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Bug #49838: DROP INDEX and ADD UNIQUE INDEX for same index may corrupt

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definition at engine

If a single ALTER TABLE contains both DROP INDEX and ADD INDEX using 
the same index name (a.k.a. index modification) we need to disable 
in-place alter table because we can't ask the storage engine to have 
two copies of the index with the same name even temporarily (if we 
first do the ADD INDEX and then DROP INDEX) and we can't modify 
indexes that are needed by e.g. foreign keys if we first do 
DROP INDEX and then ADD INDEX.
Fixed the problem by disabling in-place ALTER TABLE for these cases.
This commit is contained in:
Georgi Kodinov
2010-03-17 16:18:46 +02:00
parent ea09256c74
commit d32f6b13b5
3 changed files with 91 additions and 1 deletions
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46
sql/sql_table.cc
View File

@ -5566,6 +5566,45 @@ err:
DBUG_RETURN(-1);
}
/**
@brief Check if both DROP and CREATE are present for an index in ALTER TABLE
@details Checks if any index is being modified (present as both DROP INDEX
and ADD INDEX) in the current ALTER TABLE statement. Needed for disabling
online ALTER TABLE.
@param table The table being altered
@param alter_info The ALTER TABLE structure
@return presence of index being altered
@retval FALSE No such index
@retval TRUE Have at least 1 index modified
*/
static bool
is_index_maintenance_unique (TABLE *table, Alter_info *alter_info)
{
List_iterator<Key> key_it(alter_info->key_list);
List_iterator<Alter_drop> drop_it(alter_info->drop_list);
Key *key;
while ((key= key_it++))
{
if (key->name)
{
Alter_drop *drop;
drop_it.rewind();
while ((drop= drop_it++))
{
if (drop->type == Alter_drop::KEY &&
!my_strcasecmp(system_charset_info, key->name, drop->name))
return TRUE;
}
}
}
return FALSE;
}
/*
SYNOPSIS
@ -5654,6 +5693,7 @@ compare_tables(TABLE *table,
*/
Alter_info tmp_alter_info(*alter_info, thd->mem_root);
uint db_options= 0; /* not used */
/* Create the prepared information. */
if (mysql_prepare_create_table(thd, create_info,
&tmp_alter_info,
@ -6851,10 +6891,14 @@ view_err:
*/
new_db_type= create_info->db_type;
if (is_index_maintenance_unique (table, alter_info))
need_copy_table= ALTER_TABLE_DATA_CHANGED;
if (mysql_prepare_alter_table(thd, table, create_info, alter_info))
goto err;
need_copy_table= alter_info->change_level;
if (need_copy_table == ALTER_TABLE_METADATA_ONLY)
need_copy_table= alter_info->change_level;
set_table_default_charset(thd, create_info, db);