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MDEV-41366 Check prefix key match in iterated partition index scan #5821

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MDEV-41366 Check prefix key match in iterated partition index scan #5821

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24 changes: 19 additions & 5 deletions mysql-test/main/partition_index_scan,desc.rdiff
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Original file line number Diff line number Diff line change
Expand Up @@ -287,8 +287,8 @@
show status like 'handler_read_%';
Variable_name Value
Handler_read_first 0
-Handler_read_key 6
+Handler_read_key 7
-Handler_read_key 8
+Handler_read_key 11
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Expand All @@ -301,9 +301,12 @@
) PARTITION BY RANGE COLUMNS(d) (
PARTITION `p1` VALUES LESS THAN (10),
PARTITION `p2` VALUES LESS THAN (20),
@@ -688,8 +688,8 @@
@@ -686,10 +686,10 @@
show status like 'handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 1
-Handler_read_key 1
+Handler_read_key 2
Handler_read_last 0
-Handler_read_next 2
-Handler_read_prev 0
Expand All @@ -312,6 +315,15 @@
Handler_read_retry 0
Handler_read_rnd 0
Handler_read_rnd_deleted 0
@@ -698,7 +698,7 @@
set @js='$out';
select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
-["iterate_over_partitions"]
+["merge_ordered_scans"]
## Case 2: Unordered scans in ha_partition::index_read_map
flush status;
select * from t1 where c = 120 ORDER BY d DESC LIMIT 1;
@@ -725,8 +725,8 @@
Handler_read_first 0
Handler_read_key 1
Expand Down Expand Up @@ -479,7 +491,7 @@
Handler_read_prev 0
Handler_read_retry 0
Handler_read_rnd 0
@@ -1202,18 +1202,18 @@
@@ -1202,20 +1202,20 @@
#
# MDEV-40479: Reverse prefix scan across partitions
#
Expand All @@ -503,3 +515,5 @@
+11
+15
DROP TABLE t1;
#
# MDEV-41366 Wrong result with Case 2 of non-merging partition index scan
235 changes: 230 additions & 5 deletions mysql-test/main/partition_index_scan.result
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Original file line number Diff line number Diff line change
Expand Up @@ -630,8 +630,8 @@ select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
["iterate_over_partitions"]
DROP TABLE t1;
## Case 2: calls to ha_partition::read_range_first and
## ha_partition::index_read_map, via loose index scan
## Case 2 loose index scan: calls to read_range_first iterates;
## index_read_map with AFTER_KEY is merged
CREATE TABLE t1 (
a INT,
b INT,
Expand All @@ -651,7 +651,7 @@ a MIN(b)
show status like 'handler_read_%';
Variable_name Value
Handler_read_first 0
Handler_read_key 6
Handler_read_key 8
Handler_read_last 0
Handler_read_next 0
Handler_read_prev 0
Expand All @@ -662,7 +662,7 @@ Handler_read_rnd_next 0
set @js='$out';
select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
["iterate_over_partitions"]
["both"]
DROP TABLE t1;
CREATE TABLE t1 (
c int,
Expand All @@ -676,7 +676,8 @@ PARTITION `p4` VALUES LESS THAN (40),
PARTITION `p5` VALUES LESS THAN MAXVALUE
);
insert into t1 select t2.seq, t3.seq from seq_100_to_200 t2, seq_1_to_50 t3;
## Case 2: Unordered scans with MRR
## Case 2: iterated partition scans with MRR with ASC key;
## merged scan with index_read_map with DESC key
flush status;
select * from t1 where c=113 and d between 25 and 35 order by d limit 3;
c d
Expand Down Expand Up @@ -1217,3 +1218,227 @@ c
11
6
DROP TABLE t1;
#
# MDEV-41366 Wrong result with Case 2 of non-merging partition index scan
#
# prefix-only PREFIX_LAST_OR_PREV, merged scan
CREATE TABLE t1 (a INT, b INT, c INT, PRIMARY KEY(a,c), KEY(b,c)) ENGINE=InnoDB
PARTITION BY RANGE(c) (PARTITION p0 VALUES LESS THAN (10),
PARTITION p1 VALUES LESS THAN (20));
INSERT INTO t1 VALUES (1,1,5),(2,0,12);
SELECT c FROM t1 FORCE INDEX(b) WHERE b=1 AND c<=15 ORDER BY c DESC;
c
5
set @js='$out';
select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
