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MDEV-28965 Assertion failure when preparing UPDATE with derived table in WHERE

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This patch fixes not only the assertion failure in the function
Field_iterator_table_ref::set_field_iterator() but also:
 - fixes the problem of forced materialization of derived tables used
   in subqueries contained in WHERE clauses of single-table and multi-table
   UPDATE and DELETE statements
 - fixes the problem of MDEV-17954 that prevented execution of multi-table
   DELETE statements if they use in their WHERE clauses references to
   the tables that are updated.

The patch must be considered a complement to the patch for MDEV-28883.

Approved by Oleksandr Byelkin <sanja@mariadb.com>
This commit is contained in:
Igor Babaev
2022-07-11 16:57:37 -07:00
parent 3a9358a410
commit 88ca62dc68
27 changed files with 1106 additions and 79 deletions
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63
sql/sql_delete.cc
View File

@ -1117,6 +1117,8 @@ multi_delete::~multi_delete()
table_being_deleted= table_being_deleted->next_local)
{
TABLE *table= table_being_deleted->table;
if (!table)
continue;
table->no_keyread=0;
table->no_cache= 0;
}
@ -1448,6 +1450,34 @@ bool multi_delete::send_eof()
}
/**
@brief Check whether processing to multi-table delete is prohibited
@param thd global context the processed statement
@returns true if processing as multitable is prohibited, false otherwise
@todo
Introduce handler level flag for storage engines that would prohibit
such conversion for any single-table delete.
*/
bool Sql_cmd_delete::processing_as_multitable_delete_prohibited(THD *thd)
{
SELECT_LEX *const select_lex = thd->lex->first_select_lex();
return
((select_lex->order_list.elements &&
select_lex->limit_params.select_limit) ||
thd->lex->has_returning());
}
/**
@brief Perform precheck of table privileges for delete statements
@param thd global context the processed statement
@returns false on success, true on error
*/
bool Sql_cmd_delete::precheck(THD *thd)
{
if (!multitable)
@ -1551,6 +1581,20 @@ bool Sql_cmd_delete::prepare_inner(THD *thd)
DBUG_RETURN(true);
}
if (!multitable)
{
TABLE_LIST *update_source_table= 0;
if (((update_source_table=unique_table(thd, table_list,
table_list->next_global, 0)) ||
table_list->is_multitable()))
{
DBUG_ASSERT(update_source_table || table_list->view != 0);
if (!table_list->is_multitable() &&
!processing_as_multitable_delete_prohibited(thd))
multitable= true;
}
}
if (table_list->has_period())
{
if (table_list->is_view_or_derived())
@ -1635,25 +1679,6 @@ bool Sql_cmd_delete::prepare_inner(THD *thd)
}
}
for (target_tbl= (TABLE_LIST*) aux_tables;
target_tbl;
target_tbl= target_tbl->next_local)
{
/*
Check that table from which we delete is not used somewhere
inside subqueries/view.
*/
{
TABLE_LIST *duplicate;
if ((duplicate= unique_table(thd, target_tbl->correspondent_table,
lex->query_tables, 0)))
{
update_non_unique_table_error(target_tbl->correspondent_table,
"DELETE", duplicate);
DBUG_RETURN(TRUE);
}
}
}
/*
Reset the exclude flag to false so it doesn't interfare
with further calls to unique_table