MDEV-20867 - Perform careful review of "Server crashes with BACKUP STAGE and FLUSH TABLE table_name"

Reverted original patch (c2e0a0b).

For consistency with "LOCK TABLE <table_name> READ" and "FLUSH TABLES
WITH READ LOCK", which are forbidden under "BACKUP STAGE", forbid "FLUSH
TABLE <table_name> FOR EXPORT" and "FLUSH TABLE <table_name> WITH READ
LOCK" as well.

It'd allow consistent fixes for problems like MDEV-18643.

1 files changed, 3 insertions, 21 deletions

diff --git a/mysql-test/main/backup_interaction.result b/mysql-test/main/backup_interaction.result
index f1354f6778e..3c3071b8e70 100644
--- a/mysql-test/main/backup_interaction.result
+++ b/mysql-test/main/backup_interaction.result
@@ -521,26 +521,8 @@ BACKUP STAGE END;
 CREATE OR REPLACE TABLE t1 (pk INT PRIMARY KEY, f INT);
 BACKUP STAGE START;
 FLUSH TABLE t1 FOR EXPORT;
-UNLOCK TABLES;
-BACKUP STAGE END;
-DROP TABLE t1;
-CREATE TABLE t1 (a INT);
-BACKUP STAGE START;
-FLUSH TABLE t1 FOR EXPORT;
-UNLOCK TABLES;
-connect  con1,localhost,root,,test;
-BACKUP STAGE START;
-connection default;
-BACKUP STAGE END;
-connection con1;
-BACKUP STAGE END;
-disconnect con1;
-connection default;
-DROP TABLE t1;
-CREATE TABLE t1 (a INT);
-BACKUP STAGE START;
-FLUSH TABLES t1 WITH READ LOCK;
-UNLOCK TABLES;
-BACKUP STAGE BLOCK_COMMIT;
+ERROR HY000: Can't execute the command as you have a BACKUP STAGE active
+FLUSH TABLE t1 WITH READ LOCK;
+ERROR HY000: Can't execute the command as you have a BACKUP STAGE active
 BACKUP STAGE END;
 DROP TABLE t1;