# 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;

} {SEARCH 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;

} {SEARCH 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;

} {SEARCH 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;

} {SEARCH t1 USING INDEX t1_c (c=?)}

finish_test