# ==== Purpose ====
#
# This test case will test the concurrency between the receiver (a.k.a. I/O)
# thread and the applier (a.k.a. SQL) thread when the receiver is writing
# events to the same relay log file the applier is reading (the "hot" log).
#
# The test uses debug instrumentation to pause the receiver thread while
# holding the locks it uses when writing events to the relay log, and make
# the SQL thread to consume the events on the same relay log file.
#
# ==== Related Bugs and Worklogs ====
#
# WL#8599: Reduce contention in IO and SQL threads
#

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

# Create one table, populate it, then drop it
CREATE TABLE t1 (c1 INT) ENGINE=InnoDB;
--source include/sync_slave_sql_with_master.inc

# Hold the applier thread executing a new event.
LOCK TABLES t1 WRITE;

--source include/rpl_connection_master.inc
INSERT INTO t1 (c1) VALUES (1);

# Wait until the applier reached the waiting point
--source include/rpl_connection_slave.inc
--let $show_statement= SHOW PROCESSLIST
--let $field= State
--let $condition= = 'Waiting for table metadata lock'
--source include/wait_show_condition.inc

--source include/rpl_connection_master.inc
--let $num_inserts= 5
--echo Populate the table with additional $num_inserts rows
--disable_query_log
--let $i= 1
while ($i < $num_inserts)
{
  --inc $i
  --eval INSERT INTO t1 (c1) VALUES ($i)
}
--enable_query_log

--source include/sync_slave_io_with_master.inc

# Add debug instrumentation to hold the receiver thread
# while writing to the relay log.
--let $debug_point=pause_on_queue_event_after_write_buffer
--source include/add_debug_point.inc

# Generate a new transaction to make the receiver to work
--source include/rpl_connection_master.inc
DROP TABLE t1;

# Wait until the receiver reached the debug point
--source include/rpl_connection_slave.inc
SET DEBUG_SYNC='now WAIT_FOR receiver_reached_pause_on_queue_event';

# At this point, we have the receiver thread holding the relay log LOCK_log
# and mi->data_lock. The applier thread is applying the same relay log file
# and should progress normally.

# Let the applier "fly"...
UNLOCK TABLES;

--echo Wait until all the inserts are applied
--let $wait_condition= SELECT COUNT(*) = $num_inserts FROM t1
--source include/wait_condition_or_abort.inc

# It is possible to show the events in the active relay log
--let $binlog_file= slave-relay-bin.000002
--let $binlog_limit= 1, 6
--let $keep_gtid_events= 1
--let $mask_anonymous_gtid_events= 1
--source include/show_relaylog_events.inc

--let $debug_point=pause_on_queue_event_after_write_buffer
--source include/remove_debug_point.inc
SET DEBUG_SYNC='now SIGNAL receiver_continue_queuing_event';

# Cleanup
--source include/rpl_end.inc