MDEV-35292 - ALTER TABLE re-creating vector key is no-op with non-copying alter algorithms (default)

ALTER TABLE didn't recognize VECTOR index options change and kept table
intact.

VECTOR indexes have their own options_struct, let ALTER TABLE use it.

Author: svoj

mysql-test/main/vector,aria.rdiff

@@ -572,3 +572,10 @@
  drop table t1;
  create table t1(v vector(5) not null, vector index(v));
  alter table t1 add column a int;
+@@ -889,5 +879,5 @@ Table	Create Table
+ t	CREATE TABLE `t` (
+   `v` vector(1) NOT NULL,
+   VECTOR KEY `v` (`v`) `distance`=cosine
+-) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
++) ENGINE=Aria DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci PAGE_CHECKSUM=1
+ drop table t;

mysql-test/main/vector,myisam.rdiff

@@ -509,3 +509,10 @@
 -) ENGINE=InnoDB AUTO_INCREMENT=11 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
 +) ENGINE=MyISAM AUTO_INCREMENT=11 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
  drop table t1;
+@@ -877,5 +877,5 @@
+ t	CREATE TABLE `t` (
+   `v` vector(1) NOT NULL,
+   VECTOR KEY `v` (`v`) `distance`=cosine
+-) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
++) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
+ drop table t;

mysql-test/main/vector.result

@@ -877,3 +877,17 @@ drop table t1;
 create table t1(v vector(5) not null, vector index(v));
 alter table t1 add column a int;
 drop table t1;
+#
+# MDEV-35292 - ALTER TABLE re-creating vector key is no-op with
+#              non-copying alter algorithms (default)
+#
+create table t (v vector(1) not null, vector(v) distance=euclidean);
+insert into t values (0x31313131);
+alter table t drop index v, add vector(v) distance=cosine;
+show create table t;
+Table	Create Table
+t	CREATE TABLE `t` (
+  `v` vector(1) NOT NULL,
+  VECTOR KEY `v` (`v`) `distance`=cosine
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
+drop table t;

mysql-test/main/vector.test

@@ -430,3 +430,13 @@ drop table t1;
 create table t1(v vector(5) not null, vector index(v));
 alter table t1 add column a int;
 drop table t1;
+
+--echo #
+--echo # MDEV-35292 - ALTER TABLE re-creating vector key is no-op with
+--echo #              non-copying alter algorithms (default)
+--echo #
+create table t (v vector(1) not null, vector(v) distance=euclidean);
+insert into t values (0x31313131); # Optional, fails either way
+alter table t drop index v, add vector(v) distance=cosine;
+show create table t;
+drop table t;

mysql-test/main/vector2.result

@@ -143,7 +143,7 @@ Table	Create Table
 t	CREATE TABLE `t` (
   `a` int(11) DEFAULT NULL,
   `v` vector(10) NOT NULL,
-  VECTOR KEY `v` (`v`) `m`=10 `distance`='cosine'
+  VECTOR KEY `v` (`v`) `distance`='cosine'
 ) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_uca1400_ai_ci
 drop table t;
 set mhnsw_default_distance= default;

sql/sql_table.cc

@@ -6794,6 +6794,8 @@ Compare_keys compare_keys_but_name(const KEY *table_key, const KEY *new_key,
     return Compare_keys::NotEqual;
 
   if (engine_options_differ(table_key->option_struct, new_key->option_struct,
+                            table_key->algorithm == HA_KEY_ALG_VECTOR ?
+                            mhnsw_index_options :
                             table->file->ht->index_options))
     return Compare_keys::NotEqual;