Bug #30933728 INNODB FTS PHRASE SEARCH HIT AN ASSERT

Problem:
In Full-text phrase search, we filter out row that do not contain
all the tokens in the phrase.
If we do not filter out doc_id that doesn't appear in all the
token's doc_id lists then we hit an assert.

Fix:
if any of the token has last doc_id equal to ith doc_id of the first
token doc_id list then filter out rest of the higher doc_ids.

RB: 24909
Reviewed by : Annamalai Gurusami <annamalai.gurusami@oracle.com>

This is a cherry-pick of
mysql/mysql-server@5aa075277dfe84a17a0331c57a6fe9b91dafb4cf
but without a test case, because the test case depends on an n-gram
tokenizer that will be missing from MariaDB until MDEV-10267 is added.

1 files changed, 17 insertions, 14 deletions

diff --git a/storage/innobase/fts/fts0que.cc b/storage/innobase/fts/fts0que.cc
index be758c13d52..df2b330fe4b 100644
--- a/storage/innobase/fts/fts0que.cc
+++ b/storage/innobase/fts/fts0que.cc
@@ -4421,24 +4421,27 @@ fts_phrase_or_proximity_search(
 			if (k == ib_vector_size(query->match_array[j])) {
 				end_list = TRUE;
 
-				if (match[j]->doc_id != match[0]->doc_id) {
-					/* no match */
-					if (query->flags & FTS_PHRASE) {
-						ulint	s;
+				if (query->flags & FTS_PHRASE) {
+					ulint	s;
+					/* Since i is the last doc id in the
+					match_array[j], remove all doc ids > i
+					from the match_array[0]. */
+					fts_match_t*    match_temp;
+					for (s = i + 1; s < n_matched; s++) {
+						match_temp = static_cast<
+						fts_match_t*>(ib_vector_get(
+						query->match_array[0], s));
+						match_temp->doc_id = 0;
+					}
 
+					if (match[j]->doc_id !=
+						match[0]->doc_id) {
+						/* no match */
 						match[0]->doc_id = 0;
-
-						for (s = i + 1; s < n_matched;
-						     s++) {
-							match[0] = static_cast<
-							fts_match_t*>(
-							ib_vector_get(
-							query->match_array[0],
-							s));
-							match[0]->doc_id = 0;
-						}
 					}
+				}
 
+				if (match[j]->doc_id != match[0]->doc_id) {
 					goto func_exit;
 				}
 			}