# This test forces InnoDB to behave in a wrong way by missing a lot of calls
# to the log_free_check(). The page flushing is disabled, so the log writer
# thread quickly enters its private so-called extra_margin. This results in
# a warning being emitted (verified by the test). Soon the log_writer runs
# out of space in the extra_margin. Then error is emitted (verified).

# Since then an attempt to update a row ends up in a hanging UPDATE query.

# This is a moment, which simulates the situation that could potentially
# have happened if some code-path was missing calls to the log_free_check()
# and the oldest dirty page became re-modified and latched preventing the
# last_checkpoint_lsn from being advanced (simulated by the disabled page
# cleaners for sake of simplicity). If that happened during ordinary workload,
# the only help can come from DBA, who needs to observe the warning / error
# that were emitted and resize the redo log, increasing its capacity.

# Therefore this is what is done in this test. The redo log becomes increased
# by 1MB. However page cleaners are still disabled so the redo log becomes
# filled again (verified). That happens without exiting the extra_margin
# meanwhile, because the extra_margin is slightly bigger than 1MB.

# Then the page cleaners are enabled and the hanging UPDATE becomes finished
# (verified). Then the original redo log capacity is restored and it might
# take some time but eventually the redo log should become resized down.

# A next UPDATE should be finished easily (verified).

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

# Required to avoid full log buffer flushes and unexpected waits on mutex
# inside binlog code when some threads are waiting for free space in redo.
--source include/not_log_bin.inc

# Save the initial number of concurrent sessions.
--source include/count_sessions.inc

SELECT @@innodb_redo_log_capacity INTO @orig_redo_log_capacity;
SELECT @@innodb_flush_log_at_trx_commit INTO @orig_flush_log_at_trx_commit;

SET GLOBAL innodb_flush_log_at_trx_commit = 0;

--echo # Prepare schema used in the tests.
--source include/ib_log_spammer_init.inc
CREATE TABLE t (a INT PRIMARY KEY, b INT) ENGINE=InnoDB;
INSERT INTO t(a,b) VALUES (1,0);

--echo # Disable page cleaners and prevent page flushing/checkpointing.
--source ../include/log_disable_page_cleaners.inc

--echo # Skip log free checks to fill redo log up to its very end.
SET GLOBAL DEBUG = '+d,log_free_check_skip';

--echo # Request the log writer to generate a signal when it enters the extra_margin.
SET GLOBAL DEBUG = '+d,syncpoint_log_writer_entered_extra_margin';

--echo # Fill redo log until the log writer enters the extra_margin...
--connect(spam_worker_connection,localhost,root,,test)
--send CALL log_spammer()
--connection default

--echo # Redo log data is being generated...

--echo # Wait until the log_writer signaled that it entered the extra margin.
SET DEBUG_SYNC = 'now WAIT_FOR reached_log_writer_entered_extra_margin';

--echo # Log writer entered the extra margin !
let SEARCH_FILE=$MYSQLTEST_VARDIR/log/mysqld.1.err;
let SEARCH_PATTERN=\[Warning\] \[[^]]*\] \[[^]]*\] Redo log is running out of free space, pausing user threads;
--source include/search_pattern.inc

SET GLOBAL innodb_flush_log_at_trx_commit = 2;

--echo # Request the log_writer to generate a signal when it runs out of free space in the extra_margin.
SET GLOBAL DEBUG = '+d,syncpoint_log_writer_ran_out_space';

--echo # Let the log writer continue, and wait until it runs out of free space in the extra_margin.
SET GLOBAL DEBUG = '-d,syncpoint_log_writer_entered_extra_margin';
SET DEBUG_SYNC = 'now SIGNAL continue_log_writer_entered_extra_margin WAIT_FOR reached_log_writer_ran_out_space';

--echo # Log writer ran out of free space !
let SEARCH_FILE=$MYSQLTEST_VARDIR/log/mysqld.1.err;
let SEARCH_PATTERN=\[ERROR\] \[[^]]*\] \[[^]]*\] Out of space in the redo log. Checkpoint LSN:;
--source include/search_pattern.inc

--echo # Let log writer continue to try... It cannot succeed without checkpoint being advanced.
SET GLOBAL DEBUG = '-d,syncpoint_log_writer_ran_out_space';
SET DEBUG_SYNC = 'now SIGNAL continue_log_writer_ran_out_space';

SET GLOBAL innodb_flush_log_at_trx_commit = 1;

--echo # Start a DML query which should be hanging on trx_commit_complete_for_mysql...
--connect(dml_connection,localhost,root,,test)
--send UPDATE t SET b=1 WHERE a=1
--connection default

