (! (mode_flags & MYSQL_HA_REOPEN_ON_USAGE))
+    DBUG_RETURN(mysql_ha_drop(thd, tables, is_locked));
 
   if (tables)
   {