File: derived_correlated_hypergraph.result

package info (click to toggle)
mysql-8.0 8.0.43-3
  • links: PTS, VCS
  • area: main
  • in suites: sid
  • size: 1,273,924 kB
  • sloc: cpp: 4,684,605; ansic: 412,450; pascal: 108,398; java: 83,641; perl: 30,221; cs: 27,067; sql: 26,594; sh: 24,181; python: 21,816; yacc: 17,169; php: 11,522; xml: 7,388; javascript: 7,076; makefile: 2,194; lex: 1,075; awk: 670; asm: 520; objc: 183; ruby: 97; lisp: 86
file content (33 lines) | stat: -rw-r--r-- 1,074 bytes parent folder | download 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
 
#
# Bug#33616174: Querying data dictionary table KEY_COLUMN_USAGE is
#               slow with hypergraph enabled
#
CREATE TABLE t1(x INT);
CREATE TABLE t2(pk INT PRIMARY KEY);
INSERT INTO t1 VALUES (1);
INSERT INTO t2 VALUES (1), (2), (3), (4), (5), (6), (7), (8), (9), (10);
ANALYZE TABLE t1, t2;
Table	Op	Msg_type	Msg_text
test.t1	analyze	status	OK
test.t2	analyze	status	OK
EXPLAIN FORMAT=TREE
SELECT 1 FROM t1, LATERAL (SELECT DISTINCT t1.x) AS dt, t2
WHERE t2.pk = dt.x;
EXPLAIN
-> Nested loop inner join  (cost=0.5..0.5 rows=1)
    -> Table scan on t1  (cost=0.25..0.25 rows=1)
    -> Nested loop inner join  (cost=0.25..0.25 rows=1)
        -> Stream results  (cost=0..0 rows=1)
            -> Rows fetched before execution  (cost=0..0 rows=1)
        -> Single-row index lookup on t2 using PRIMARY (pk=dt.x)  (cost=0.25..0.25 rows=1)

Warnings:
Note	1276	Field or reference 'test.t1.x' of SELECT #2 was resolved in SELECT #1
SELECT 1 FROM
t1,
LATERAL (SELECT DISTINCT t1.x) AS dt1,
LATERAL (SELECT DISTINCT dt1.x) AS dt2
WHERE dt1.x = dt2.x;
1
1
DROP TABLE t1, t2;