Merge remote-tracking branch 10.5 into 10.6

Notably MDEV-33290, columnstore disable stays in 10.5.

mysql-test/main/explain.result

@@ -458,3 +458,43 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 NULL	UNION RESULT	<union1,3>	ALL	NULL	NULL	NULL	NULL	NULL	
 Warnings:
 Note	1249	Select 4 was reduced during optimization
+#
+# End of 10.4 tests
+#
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+EXPLAIN SELECT * FROM t1, t2 WHERE t2.b IN (SELECT 5 UNION SELECT 6);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+EXPLAIN DELETE t2 FROM t1, t2 WHERE t2.b IN (SELECT 5 UNION SELECT 6);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+prepare stmt from "EXPLAIN DELETE t2 FROM t1, t2 WHERE t2.b IN (SELECT 5 UNION SELECT 6)";
+execute stmt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+execute stmt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+3	DEPENDENT UNION	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+DROP TABLE t1, t2;
+#
+# End of 10.5 tests
+#

mysql-test/main/explain.test

@@ -372,3 +372,26 @@ drop table t1;
 explain
 VALUES ( (VALUES (2))) UNION VALUES ( (SELECT 3));
 --enable_ps_protocol
+
+--echo #
+--echo # End of 10.4 tests
+--echo #
+
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+CREATE TABLE t2 (b INT);
+INSERT INTO t2 VALUES (3),(4);
+
+EXPLAIN SELECT * FROM t1, t2 WHERE t2.b IN (SELECT 5 UNION SELECT 6);
+EXPLAIN DELETE t2 FROM t1, t2 WHERE t2.b IN (SELECT 5 UNION SELECT 6);
+prepare stmt from "EXPLAIN DELETE t2 FROM t1, t2 WHERE t2.b IN (SELECT 5 UNION SELECT 6)";
+execute stmt;
+execute stmt;
+
+# Cleanup
+
+DROP TABLE t1, t2;
+
+--echo #
+--echo # End of 10.5 tests
+--echo #

sql/log_event_server.cc

@@ -917,6 +917,10 @@ int Log_event_writer::write_header(uchar *pos, size_t len)
 int Log_event_writer::write_data(const uchar *pos, size_t len)
 {
   DBUG_ENTER("Log_event_writer::write_data");
+
+  if (!len)
+    DBUG_RETURN(0);
+
   if (checksum_len)
     crc= my_checksum(crc, pos, len);
 

sql/sql_select.cc

@@ -28716,7 +28716,6 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
 			    bool distinct,const char *message)
 {
   THD *thd=join->thd;
-  select_result *result=join->result;
   DBUG_ENTER("select_describe");
 
   if (join->select_lex->pushdown_select)
@@ -28751,7 +28750,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
 
     if (unit->explainable())
     {
-      if (mysql_explain_union(thd, unit, result))
+      if (mysql_explain_union(thd, unit, unit->result))
         DBUG_VOID_RETURN;
     }
   }

sql/sql_test.cc

@@ -29,14 +29,17 @@
 #include <thr_alarm.h>
 #include "sql_connect.h"
 #include "thread_cache.h"
-#if defined(HAVE_MALLINFO) || defined(HAVE_MALLINFO2)
+
 #if defined(HAVE_MALLOC_H)
 #include <malloc.h>
-#elif defined(HAVE_SYS_MALLOC_H)
-#include <sys/malloc.h>
-#elif defined(HAVE_MALLOC_ZONE)
-#include <malloc/malloc.h>
 #endif
+
+#if defined(HAVE_SYS_MALLOC_H)
+#include <sys/malloc.h>
+#endif
+
+#if defined(HAVE_MALLOC_ZONE)
+#include <malloc/malloc.h>
 #endif
 
 #ifdef HAVE_EVENT_SCHEDULER