revision-id: 9ca54bd686f22000116df952841821a7831318f5 (mariadb-10.4.5-43-g9ca54bd686f) parent(s): 2fd82471aba9447e5490b24da5da89c33a21525e author: Varun committer: Varun timestamp: 2019-06-12 13:56:32 +0530 message: MDEV-19705: Assertion `tmp >= 0' failed in best_access_path The reason for hitting the assert is that rec_per_key estimates have some garbage value. So the solution to fix this would be for long unique keys to use use rec_per_key for only 1 keypart, that means rec_per_key[0] would have the estimate. --- mysql-test/main/long_unique.result | 17 ++++++++++++++++- mysql-test/main/long_unique.test | 14 ++++++++++++++ sql/table.cc | 4 +++- 3 files changed, 33 insertions(+), 2 deletions(-) diff --git a/mysql-test/main/long_unique.result b/mysql-test/main/long_unique.result index 3843ff4aff0..03a63d8e7b5 100644 --- a/mysql-test/main/long_unique.result +++ b/mysql-test/main/long_unique.result @@ -1140,7 +1140,7 @@ t1 0 a 1 a A NULL NULL NULL YES HASH t1 0 a 2 c A NULL NULL NULL YES HASH t1 0 b 1 b A NULL NULL NULL YES HASH t1 0 b 2 d A NULL NULL NULL YES HASH -t1 0 e 1 e A 0 NULL NULL YES BTREE +t1 0 e 1 e A NULL NULL NULL YES BTREE drop table t1; #visibility of db_row_hash create table t1 (a blob unique , b blob unique); @@ -1462,4 +1462,19 @@ t1 CREATE TABLE `t1` ( KEY `pk` (`pk`,`a`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 drop table t1; +# +# MDEV-19705: Assertion `tmp >= 0' failed in best_access_path +# +CREATE TABLE t1 (d varchar(10)) ENGINE=MyISAM; +INSERT INTO t1 VALUES ('a'),('q'); +CREATE TABLE t2 (f varchar(10), a2 datetime, b int, a1 varchar(1024), pk int NOT NULL, PRIMARY KEY (pk), UNIQUE KEY (f,a1,a2), KEY f2 (f(4),a2)) ENGINE=MyISAM; +INSERT INTO t2 VALUES ('aaa','1985-09-06',-163,'s',1),('bbb','1995-01-05',3,'pucaz',2),('ccc','0000-00-00',NULL,'help',3),('ddd',NULL,618,'v',4),('eee','1995-12-20',410,'m',5),('ffq','1976-06-12 20:02:56',NULL,'POKNC',6),('dddd','0000-00-00',-328,'hgsu',7); +explain +SELECT t2.b FROM t1 JOIN t2 ON t1.d = t2.f WHERE t2.pk >= 20; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t2 range PRIMARY,f,f2 PRIMARY 4 NULL 1 Using index condition +1 SIMPLE t1 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join) +SELECT t2.b FROM t1 JOIN t2 ON t1.d = t2.f WHERE t2.pk >= 20; +b +drop table t1,t2; set @@GLOBAL.max_allowed_packet= @allowed_packet; diff --git a/mysql-test/main/long_unique.test b/mysql-test/main/long_unique.test index a6bc68f54dc..c0bd77ca5c9 100644 --- a/mysql-test/main/long_unique.test +++ b/mysql-test/main/long_unique.test @@ -542,4 +542,18 @@ alter table t1 modify a varchar(1000); show create table t1; drop table t1; +--echo # +--echo # MDEV-19705: Assertion `tmp >= 0' failed in best_access_path +--echo # + +CREATE TABLE t1 (d varchar(10)) ENGINE=MyISAM; +INSERT INTO t1 VALUES ('a'),('q'); + +CREATE TABLE t2 (f varchar(10), a2 datetime, b int, a1 varchar(1024), pk int NOT NULL, PRIMARY KEY (pk), UNIQUE KEY (f,a1,a2), KEY f2 (f(4),a2)) ENGINE=MyISAM; +INSERT INTO t2 VALUES ('aaa','1985-09-06',-163,'s',1),('bbb','1995-01-05',3,'pucaz',2),('ccc','0000-00-00',NULL,'help',3),('ddd',NULL,618,'v',4),('eee','1995-12-20',410,'m',5),('ffq','1976-06-12 20:02:56',NULL,'POKNC',6),('dddd','0000-00-00',-328,'hgsu',7); +explain +SELECT t2.b FROM t1 JOIN t2 ON t1.d = t2.f WHERE t2.pk >= 20; +SELECT t2.b FROM t1 JOIN t2 ON t1.d = t2.f WHERE t2.pk >= 20; +drop table t1,t2; + set @@GLOBAL.max_allowed_packet= @allowed_packet; diff --git a/sql/table.cc b/sql/table.cc index 699102885c2..d8739b75af5 100644 --- a/sql/table.cc +++ b/sql/table.cc @@ -800,7 +800,8 @@ static bool create_key_infos(const uchar *strpos, const uchar *frm_image_end, { if (strpos + (new_frm_ver >= 1 ? 9 : 7) >= frm_image_end) return 1; - *rec_per_key++=0; + if (!(keyinfo->algorithm == HA_KEY_ALG_LONG_HASH)) + *rec_per_key++=0; key_part->fieldnr= (uint16) (uint2korr(strpos) & FIELD_NR_MASK); key_part->offset= (uint) uint2korr(strpos+2)-1; key_part->key_type= (uint) uint2korr(strpos+5); @@ -828,6 +829,7 @@ static bool create_key_infos(const uchar *strpos, const uchar *frm_image_end, { keyinfo->key_length= HA_HASH_KEY_LENGTH_WITHOUT_NULL; key_part++; // reserved for the hash value + *rec_per_key++=0; } /*