xref: /sqlite-3.40.0/test/limit2.test (revision dfe4e6bb)
1# 2016-05-20
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.  The
12# focus of this file is testing the LIMIT in combination with ORDER BY
13# and in particular, the optimizations in the inner loop that cause an
14# early exit of the inner loop when the LIMIT is reached and the inner
15# loop is emitting rows in ORDER BY order.
16
17
18set testdir [file dirname $argv0]
19source $testdir/tester.tcl
20
21do_execsql_test limit2-100 {
22  CREATE TABLE t1(a,b);
23  WITH RECURSIVE c(x) AS (VALUES(1) UNION ALL SELECT x+1 FROM c WHERE x<1000)
24    INSERT INTO t1(a,b) SELECT 1, (x*17)%1000 + 1000 FROM c;
25  INSERT INTO t1(a,b) VALUES(2,2),(3,1006),(4,4),(5,9999);
26  CREATE INDEX t1ab ON t1(a,b);
27}
28set sqlite_search_count 0
29do_execsql_test limit2-100.1 {
30  SELECT a, b, '|' FROM t1 WHERE a IN (2,4,5,3,1) ORDER BY b LIMIT 5;
31} {2 2 | 4 4 | 1 1000 | 1 1001 | 1 1002 |}
32set fast_count $sqlite_search_count
33set sqlite_search_count 0
34do_execsql_test limit2-100.2 {
35  SELECT a, b, '|' FROM t1 WHERE a IN (2,4,5,3,1) ORDER BY +b LIMIT 5;
36} {2 2 | 4 4 | 1 1000 | 1 1001 | 1 1002 |}
37do_test limit2-100.3 {
38  set slow_count $sqlite_search_count
39  expr {$fast_count < 0.02*$slow_count}
40} {1}
41
42do_execsql_test limit2-110 {
43  CREATE TABLE t2(x,y);
44  INSERT INTO t2(x,y) VALUES('a',1),('a',2),('a',3),('a',4);
45  INSERT INTO t2(x,y) VALUES('b',1),('c',2),('d',3),('e',4);
46  CREATE INDEX t2xy ON t2(x,y);
47}
48set sqlite_search_count 0
49do_execsql_test limit2-110.1 {
50  SELECT a, b, '|' FROM t2, t1 WHERE t2.x='a' AND t1.a=t2.y ORDER BY t1.b LIMIT 5;
51} {2 2 | 4 4 | 1 1000 | 1 1001 | 1 1002 |}
52set fast_count $sqlite_search_count
53set sqlite_search_count 0
54do_execsql_test limit2-110.2 {
55  SELECT a, b, '|' FROM t2, t1 WHERE t2.x='a' AND t1.a=t2.y ORDER BY +t1.b LIMIT 5;
56} {2 2 | 4 4 | 1 1000 | 1 1001 | 1 1002 |}
57set slow_count $sqlite_search_count
58do_test limit2-110.3 {
59  expr {$fast_count < 0.02*$slow_count}
60} {1}
61
62do_execsql_test limit2-120 {
63  DROP INDEX t1ab;
64  CREATE INDEX t1ab ON t1(a,b DESC);
65}
66set sqlite_search_count 0
67do_execsql_test limit2-120.1 {
68  SELECT a, b, '|' FROM t1 WHERE a IN (2,4,5,3,1) ORDER BY b DESC LIMIT 5;
69} {5 9999 | 1 1999 | 1 1998 | 1 1997 | 1 1996 |}
70set fast_count $sqlite_search_count
71set sqlite_search_count 0
72do_execsql_test limit2-120.2 {
73  SELECT a, b, '|' FROM t1 WHERE a IN (2,4,5,3,1) ORDER BY +b DESC LIMIT 5;
74} {5 9999 | 1 1999 | 1 1998 | 1 1997 | 1 1996 |}
75do_test limit2-120.3 {
76  set slow_count $sqlite_search_count
77  expr {$fast_count < 0.02*$slow_count}
78} {1}
79
80# Bug report against the new ORDER BY LIMIT optimization just prior to
81# release.  (Unreleased so there is no ticket).
82#
83# Make sure the optimization is not applied if the inner loop can only
84# provide a single row of output.
85#
86do_execsql_test limit2-200 {
87  CREATE TABLE t200(a, b);
88  WITH RECURSIVE c(x) AS (VALUES(1) UNION ALL SELECT x+1 FROM c WHERE x<1000)
89    INSERT INTO t200(a,b) SELECT x, x FROM c;
90  CREATE TABLE t201(x INTEGER PRIMARY KEY, y);
91  INSERT INTO t201(x,y) VALUES(2,12345);
92
93  SELECT *, '|' FROM t200, t201 WHERE x=b ORDER BY y LIMIT 3;
94} {2 2 2 12345 |}
95do_execsql_test limit2-210 {
96  SELECT *, '|' FROM t200 LEFT JOIN t201 ON x=b ORDER BY y LIMIT 3;
97} {1 1 {} {} | 3 3 {} {} | 4 4 {} {} |}
98
99# Bug in the ORDER BY LIMIT optimization reported on 2016-09-06.
100# Ticket https://www.sqlite.org/src/info/559733b09e96
101#
102do_execsql_test limit2-300 {
103  CREATE TABLE t300(a,b,c);
104  CREATE INDEX t300x ON t300(a,b,c);
105  INSERT INTO t300 VALUES(0,1,99),(0,1,0),(0,0,0);
106  SELECT *,'.' FROM t300 WHERE a=0 AND (c=0 OR c=99) ORDER BY c DESC;
107} {0 1 99 . 0 0 0 . 0 1 0 .}
108do_execsql_test limit2-310 {
109  SELECT *,'.' FROM t300 WHERE a=0 AND (c=0 OR c=99) ORDER BY c DESC LIMIT 1;
110} {0 1 99 .}
111
112# Make sure the SELECT loop is ordered correctly for the direction of
113# the ORDER BY
114#
115do_execsql_test limit2-400 {
116  CREATE TABLE t400(a,b);
117  CREATE INDEX t400_ab ON t400(a,b);
118  INSERT INTO t400(a,b) VALUES(1,90),(1,40),(2,80),(2,30),(3,70),(3,20);
119  SELECT *,'x' FROM t400 WHERE a IN (1,2,3) ORDER BY b DESC LIMIT 3;
120  SELECT *,'y' FROM t400 WHERE a IN (1,2,3) ORDER BY +b DESC LIMIT 3;
121} {1 90 x 2 80 x 3 70 x 1 90 y 2 80 y 3 70 y}
122
123finish_test
124