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
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
|
# 2020-02-23
#
# The author disclaims copyright to this source code. In place of
# a legal notice, here is a blessing:
#
# May you do good and not evil.
# May you find forgiveness for yourself and forgive others.
# May you share freely, never taking more than you give.
#
#***********************************************************************
# Tests for functionality related to ANALYZE.
#
set testdir [file dirname $argv0]
source $testdir/tester.tcl
ifcapable !stat4 {
finish_test
return
}
set testprefix analyzeG
#-------------------------------------------------------------------------
# Test cases 1.* seek to verify that even if an index is not used, its
# stat4 data may be used by the planner to estimate the number of
# rows that match an unindexed constraint on the same column.
#
do_execsql_test 1.0 {
PRAGMA automatic_index = 0;
CREATE TABLE t1(a, x);
CREATE TABLE t2(b, y);
WITH s(i) AS (
SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
)
INSERT INTO t1 SELECT (i%50), NULL FROM s;
WITH s(i) AS (
SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
)
INSERT INTO t2 SELECT (CASE WHEN i<95 THEN 44 ELSE i END), NULL FROM s;
}
# Join tables t1 and t2. Both contain 100 rows. (a=44) matches 2 rows
# in "t1", (b=44) matches 95 rows in table "t2". But the planner doesn't
# know this, so it has no preference as to which order the tables are
# scanned in. In practice this means that tables are scanned in the order
# they are specified in in the FROM clause.
do_eqp_test 1.1.1 {
SELECT * FROM t1, t2 WHERE a=44 AND b=44;
} {
}
do_eqp_test 1.1.2 {
SELECT * FROM t2, t1 WHERE a=44 AND b=44
} {
QUERY PLAN
|--SCAN t2
`--SCAN t1
}
do_execsql_test 1.2 {
CREATE INDEX t2b ON t2(b);
ANALYZE;
}
# Now, with the ANALYZE data, the planner knows that (b=44) matches a
# large number of rows. So it elects to scan table "t1" first, regardless
# of the order in which the tables are specified in the FROM clause.
do_eqp_test 1.3.1 {
SELECT * FROM t1, t2 WHERE a=44 AND b=44;
} {
QUERY PLAN
|--SCAN t1
`--SCAN t2
}
do_eqp_test 1.3.2 {
SELECT * FROM t2, t1 WHERE a=44 AND b=44
} {
QUERY PLAN
|--SCAN t1
`--SCAN t2
}
finish_test
|
