/
niceSOFT
/
sqlite
Обзор
Документация
Войти
/
niceSOFT
/
sqlite
Код
Задачи
Вики
Пакеты
0
Релизы
0
Аналитика
Безопасность
master
test/tkt3757.test
60 строк
2 KB
drh
Enhance the ANALYZE command so that it gathers statistics in the sqlite_stat1
26 сен 2010, 02:32
26 сен 2010, 02:32
1556405
Код
Авторство
О чём код?
# 2009 March 28 # # 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. # #*********************************************************************** # # Ticket #3757: The cost functions on the query optimizer for the # IN operator can be improved. # # $Id: tkt3757.test,v 1.1 2009/03/29 00:13:04 drh Exp $ set testdir [file dirname $argv0] source $testdir/tester.tcl # Evaluate SQL. Return the result set followed by the # and the number of full-scan steps. # proc count_steps {sql} { set r [db eval $sql] lappend r scan [db status step] sort [db status sort] } # Construct tables # do_test tkt3757-1.1 { db eval { CREATE TABLE t1(x INTEGER, y INTEGER, z TEXT); CREATE INDEX t1i1 ON t1(y,z); INSERT INTO t1 VALUES(1,2,'three'); CREATE TABLE t2(a INTEGER, b TEXT); INSERT INTO t2 VALUES(2, 'two'); ANALYZE; SELECT * FROM sqlite_stat1 ORDER BY 1, 2; } } {t1 t1i1 {1 1 1} t2 {} 1} # Modify statistics in order to make the optimizer then that: # # (1) Table T1 has about 250K entries # (2) There are only about 5 distinct values of T1. # # Then run a query with "t1.y IN (SELECT ..)" in the WHERE clause. # Make sure the index is used. # do_test tkt3757-1.2 { db eval { DELETE FROM sqlite_stat1; INSERT INTO sqlite_stat1 VALUES('t1','t1i1','250000 50000 30'); } count_steps { SELECT * FROM t1 WHERE y IN (SELECT a FROM t2) } } {1 2 three scan 0 sort 0} finish_test