BUG#19314480 SEGV IN FTS_OPTIMIZE_THREAD, DICT_TABLE_OPEN_ON_NAME()

OR FTS_IS_SYNC_NEEDED()

Check slot state in fts_is_sync_needed and save table id to open
dict_table_t.

rb#6986 approved by Jimmy.Yang.

Author: Shaohua Wang

storage/innobase/fts/fts0opt.cc

@@ -190,6 +190,8 @@ cycle for a table. */
 struct fts_slot_t {
 	dict_table_t*	table;		/*!< Table to optimize */
 
+	table_id_t	table_id;	/*!< Table id */
+
 	fts_state_t	state;		/*!< State of this slot */
 
 	ulint		added;		/*!< Number of doc ids added since the
@@ -2575,6 +2577,8 @@ fts_optimize_add_table(
 		return;
 	}
 
+	ut_ad(table->cached && table->fts != NULL);
+
 	/* Make sure table with FTS index cannot be evicted */
 	if (table->can_be_evicted) {
 		dict_table_move_from_lru_to_non_lru(table);
@@ -2741,6 +2745,7 @@ fts_optimize_new_table(
 	memset(slot, 0x0, sizeof(*slot));
 
 	slot->table = table;
+	slot->table_id = table->id;
 	slot->state = FTS_STATE_LOADED;
 	slot->interval_time = FTS_OPTIMIZE_INTERVAL_IN_SECS;
 
@@ -2865,7 +2870,8 @@ fts_is_sync_needed(
 		slot = static_cast<const fts_slot_t*>(
 			ib_vector_get_const(tables, i));
 
-		if (slot->table && slot->table->fts) {
+		if (slot->state != FTS_STATE_EMPTY && slot->table
+		    && slot->table->fts) {
 			total_memory += slot->table->fts->cache->total_size;
 		}
 
@@ -3077,9 +3083,11 @@ fts_optimize_thread(
 			if (slot->state != FTS_STATE_EMPTY) {
 				dict_table_t*	table = NULL;
 
-			        table = dict_table_open_on_name(
-					slot->table->name, FALSE, FALSE,
-					DICT_ERR_IGNORE_INDEX_ROOT);
+				/*slot->table may be freed, so we try to open
+				table by slot->table_id.*/
+				table = dict_table_open_on_id(
+					slot->table_id, FALSE,
+					DICT_TABLE_OP_NORMAL);
 
 				if (table) {