["merge_ordered_scans"]
DROP TABLE t1;
# same but with desc key
CREATE TABLE t1 (a INT, b INT, c INT, PRIMARY KEY(a,c), KEY(b desc,c desc)) ENGINE=InnoDB
PARTITION BY RANGE(c) (PARTITION p0 VALUES LESS THAN (10),
PARTITION p1 VALUES LESS THAN (20));
INSERT INTO t1 VALUES (1,1,5),(2,0,12);
SELECT c FROM t1 FORCE INDEX(b) WHERE b=0 AND c>=2 ORDER BY c;
c
12
set @js='$out';
select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
["merge_ordered_scans"]
DROP TABLE t1;
# prefix-only KEY_OR_NEXT / PREFIX_LAST_OR_PREV (opt_sum)
# merged scan
CREATE TABLE t1 (a INT, b INT, c INT NOT NULL, PRIMARY KEY(a,c), KEY k(b,c))
ENGINE=InnoDB
PARTITION BY RANGE(c) (PARTITION p0 VALUES LESS THAN (10),
PARTITION p1 VALUES LESS THAN (20),
PARTITION p2 VALUES LESS THAN (30));
# no b=1 in p0 or p2
INSERT INTO t1 VALUES (1,2,5),(2,1,15),(3,0,22);
EXPLAIN
SELECT MIN(c) FROM t1 WHERE b=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
FLUSH STATUS;
SELECT MIN(c) FROM t1 WHERE b=1;
MIN(c)
15
# 3 (merged scan: p0, p1, p2)
SHOW STATUS LIKE 'Handler_read_key';
Variable_name Value
Handler_read_key 3
EXPLAIN
SELECT MAX(c) FROM t1 WHERE b=1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
FLUSH STATUS;
SELECT MAX(c) FROM t1 WHERE b=1;
MAX(c)
15
# 3 (merged scan: p0, p1, p2)
SHOW STATUS LIKE 'Handler_read_key';
Variable_name Value
Handler_read_key 3
DROP TABLE t1;
# index_first with prefix does not qualify Case 2
# neither does index_read_map with AFTER_KEY
CREATE TABLE t1 (a INT, b INT, KEY(a,b)) ENGINE=InnoDB
PARTITION BY RANGE COLUMNS(b) (PARTITION p1 VALUES LESS THAN (100),
PARTITION p2 VALUES LESS THAN (200),
PARTITION p3 VALUES LESS THAN MAXVALUE);
INSERT INTO t1 SELECT seq % 3 + 1, seq FROM seq_1_to_300;
ANALYZE TABLE t1 PERSISTENT FOR ALL;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
EXPLAIN SELECT a, MIN(b) FROM t1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 10 NULL 4 Using index for group-by
SELECT a, MIN(b) FROM t1 GROUP BY a;
a MIN(b)
1 3
2 1
3 2
set @js='$out';
select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
["merge_ordered_scans"]
DROP TABLE t1;
# index_first with prefix does not qualify Case 2
# neither does index_read_map with AFTER_KEY
CREATE TABLE t1 (a INT, c INT, KEY(a,c)) ENGINE=InnoDB
PARTITION BY RANGE COLUMNS(c) (PARTITION p1 VALUES LESS THAN (100),
PARTITION p2 VALUES LESS THAN (200),
PARTITION p3 VALUES LESS THAN MAXVALUE);
INSERT INTO t1 SELECT 1, seq FROM seq_1_to_99;
INSERT INTO t1 SELECT 2, seq FROM seq_100_to_199;
INSERT INTO t1 SELECT 3, seq FROM seq_1_to_99;
ANALYZE TABLE t1 PERSISTENT FOR ALL;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
EXPLAIN SELECT a, MIN(c) FROM t1 GROUP BY a;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range NULL a 10 NULL 4 Using index for group-by
SELECT a, MIN(c) FROM t1 GROUP BY a;
a MIN(c)
1 1
2 100
3 1
set @js='$out';
select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
["merge_ordered_scans"]
DROP TABLE t1;
# AFTER_KEY / BEFORE_KEY merged scan
CREATE TABLE t1 (a INT, b INT, c INT NOT NULL, PRIMARY KEY(a,c), KEY k(b,c))
ENGINE=InnoDB
PARTITION BY RANGE(c) (PARTITION p0 VALUES LESS THAN (10),
PARTITION p1 VALUES LESS THAN (20),
PARTITION p2 VALUES LESS THAN (30));
INSERT INTO t1 VALUES
(1,1,5),(2,2,7),(3,2,10),(4,1,15),(5,2,18),(6,0,22),(7,1,25);
EXPLAIN
SELECT MIN(c) FROM t1 WHERE b=1 AND c>5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
FLUSH STATUS;
SELECT MIN(c) FROM t1 WHERE b=1 AND c>5;
MIN(c)
15
# 3 (merged: p0, p1, p2)
SHOW STATUS LIKE 'Handler_read_key';
Variable_name Value
Handler_read_key 3
EXPLAIN
SELECT MAX(c) FROM t1 WHERE b=1 AND c<25;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
FLUSH STATUS;
SELECT MAX(c) FROM t1 WHERE b=1 AND c<25;
MAX(c)
15
# 3 (merged: p0, p1, p2)
SHOW STATUS LIKE 'Handler_read_key';
Variable_name Value
Handler_read_key 3
DROP TABLE t1;
