MDEV-7895 - HANDLER READ doesn't upgrade metadata lock from S to SRbb-mdev7895

Change code for HANDLER READ statements to upgrade S metadata lock to
SR metadata lock for the duration of read. This allows us properly
isolate HANDLER READ from LOCK TABLES WRITE and makes metadata locking
for these statements consistent with locking for other DML.

HANDLER-related tests had to be adjusted to take into account that
HANDLER READ will wait for and acquire SR lock.

1 files changed, 2 insertions, 8 deletions

diff --git a/mysql-test/suite/handler/interface.result b/mysql-test/suite/handler/interface.result
index 89dec29f412..ec613d9f57a 100644
--- a/mysql-test/suite/handler/interface.result
+++ b/mysql-test/suite/handler/interface.result
@@ -273,19 +273,13 @@ ERROR HY000: Storage engine CSV of the table `test`.`t1` doesn't have this optio
 handler t1 close;
 unlock tables;
 drop table t1;
-# Now test case which was reported originally but which no longer
-# triggers execution path which has caused the problem.
+# Now test case which was reported originally.
 create table t1 (a int not null);
 insert into t1 values (1);
 handler t1 open;
 alter table t1 engine=csv;
-# Since S metadata lock was already acquired at HANDLER OPEN time
-# and TL_READ lock requested by HANDLER READ is compatible with
-# ALTER's TL_WRITE_ALLOW_READ the below statement should succeed
-# without waiting. The old version of table should be used in it.
 handler t1 read next;
-a
-1
+ERROR HY000: Storage engine CSV of the table `test`.`t1` doesn't have this option
 handler t1 close;
 drop table t1;
 USE information_schema;