sqlite/test/analyzeD.test
drh 4fb48e4eb1 Improved debugging output with wheretrace. Fix some typos in test script
comments.

FossilOrigin-Name: 13a37fd487ce7d4f98a12f7a67a9c05dadc66557
2016-03-01 22:41:27 +00:00

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# 2014-10-04
#
# 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.
#
#***********************************************************************
# This file implements regression tests for SQLite library.
# This file implements tests for the ANALYZE command.
#
set testdir [file dirname $argv0]
source $testdir/tester.tcl
set ::testprefix analyzeD
ifcapable {!stat4} {
finish_test
return
}
# Set up a table with the following properties:
#
# * Contains 1000 rows.
# * Column a contains even integers between 0 and 18, inclusive (so that
# a=? for any such integer matches 100 rows).
# * Column b contains integers between 0 and 9, inclusive.
# * Column c contains integers between 0 and 199, inclusive (so that
# for any such integer, c=? matches 5 rows).
# * Then add 7 rows with a new value for "a" - 3001. The stat4 table will
# not contain any samples with a=3001.
#
do_execsql_test 1.0 {
CREATE TABLE t1(a, b, c);
}
do_test 1.1 {
for {set i 1} {$i < 1000} {incr i} {
set c [expr $i % 200]
execsql { INSERT INTO t1(a, b, c) VALUES( 2*($i/100), $i%10, $c ) }
}
execsql {
INSERT INTO t1 VALUES(3001, 3001, 3001);
INSERT INTO t1 VALUES(3001, 3001, 3002);
INSERT INTO t1 VALUES(3001, 3001, 3003);
INSERT INTO t1 VALUES(3001, 3001, 3004);
INSERT INTO t1 VALUES(3001, 3001, 3005);
INSERT INTO t1 VALUES(3001, 3001, 3006);
INSERT INTO t1 VALUES(3001, 3001, 3007);
CREATE INDEX t1_ab ON t1(a, b);
CREATE INDEX t1_c ON t1(c);
ANALYZE;
}
} {}
# With full ANALYZE data, SQLite sees that c=150 (5 rows) is better than
# a=3001 (7 rows).
#
do_eqp_test 1.2 {
SELECT * FROM t1 WHERE a=3001 AND c=150;
} {
0 0 0 {SEARCH TABLE t1 USING INDEX t1_c (c=?)}
}
do_test 1.3 {
execsql { DELETE FROM sqlite_stat1 }
db close
sqlite3 db test.db
} {}
# Without stat1, because 3001 is larger than all samples in the stat4
# table, SQLite thinks that a=3001 matches just 1 row. So it (incorrectly)
# chooses it over the c=150 index (5 rows). Even with stat1 data, things
# worked this way before commit [e6f7f97dbc].
#
do_eqp_test 1.4 {
SELECT * FROM t1 WHERE a=3001 AND c=150;
} {
0 0 0 {SEARCH TABLE t1 USING INDEX t1_ab (a=?)}
}
do_test 1.5 {
execsql {
UPDATE t1 SET a=13 WHERE a = 3001;
ANALYZE;
}
} {}
do_eqp_test 1.6 {
SELECT * FROM t1 WHERE a=13 AND c=150;
} {
0 0 0 {SEARCH TABLE t1 USING INDEX t1_c (c=?)}
}
do_test 1.7 {
execsql { DELETE FROM sqlite_stat1 }
db close
sqlite3 db test.db
} {}
# Same test as 1.4, except this time the 7 rows that match the a=? condition
# do not feature larger values than all rows in the stat4 table. So SQLite
# gets this right, even without stat1 data.
do_eqp_test 1.8 {
SELECT * FROM t1 WHERE a=13 AND c=150;
} {
0 0 0 {SEARCH TABLE t1 USING INDEX t1_c (c=?)}
}
finish_test