MDEV-19529 InnoDB hang on DROP FULLTEXT INDEX

Problem:
=======
  During dropping of fts index, InnoDB waits for fts_optimize_remove_table()
and it holds dict_sys->mutex and dict_operaiton_lock even though the
table id is not present in the queue. But fts_optimize_thread does wait
for dict_sys->mutex to process the unrelated table id from the slot.

Solution:
========
  Whenever table is added to fts_optimize_wq, update the fts_status
of in-memory fts subsystem to TABLE_IN_QUEUE. Whenever drop index
wants to remove table from the queue, it can check the fts_status
to decide whether it should send the MSG_DELETE_TABLE to the queue.

Removed the following functions because these are all deadcode.
dict_table_wait_for_bg_threads_to_exit(),
fts_wait_for_background_thread_to_start(),fts_start_shutdown(), fts_shudown().

1 files changed, 3 insertions, 4 deletions

diff --git a/storage/innobase/row/row0mysql.cc b/storage/innobase/row/row0mysql.cc
index 52aa43384f7..c6d9909a6fc 100644
--- a/storage/innobase/row/row0mysql.cc
+++ b/storage/innobase/row/row0mysql.cc
@@ -3829,11 +3829,11 @@ next_rec:
 			DBUG_EXECUTE_IF("ib_trunc_sleep_before_fts_cache_clear",
 					os_thread_sleep(10000000););
 
-			table->fts->fts_status |= TABLE_DICT_LOCKED;
+			table->fts->dict_locked = true;
 			fts_update_next_doc_id(trx, table, 0);
 			fts_cache_clear(table->fts->cache);
 			fts_cache_init(table->fts->cache);
-			table->fts->fts_status &= ~TABLE_DICT_LOCKED;
+			table->fts->dict_locked = false;
 		}
 	}
 
@@ -4434,8 +4434,7 @@ do_drop:
 			/* Need to set TABLE_DICT_LOCKED bit, since
 			fts_que_graph_free_check_lock would try to acquire
 			dict mutex lock */
-			table->fts->fts_status |= TABLE_DICT_LOCKED;
-
+			table->fts->dict_locked = true;
 			fts_free(table);
 		}