--echo # Wait until UPDATE becomes visible in information_schema.processlist...
--let $wait_condition=SELECT COUNT(*) = 1 FROM information_schema.processlist WHERE info = 'UPDATE t SET b=1 WHERE a=1'
--let $wait_timeout=60
--source include/wait_condition.inc

--echo # Sleep for 1s to validate it is still there (not yet completed).
--sleep 1

--echo # Ensure the DML has not been completed (no redo space)...
--let $assert_text='The UPDATE is still not finished'
--let $assert_cond= "[SELECT COUNT(*) FROM information_schema.processlist WHERE info = \'UPDATE t SET b=1 WHERE a=1\']" > 0
--source include/assert.inc

--echo # Assume that after resizing up we will be more lucky, not to hit the same issue again
--echo # but at higher redo log size, so let's resume log_free_check() (else: we could quickly
--echo # eat the whole extended space and remain in deadlock)

SET GLOBAL DEBUG = '-d,log_free_check_skip';

--echo # Resize-up redo log a little bit to ensure it will be filled again.
SET GLOBAL innodb_redo_log_capacity = @@innodb_redo_log_capacity + 1048576;

--echo # Ensure the log writer has still NOT exited the extra margin.
let SEARCH_FILE=$MYSQLTEST_VARDIR/log/mysqld.1.err;
let SEARCH_PATTERN=\[Note\] \[[^]]*\] \[[^]]*\] Redo log reclaimed some free space, resuming user threads;
--source include/search_pattern.inc

--echo # Request the log writer to generate a signal when it exits the extra_margin.
SET GLOBAL DEBUG = '+d,syncpoint_log_writer_exited_extra_margin';

--echo ###############################
--echo # Enable page cleaners.
--echo ###############################

--source ../include/log_enable_page_cleaners.inc

--echo # Ensure the started DML becomes completed eventually.
--connection dml_connection
--reap
--connection default
--disconnect dml_connection

--let $assert_text='The UPDATE has been completed'
--let $assert_cond="[SELECT COUNT(*) FROM information_schema.processlist WHERE info = \'UPDATE t SET b=1 WHERE a=1\']" = 0
--source include/assert.inc

--echo # Request the spammer to stop, but do not wait because earlier the log_writer/log_checkpointer
--echo # can be trapped at log_writer_exited_extra_margin

--connect(spam_controller_connection,localhost,root,,test)
--send UPDATE log_spam_controller SET status = 'Stopping' WHERE id = 1
--connection default

--echo # Wait until the log_writer signaled that it exited the extra margin.

SET DEBUG_SYNC = 'now WAIT_FOR reached_log_writer_exited_extra_margin';
SET GLOBAL DEBUG = '-d,syncpoint_log_writer_exited_extra_margin';
SET DEBUG_SYNC = 'now SIGNAL continue_log_writer_exited_extra_margin';

--echo # Ensure the log writer has exited the extra margin.
let SEARCH_FILE=$MYSQLTEST_VARDIR/log/mysqld.1.err;
let SEARCH_PATTERN=\[Note\] \[[^]]*\] \[[^]]*\] Redo log reclaimed some free space, resuming user threads;
--source include/search_pattern.inc

--echo # Wait until the request to stop spammer is completed.

--connection spam_controller_connection
--reap
--connection default
--disconnect spam_controller_connection

--echo # Wait until the spammer is stopped.

--connection spam_worker_connection
--reap
--connection default

--disconnect spam_worker_connection

--let $assert_text='The log spammer is stopped'
--let $assert_cond="[SELECT status FROM log_spam_controller WHERE id = 1]" = "Stopped"
--source include/assert.inc

--echo # Ensure new changes can be done quickly too.
UPDATE t SET b=2 WHERE a=1;
SELECT * FROM t;

--echo # Resize the redo log to its original capacity.

SET GLOBAL innodb_redo_log_capacity = @orig_redo_log_capacity;

--echo # Waiting for status = OK....
let $wait_timeout= 600;
let $wait_condition =
  SELECT variable_value = 'OK'
  FROM performance_schema.global_status
  WHERE variable_name = 'Innodb_redo_log_resize_status';
--source include/wait_condition.inc

--echo # Cleanup
DROP TABLE t;
--source include/ib_log_spammer_cleanup.inc

SET GLOBAL innodb_flush_log_at_trx_commit = @orig_flush_log_at_trx_commit;

SET DEBUG_SYNC = 'RESET';

--source include/wait_until_count_sessions.inc