--source include/have_innodb.inc
--source include/have_debug.inc
--source include/master-slave.inc

--connection slave
--source include/stop_slave.inc
# Since we inject an error updating mysql.gtid_slave_pos, we will get different
# output depending on whether it is InnoDB or MyISAM (roll back or no roll
# back). So fix it to make sure we are consistent, in case an earlier test case
# left it as InnoDB.
SET sql_log_bin=0;
ALTER TABLE mysql.gtid_slave_pos ENGINE=Aria;
SET sql_log_bin=1;
--source include/start_slave.inc

--connection master
CREATE TABLE t1 (i int) ENGINE=InnoDB;

--sync_slave_with_master

--echo *** MDEV-4484, incorrect error handling when entries in gtid_slave_pos not found. ***
TRUNCATE TABLE mysql.gtid_slave_pos;

--connection master
INSERT INTO t1 VALUES (1);
--sync_slave_with_master

# Inject an artificial error deleting entries, and check that the error handling code works.
--connection slave
--source include/stop_slave.inc
SET @old_gtid_cleanup_batch_size= @@GLOBAL.gtid_cleanup_batch_size;
SET GLOBAL gtid_cleanup_batch_size= 2;
SET @old_dbug= @@GLOBAL.debug_dbug;
SET GLOBAL debug_dbug="+d,gtid_slave_pos_simulate_failed_delete";
SET sql_log_bin= 0;
CALL mtr.add_suppression("<DEBUG> Error deleting old GTID row");
SET sql_log_bin= 1;
--source include/start_slave.inc

--connection master
--disable_query_log
let $i = 20;
while ($i) {
  eval INSERT INTO t1 VALUES ($i+10);
  dec $i;
}
--enable_query_log
--save_master_pos

--connection slave
--sync_with_master

# Now wait for the slave background thread to try to delete old rows and
# hit the error injection.
--let _TEST_MYSQLD_ERROR_LOG=$MYSQLTEST_VARDIR/log/mysqld.2.err
--perl
  open F, '<', $ENV{'_TEST_MYSQLD_ERROR_LOG'} or die;
  outer: while (1) {
    inner: while (<F>) {
      last outer if /<DEBUG> Error deleting old GTID row/;
    }
    # Easy way to do sub-second sleep without extra modules.
    select(undef, undef, undef, 0.1);
  }
EOF

# Since we injected error in the cleanup code, the rows should remain in
# mysql.gtid_slave_pos. Check that we have at least 20 (more robust against
# non-deterministic cleanup and future changes than checking for exact number).
SELECT COUNT(*), MAX(seq_no) INTO @pre_count, @pre_max_seq_no
  FROM mysql.gtid_slave_pos;
SELECT IF(@pre_count >= 20, "OK", CONCAT("Error: too few rows seen while errors injected: ", @pre_count));
SET GLOBAL debug_dbug= @old_dbug;

--connection master
--disable_query_log
let $i = 20;
while ($i) {
  eval INSERT INTO t1 VALUES ($i+40);
  dec $i;
}
--enable_query_log
--sync_slave_with_master

--connection slave
# Now check that 1) rows are being deleted again after removing error
# injection, and 2) old rows are left that failed their delete while errors
# where injected (again compensating for non-deterministic deletion).
# Deletion is async and slightly non-deterministic, so we wait for at
# least 10 of the 20 new rows to be deleted.
let $wait_condition=
  SELECT COUNT(*) <= 20-10
    FROM mysql.gtid_slave_pos
   WHERE seq_no > @pre_max_seq_no;
--source include/wait_condition.inc
SELECT IF(COUNT(*) >= 1, "OK", CONCAT("Error: too few rows seen after errors no longer injected: ", COUNT(*)))
  FROM mysql.gtid_slave_pos
 WHERE seq_no <= @pre_max_seq_no;

# Clean up
--connection master
DROP TABLE t1;
--connection slave
SET GLOBAL gtid_cleanup_batch_size= @old_gtid_cleanup_batch_size;

--source include/rpl_end.inc