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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
2021-04-19 19:52:06 -07:00
parent 5c5d24c772
commit b3b5d57e78
9 changed files with 171 additions and 26 deletions
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21
sql/sql_lex.cc
View File

@ -4623,6 +4623,27 @@ bool st_select_lex::save_prep_leaf_tables(THD *thd)
}
/**
Set exclude_from_table_unique_test for selects of this select and all selects
belonging to the underlying units of derived tables or views
*/
void st_select_lex::set_unique_exclude()
{
exclude_from_table_unique_test= TRUE;
for (SELECT_LEX_UNIT *unit= first_inner_unit();
unit;
unit= unit->next_unit())
{
if (unit->derived && unit->derived->is_view_or_derived())
{
for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
sl->set_unique_exclude();
}
}
}
/*
Return true if this select_lex has been converted into a semi-join nest
within 'ancestor'.