Bug #33067260: WL#14419: SIG11 IN MY_FILL_8BIT|STRINGS/CTYPE-SIMPLE.CC

Implicit grouping can make NULL rows in tables that are not marked
to have NULL rows, which causes any filesort after it to potentially
write corrupted data (we assume we don't have to write NULL row flags,
but also assume we don't have to write any field data). ORDER BY
is removed in this case, but we can still have sorts stemming from
ordering clauses in window functions. The old join optimizer has
special code for this case (const plans) and applies the window
functions in a separate way, but the hypergraph optimizer still has the
sort, and gets the crash.

Fix by always counting the input to window functions as ordered when we
have implicit grouping. We don't need the highest possible efficiency
here, as these plans are generally not allowed by the SQL standard
anyway.

Change-Id: If23f3860bcd3b009388c9a7ed1182237995cf8b1

Author: Steinar H. Gunderson

mysql-test/r/window_functions_bugs.result

@@ -1230,3 +1230,19 @@ FROM t1;
 a	SUM(1) OVER (ORDER BY b)	SUM(1) OVER (ORDER BY b DESC)
 1	1	1
 DROP TABLE t1;
+#
+# Bug #33067260: WL#14419: SIG11 IN MY_FILL_8BIT|STRINGS/CTYPE-SIMPLE.CC
+#
+CREATE TABLE t1 (a INTEGER, b VARCHAR(255));
+INSERT INTO t1 VALUES (1,'x');
+INSERT INTO t1 VALUES (-3,'y');
+CREATE TABLE t2 ( a INTEGER );
+SET sql_mode='';
+SELECT MIN(a) AS field1 FROM t1 WHERE b IN ( SELECT a FROM t2 ) ORDER BY LEAD(a, 5, 7) OVER (ORDER BY b);
+field1
+NULL
+SELECT MIN(a), LEAD(a, 5, 7) OVER (ORDER BY b) AS field1 FROM t1 WHERE b IN ( SELECT a FROM t2 ) ORDER BY b;
+MIN(a)	field1
+NULL	7
+SET sql_mode=DEFAULT;
+DROP TABLE t1, t2;

mysql-test/t/window_functions_bugs.test

@@ -764,3 +764,21 @@ SELECT
 FROM t1;
 
 DROP TABLE t1;
+
+--echo #
+--echo # Bug #33067260: WL#14419: SIG11 IN MY_FILL_8BIT|STRINGS/CTYPE-SIMPLE.CC
+--echo #
+
+CREATE TABLE t1 (a INTEGER, b VARCHAR(255));
+INSERT INTO t1 VALUES (1,'x');
+INSERT INTO t1 VALUES (-3,'y');
+
+CREATE TABLE t2 ( a INTEGER );
+
+SET sql_mode='';
+
+SELECT MIN(a) AS field1 FROM t1 WHERE b IN ( SELECT a FROM t2 ) ORDER BY LEAD(a, 5, 7) OVER (ORDER BY b);
+SELECT MIN(a), LEAD(a, 5, 7) OVER (ORDER BY b) AS field1 FROM t1 WHERE b IN ( SELECT a FROM t2 ) ORDER BY b;
+
+SET sql_mode=DEFAULT;
+DROP TABLE t1, t2;

sql/filesort.cc

@@ -1505,7 +1505,10 @@ uint Sort_param::make_sortkey(Bounds_checked_array<uchar> dst,
     if (addon_fields->using_packed_addons()) {
       for (const Sort_addon_field &addonf : *addon_fields) {
         Field *field = addonf.field;
-        if (field->table->has_null_row()) continue;
+        if (field->table->has_null_row()) {
+          assert(field->table->is_nullable());
+          continue;
+        }
         if (addonf.null_bit && field->is_null()) {
           nulls[addonf.null_offset] |= addonf.null_bit;
         } else {

sql/join_optimizer/join_optimizer.cc

@@ -3554,7 +3554,7 @@ static Prealloced_array<AccessPath *, 4> ApplyWindowFunctions(
     for (size_t window_idx = 0; window_idx < join->m_windows.size();
          ++window_idx) {
       Window *window = join->m_windows[window_idx];
-      if (window->m_ordering_idx == -1 ||
+      if (window->m_ordering_idx == -1 || join->implicit_grouping ||
           orderings.DoesFollowOrder(root_path->ordering_state,
                                     window->m_ordering_idx)) {
         if (trace) {

sql/sql_select.cc

@@ -4188,7 +4188,7 @@ bool JOIN::make_tmp_tables_info() {
 
   /*
     If the plan is constant, we will not do window tmp table processing
-    cf. special code path in do_query_block.
+    cf. special code path for handling const plans.
   */
   m_windowing_steps = m_windows.elements > 0 && !plan_is_const() &&
                       !implicit_grouping && !group_optimized_away;