xref: /sqlite-3.40.0/test/analyzeD.test (revision 4fb48e4e) 
1# 2014-10-04
2#
3# The author disclaims copyright to this source code.  In place of
4# a legal notice, here is a blessing:
5#
6#    May you do good and not evil.
7#    May you find forgiveness for yourself and forgive others.
8#    May you share freely, never taking more than you give.
9#
10#***********************************************************************
11# This file implements regression tests for SQLite library.
12# This file implements tests for the ANALYZE command.
13#
14
15set testdir [file dirname $argv0]
16source $testdir/tester.tcl
17set ::testprefix analyzeD
18
19ifcapable {!stat4} {
20  finish_test
21  return
22}
23
24
25# Set up a table with the following properties:
26#
27#    * Contains 1000 rows.
28#    * Column a contains even integers between 0 and 18, inclusive (so that
29#      a=? for any such integer matches 100 rows).
30#    * Column b contains integers between 0 and 9, inclusive.
31#    * Column c contains integers between 0 and 199, inclusive (so that
32#      for any such integer, c=? matches 5 rows).
33#    * Then add 7 rows with a new value for "a" - 3001. The stat4 table will
34#      not contain any samples with a=3001.
35#
36do_execsql_test 1.0 {
37  CREATE TABLE t1(a, b, c);
38}
39do_test 1.1 {
40  for {set i 1} {$i < 1000} {incr i} {
41    set c [expr $i % 200]
42    execsql { INSERT INTO t1(a, b, c) VALUES( 2*($i/100), $i%10, $c ) }
43  }
44
45  execsql {
46    INSERT INTO t1 VALUES(3001, 3001, 3001);
47    INSERT INTO t1 VALUES(3001, 3001, 3002);
48    INSERT INTO t1 VALUES(3001, 3001, 3003);
49    INSERT INTO t1 VALUES(3001, 3001, 3004);
50    INSERT INTO t1 VALUES(3001, 3001, 3005);
51    INSERT INTO t1 VALUES(3001, 3001, 3006);
52    INSERT INTO t1 VALUES(3001, 3001, 3007);
53
54    CREATE INDEX t1_ab ON t1(a, b);
55    CREATE INDEX t1_c ON t1(c);
56
57    ANALYZE;
58  }
59} {}
60
61# With full ANALYZE data, SQLite sees that c=150 (5 rows) is better than
62# a=3001 (7 rows).
63#
64do_eqp_test 1.2 {
65  SELECT * FROM t1 WHERE a=3001 AND c=150;
66} {
67  0 0 0 {SEARCH TABLE t1 USING INDEX t1_c (c=?)}
68}
69
70do_test 1.3 {
71  execsql { DELETE FROM sqlite_stat1 }
72  db close
73  sqlite3 db test.db
74} {}
75
76# Without stat1, because 3001 is larger than all samples in the stat4
77# table, SQLite thinks that a=3001 matches just 1 row. So it (incorrectly)
78# chooses it over the c=150 index (5 rows). Even with stat1 data, things
79# worked this way before commit [e6f7f97dbc].
80#
81do_eqp_test 1.4 {
82  SELECT * FROM t1 WHERE a=3001 AND c=150;
83} {
84  0 0 0 {SEARCH TABLE t1 USING INDEX t1_ab (a=?)}
85}
86
87do_test 1.5 {
88  execsql {
89    UPDATE t1 SET a=13 WHERE a = 3001;
90    ANALYZE;
91  }
92} {}
93
94do_eqp_test 1.6 {
95  SELECT * FROM t1 WHERE a=13 AND c=150;
96} {
97  0 0 0 {SEARCH TABLE t1 USING INDEX t1_c (c=?)}
98}
99
100do_test 1.7 {
101  execsql { DELETE FROM sqlite_stat1 }
102  db close
103  sqlite3 db test.db
104} {}
105
106# Same test as 1.4, except this time the 7 rows that match the a=? condition
107# do not feature larger values than all rows in the stat4 table. So SQLite
108# gets this right, even without stat1 data.
109do_eqp_test 1.8 {
110  SELECT * FROM t1 WHERE a=13 AND c=150;
111} {
112  0 0 0 {SEARCH TABLE t1 USING INDEX t1_c (c=?)}
113}
114
115finish_test
116