IB: read lock on partitioned table read [closes #200]

Closes #204

mysql-test/suite/versioning/r/partition.result

@@ -230,6 +230,20 @@ partition by system_time limit 1 (
 partition p0 versioning,
 partition p1 versioning,
 partition pn as of now);
+show create table t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `x` int(11) DEFAULT NULL,
+  `sys_trx_start` ${SYS_TRX_TYPE} GENERATED ALWAYS AS ROW START,
+  `sys_trx_end` ${SYS_TRX_TYPE} GENERATED ALWAYS AS ROW END,
+  PERIOD FOR SYSTEM_TIME (`sys_trx_start`, `sys_trx_end`)
+) ENGINE=${INNODB_OR_MYISAM} DEFAULT CHARSET=latin1 WITH SYSTEM VERSIONING
+ PARTITION BY SYSTEM_TIME LIMIT 1
+(PARTITION p0 VERSIONING ENGINE = ${INNODB_OR_MYISAM},
+ PARTITION p1 VERSIONING ENGINE = ${INNODB_OR_MYISAM},
+ PARTITION pn AS OF NOW ENGINE = ${INNODB_OR_MYISAM})
+alter table t1 drop partition non_existent;
+ERROR HY000: Error in list of partitions to DROP
 insert into t1 values (1), (2);
 select * from t1 partition (pn);
 x

mysql-test/suite/versioning/t/partition.test

@@ -145,6 +145,12 @@ partition by system_time limit 1 (
     partition p1 versioning,
     partition pn as of now);
 
+--replace_result InnoDB ${INNODB_OR_MYISAM} MyISAM ${INNODB_OR_MYISAM} "bigint(20) unsigned" ${SYS_TRX_TYPE} timestamp(6) ${SYS_TRX_TYPE}
+show create table t1;
+
+--error ER_DROP_PARTITION_NON_EXISTENT
+alter table t1 drop partition non_existent;
+
 insert into t1 values (1), (2);
 select * from t1 partition (pn);
 delete from t1;

storage/innobase/handler/ha_innopart.cc

@@ -3059,7 +3059,14 @@ ha_innopart::part_recs_slow(void *_part_elem)
 	{
 		DBUG_ASSERT(bitmap_is_set(&(m_part_info->read_partitions), part_id));
 		set_partition(part_id);
+		bool read_lock_needed = get_lock_type() == F_UNLCK;
+		if (read_lock_needed)
+			ha_external_lock(ha_thd(), F_RDLCK);
 		ha_rows n = ha_innobase::records_new();
+		if (read_lock_needed) {
+			ha_external_lock(ha_thd(), F_UNLCK);
+			ha_commit_one_phase(ha_thd(), false);
+		}
 		update_partition(part_id);
 		if (n == HA_POS_ERROR) {
 			return HA_POS_ERROR;