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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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38
sql/sql_base.cc
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@@ -47,6 +47,8 @@
#include "sql_prepare.h"
#include "sql_statistics.h"
#include "sql_cte.h"
#include "sql_update.h" // class Sql_cmd_update
#include "sql_delete.h" // class Sql_cmd_delete
#include <m_ctype.h>
#include <my_dir.h>
#include <hash.h>
@@ -1194,16 +1196,42 @@ retry:
We come here for queries of type:
INSERT INTO t1 (SELECT tmp.a FROM (select * FROM t1) as tmp);
Try to fix by materializing the derived table
Try to fix by materializing the derived table if one can't do without it.
*/
TABLE_LIST *derived= res->belong_to_derived;
if (derived->is_merged_derived() && !derived->derived->is_excluded())
{
DBUG_PRINT("info",
bool materialize= true;
if (thd->lex->sql_command == SQLCOM_UPDATE)
{
Sql_cmd_update *cmd= (Sql_cmd_update *) (thd->lex->m_sql_cmd);
if (cmd->is_multitable())
materialize= false;
else if (!cmd->processing_as_multitable_update_prohibited(thd))
{
cmd->set_as_multitable();
materialize= false;
}
}
else if (thd->lex->sql_command == SQLCOM_DELETE)
{
Sql_cmd_delete *cmd= (Sql_cmd_delete *) (thd->lex->m_sql_cmd);
if (cmd->is_multitable())
materialize= false;
if (!cmd->processing_as_multitable_delete_prohibited(thd))
{
cmd->set_as_multitable();
materialize= false;
}
}
if (materialize)
{
DBUG_PRINT("info",
("convert merged to materialization to resolve the conflict"));
derived->change_refs_to_fields();
derived->set_materialized_derived();
goto retry;
derived->change_refs_to_fields();
derived->set_materialized_derived();
goto retry;
}
}
}
DBUG_RETURN(res);