Merge 10.3 into 10.4

mysql-test/main/partition_pruning.result

@@ -3487,6 +3487,16 @@ a	b	c	d
 1	a	b	1
 drop table t1;
 #
+# MDEV-14667 Assertion `used_parts > 0' failed in ha_partition::init_record_priority_queue.
+#
+create table t1 (a int);
+insert into t1 values (1),(2);
+create table t2 (b int, c int, key(c,b)) partition by hash(b) partitions 2;
+insert into t2 values (3,4),(5,6);
+select straight_join * from t1, t2 where b != NULL;
+a	b	c
+drop table t1, t2;
+#
 # MDEV-17493: Partition pruning doesn't work for nested outer joins
 #
 create table t0(a int);

mysql-test/main/partition_pruning.test

@@ -1538,6 +1538,19 @@ select * from t1 where (a = 1 AND b < 'd' AND (c = 'b' OR (c = 'c' AND d = 1)) O
                        (a = 1 AND b >= 'a' AND (c = 'c' OR (c = 'd' AND d = 2))));
 drop table t1;
 
+--echo #
+--echo # MDEV-14667 Assertion `used_parts > 0' failed in ha_partition::init_record_priority_queue.
+--echo #
+
+create table t1 (a int);
+insert into t1 values (1),(2);
+
+create table t2 (b int, c int, key(c,b)) partition by hash(b) partitions 2;
+insert into t2 values (3,4),(5,6);
+
+select straight_join * from t1, t2 where b != NULL;
+drop table t1, t2;
+
 --echo #
 --echo # MDEV-17493: Partition pruning doesn't work for nested outer joins
 --echo #

sql/ha_partition.cc

@@ -5267,7 +5267,10 @@ bool ha_partition::init_record_priority_queue()
   {
     size_t alloc_len;
     uint used_parts= bitmap_bits_set(&m_part_info->read_partitions);
-    DBUG_ASSERT(used_parts > 0);
+
+    if (used_parts == 0) /* Do nothing since no records expected. */
+      DBUG_RETURN(false);
+
     /* Allocate record buffer for each used partition. */
     m_priority_queue_rec_len= m_rec_length + PARTITION_BYTES_IN_POS;
     if (!m_using_extended_keys)

storage/innobase/handler/handler0alter.cc

@@ -5671,10 +5671,17 @@ static bool innobase_instant_try(
 			case MYSQL_TYPE_MEDIUM_BLOB:
 			case MYSQL_TYPE_BLOB:
 			case MYSQL_TYPE_LONG_BLOB:
+			variable_length:
 				/* Store the empty string for 'core'
 				variable-length NOT NULL columns. */
 				dfield_set_data(d, field_ref_zero, 0);
 				break;
+			case MYSQL_TYPE_STRING:
+				if (col->mbminlen != col->mbmaxlen
+				    && user_table->not_redundant()) {
+					goto variable_length;
+				}
+				/* fall through */
 			default:
 				/* For fixed-length NOT NULL 'core' columns,
 				get a dummy default value from SQL. Note that
@@ -5691,7 +5698,6 @@ static bool innobase_instant_try(
 					: NULL, true, (*af)->ptr, len,
 					dict_table_is_comp(user_table));
 				ut_ad(new_field->field->pack_length() == len);
-
 			}
 		}