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

SET @old_innodb_enable_xap_unlock_unmodified_for_primary_debug=
  @@GLOBAL.innodb_enable_xap_unlock_unmodified_for_primary_debug;
SET GLOBAL innodb_enable_xap_unlock_unmodified_for_primary_debug= 1;

SET @saved_dbug = @@GLOBAL.debug_dbug;

CREATE TABLE t(id INT PRIMARY KEY) ENGINE=InnoDB STATS_PERSISTENT=0;

--let $i = 2

while ($i) {
  --source include/wait_all_purged.inc

  INSERT INTO t VALUES (10), (20), (30);

  --connect(prevent_purge,localhost,root,,)
  start transaction with consistent snapshot;

  --connection default
  DELETE FROM t WHERE id = 20;

  SET @@GLOBAL.debug_dbug=
    "+d,enable_row_purge_remove_clust_if_poss_low_sync_point";

  # Cover both lock_release_on_prepare() and lock_release_on_prepare_try()
  # functions
  if ($i == 1) {
    SET @@GLOBAL.debug_dbug="+d,skip_lock_release_on_prepare_try";
  }

  XA START '1';
  UPDATE t SET id=40 WHERE id=30;
  XA END '1';

  --connection prevent_purge
  COMMIT;

  # stop purge worker after it requested page X-latch, but before
  # lock_update_delete() call
  SET DEBUG_SYNC=
    'now WAIT_FOR row_purge_remove_clust_if_poss_low_before_delete';
  SET @@GLOBAL.debug_dbug=
    "-d,enable_row_purge_remove_clust_if_poss_low_sync_point";

  --connection default
  # lock_rec_unlock_unmodified() is executed either under lock_sys.wr_lock() or
  # under a combination of lock_sys.rd_lock() + record locks hash table cell
  # latch. Stop it before page latch request.
  SET DEBUG_SYNC=
    "lock_rec_unlock_unmodified_start SIGNAL lock_sys_latched WAIT_FOR cont";
  --send XA PREPARE '1'

  --connection prevent_purge
  # let purge thread to continue execution and invoke lock_update_delete(),
  # which, in turns, requests locks_sys related latches.
  SET DEBUG_SYNC= 'now SIGNAL row_purge_remove_clust_if_poss_low_cont';
  SET DEBUG_SYNC= 'now SIGNAL cont';
  --disconnect prevent_purge

  --connection default
  # deadlock if the bug is not fixed, as lock_rec_unlock_unmodified() requests
  # page latch acquired by purge worker, and the purge worker requests lock_sys
  # related latches in lock_update_delete() call, acquired by the current XA
  # in lock_rec_unlock_unmodified() caller.
  --reap
  XA COMMIT '1';

  SET DEBUG_SYNC="RESET";

  TRUNCATE TABLE t;

  --dec $i
}

SET @@GLOBAL.debug_dbug = @saved_dbug;
DROP TABLE t;

SET GLOBAL innodb_enable_xap_unlock_unmodified_for_primary_debug=
  @old_innodb_enable_xap_unlock_unmodified_for_primary_debug;

--source include/wait_until_count_sessions.inc