# KEY_OR_PREV needs a reverse partition scan.
# Ordered scan (HASH)
CREATE TABLE t1 (a INT, KEY k(a)) ENGINE=InnoDB
PARTITION BY HASH(a) PARTITIONS 3;
INSERT INTO t1 SELECT seq FROM seq_1_to_9;
HANDLER t1 OPEN;
HANDLER t1 READ k <= (5);
a
5
HANDLER t1 READ k PREV;
a
4
HANDLER t1 READ k PREV;
a
3
HANDLER t1 READ k <= (0);
a
HANDLER t1 CLOSE;
DROP TABLE t1;
# KEY_OR_PREV merged scan
CREATE TABLE t1 (a INT, b INT, c INT, PRIMARY KEY(a,c), KEY k(b,c))
ENGINE=InnoDB
PARTITION BY RANGE(c) (PARTITION p0 VALUES LESS THAN (10),
PARTITION p1 VALUES LESS THAN (20));
INSERT INTO t1 VALUES (1,1,5),(2,2,7),(3,1,15);
HANDLER t1 OPEN;
HANDLER t1 READ k <= (1,17);
a b c
3 1 15
HANDLER t1 READ k PREV;
a b c
1 1 5
HANDLER t1 CLOSE;
DROP TABLE t1;
# A range spanning several prefix values:
# QUICK_SELECT_DESC reads PREFIX_LAST_OR_PREV (2,15), keypart_map=b,c
CREATE TABLE t1 (a INT, b INT, c INT, PRIMARY KEY(a,c), KEY k(b,c)) ENGINE=InnoDB
PARTITION BY RANGE(c) (PARTITION p0 VALUES LESS THAN (10),
PARTITION p1 VALUES LESS THAN (20));
INSERT INTO t1 VALUES (1,1,7),(2,2,7),(3,1,12),(4,2,12);
EXPLAIN SELECT b, c FROM t1 FORCE INDEX(k)
WHERE b BETWEEN 1 AND 2 AND c BETWEEN 5 AND 15 ORDER BY b DESC, c DESC;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 range k k 9 NULL 4 Using where; Using index
SELECT b, c FROM t1 FORCE INDEX(k)
WHERE b BETWEEN 1 AND 2 AND c BETWEEN 5 AND 15 ORDER BY b DESC, c DESC;
b c
2 12
2 7
1 12
1 7
set @js='$out';
select json_extract(@js,'$**.partitions_index_scan_method');
json_extract(@js,'$**.partitions_index_scan_method')
["merge_ordered_scans"]
DROP TABLE t1;
# reset m_unordered_prefix_len: single partition scan skips
# can_skip_merging_scans()
CREATE TABLE t1 (a INT, b INT, c INT, PRIMARY KEY(a,c),
KEY k(b,c), KEY kc(c,b)) ENGINE=InnoDB
PARTITION BY RANGE(c) (PARTITION p0 VALUES LESS THAN (10),
PARTITION p1 VALUES LESS THAN (20));
INSERT INTO t1 VALUES (1,1,5),(2,1,12),(3,2,13);
HANDLER t1 OPEN;
# 2 partitions, Case 2 on k(b,c): m_unordered_prefix_len = len(b)
HANDLER t1 READ k = (1);
a b c
1 1 5
# full key of kc binds c: single partition p1, reset
HANDLER t1 READ kc = (13,2);
a b c
3 2 13
# expect (2,1,12)
HANDLER t1 READ kc PREV;
a b c
2 1 12
HANDLER t1 CLOSE;
DROP TABLE t1;
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