I_S.VECTOR_INDEXES: Cache overflow resets values but does not increase CACHE_OVERFLOWS counter

--source include/have_sequence.inc

--source include/have_innodb.inc

SET @cachesize.save = @@mhnsw_max_cache_size;

SET GLOBAL mhnsw_max_cache_size= 16*1024*1024;

CREATE TABLE t (

  id INT PRIMARY KEY,

  v VECTOR(2000) NOT NULL,

  VECTOR vi(v)

) ENGINE=InnoDB;

INSERT INTO t SELECT seq,

  VEC_FromText(CONCAT('[', seq, ',', REPEAT('1,', 1998), '1]'))

FROM seq_1_to_3000;

SELECT CACHED_NODES, MEMORY_SIZE, CACHE_OVERFLOWS

  FROM INFORMATION_SCHEMA.VECTOR_INDEXES;

--echo #

--echo # With default mhnsw_ef_search=20 this query

--echo # should not overflow the cache

--echo #

SELECT id, VEC_DISTANCE_EUCLIDEAN(

    v, VEC_FromText(CONCAT('[0,', REPEAT('1,', 1998), '1]'))) d FROM t

  ORDER BY d LIMIT 1;

SELECT CACHED_NODES, MEMORY_SIZE, CACHE_OVERFLOWS

  FROM INFORMATION_SCHEMA.VECTOR_INDEXES;

SET mhnsw_ef_search= 10000;

--echo #

--echo # ... but with mhnsw_ef_search=10000 it probably should

--echo #

SELECT id, VEC_DISTANCE_EUCLIDEAN(

    v, VEC_FromText(CONCAT('[0,', REPEAT('1,', 1998), '1]'))) d FROM t

  ORDER BY d LIMIT 1;

SELECT CACHED_NODES, MEMORY_SIZE, CACHE_OVERFLOWS

  FROM INFORMATION_SCHEMA.VECTOR_INDEXES;

DROP TABLE t;

SET GLOBAL mhnsw_max_cache_size= @cachesize.save;

SELECT CACHED_NODES, MEMORY_SIZE, CACHE_OVERFLOWS

FROM INFORMATION_SCHEMA.VECTOR_INDEXES;

CACHED_NODES	MEMORY_SIZE	CACHE_OVERFLOWS

0	0	NULL

#

# With default mhnsw_ef_search=20 this query

# should not overflow the cache

#

SELECT id, VEC_DISTANCE_EUCLIDEAN(

v, VEC_FromText(CONCAT('[0,', REPEAT('1,', 1998), '1]'))) d FROM t

ORDER BY d LIMIT 1;

id	d

1	1

SELECT CACHED_NODES, MEMORY_SIZE, CACHE_OVERFLOWS

FROM INFORMATION_SCHEMA.VECTOR_INDEXES;

CACHED_NODES	MEMORY_SIZE	CACHE_OVERFLOWS

362	4194176	0

SET mhnsw_ef_search= 10000;

#

# ... but with mhnsw_ef_search=10000 it probably should

#

SELECT id, VEC_DISTANCE_EUCLIDEAN(

v, VEC_FromText(CONCAT('[0,', REPEAT('1,', 1998), '1]'))) d FROM t

ORDER BY d LIMIT 1;

id	d

1	1

SELECT CACHED_NODES, MEMORY_SIZE, CACHE_OVERFLOWS

FROM INFORMATION_SCHEMA.VECTOR_INDEXES;

CACHED_NODES	MEMORY_SIZE	CACHE_OVERFLOWS

0	0	NULL