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MDEV-24823 Crash with invalid multi-table update of view in 2nd execution of SP

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Before this patch mergeable derived tables / view used in a multi-table
update / delete were merged before the preparation stage.
When the merge of a derived table / view is performed the on expression
attached to it is fixed and ANDed with the where condition of the select S
containing this derived table / view. It happens after the specification of
the derived table / view has been merged into S. If the ON expression refers
to a non existing field an error is reported and some other mergeable derived
tables / views remain unmerged. It's not a problem if the multi-table
update / delete statement is standalone. Yet if it is used in a stored
procedure the select with incompletely merged derived tables / views may
cause a problem for the second call of the procedure. This does not happen
for select queries using derived tables / views, because in this case their
specifications are merged after the preparation stage at which all ON
expressions are fixed.
This patch makes sure that merging of the derived tables / views used in a
multi-table update / delete statement is performed after the preparation
stage.

Approved by Oleksandr Byelkin <sanja@mariadb.com>
This commit is contained in:
Igor Babaev
2021-04-22 20:02:08 -07:00
parent 6f271302b6
commit e3a25793be
7 changed files with 147 additions and 25 deletions
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3
sql/sql_base.cc
View File

@ -7780,7 +7780,8 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
if (table_list->jtbm_subselect)
{
Item *item= table_list->jtbm_subselect->optimizer;
if (table_list->jtbm_subselect->optimizer->fix_fields(thd, &item))
if (!table_list->jtbm_subselect->optimizer->fixed &&
table_list->jtbm_subselect->optimizer->fix_fields(thd, &item))
{
my_error(ER_TOO_MANY_TABLES,MYF(0), static_cast<int>(MAX_TABLES)); /* psergey-todo: WHY ER_TOO_MANY_TABLES ???*/
DBUG_RETURN(1);