bk commit into 5.0 tree (svoj:1.2529) BUG#28838

[Sergey Vojtovich]

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ChangeSet@stripped, 2007-07-18 15:39:13+05:00, svoj@stripped +1 -0
  BUG#28838 - duplicate external_lock in mysql_alter_table
  
  Removed duplicate call to handler::external_lock() when
  ALTER TABLE that doesn't need to copy a table (quick
  ALTER TABLE) was executed.
  
  Also quick ALTER TABLE doesn't hold LOCK_open anymore when
  it enables/disables indexes.

  sql/sql_table.cc@stripped, 2007-07-18 15:39:11+05:00, svoj@stripped +1 -3
    Do not call handler::external_lock() as table is already locked
    by open_ltable().
    
    Also do not hold LOCK_open mutex for alter_table_manage_keys() as
    this function doesn't require LOCK_open (LOCK_open is required by
    wait_while_table_is_used() only).

diff -Nrup a/sql/sql_table.cc b/sql/sql_table.cc
--- a/sql/sql_table.cc	2007-06-15 20:46:58 +05:00
+++ b/sql/sql_table.cc	2007-07-18 15:39:11 +05:00
@@ -3789,11 +3789,9 @@ view_err:
   {
     VOID(pthread_mutex_lock(&LOCK_open));
     wait_while_table_is_used(thd, table, HA_EXTRA_FORCE_REOPEN);
-    table->file->external_lock(thd, F_WRLCK);
+    VOID(pthread_mutex_unlock(&LOCK_open));
     alter_table_manage_keys(table, table->file->indexes_are_disabled(),
                             alter_info->keys_onoff);
-    table->file->external_lock(thd, F_UNLCK);
-    VOID(pthread_mutex_unlock(&LOCK_open));
     error= ha_commit_stmt(thd);
     if (ha_commit(thd))
       error= 1;