gitlab.com/CoiaPrant/sqlite3@v1.19.1/testdata/tcl/autoindex3.test (about) 1 # 2014-06-17 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 # 12 # This file implements regression tests for SQLite library. The 13 # focus of this script is testing automatic index creation logic, 14 # and specifically that an automatic index will not be created that 15 # shadows a declared index. 16 # 17 18 set testdir [file dirname $argv0] 19 source $testdir/tester.tcl 20 set testprefix autoindex3 21 22 # The t1b and t2d indexes are not very selective. It used to be that 23 # the autoindex mechanism would create automatic indexes on t1(b) or 24 # t2(d), make assumptions that they were reasonably selective, and use 25 # them instead of t1b or t2d. But that would be cheating, because the 26 # automatic index cannot be any more selective than the real index. 27 # 28 # This test verifies that the cheat is no longer allowed. 29 # 30 do_execsql_test autoindex3-100 { 31 CREATE TABLE t1(a,b,x); 32 CREATE TABLE t2(c,d,y); 33 CREATE INDEX t1b ON t1(b); 34 CREATE INDEX t2d ON t2(d); 35 ANALYZE sqlite_master; 36 INSERT INTO sqlite_stat1 VALUES('t1','t1b','10000 500'); 37 INSERT INTO sqlite_stat1 VALUES('t2','t2d','10000 500'); 38 ANALYZE sqlite_master; 39 EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d=b; 40 } {~/AUTO/} 41 42 # Automatic indexes can still be used if existing indexes do not 43 # participate in == constraints. 44 # 45 do_execsql_test autoindex3-110 { 46 EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d>b AND x=y; 47 } {/AUTO/} 48 do_execsql_test autoindex3-120 { 49 EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d<b AND x=y; 50 } {/AUTO/} 51 do_execsql_test autoindex3-130 { 52 EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d IS NULL AND x=y; 53 } {/AUTO/} 54 do_execsql_test autoindex3-140 { 55 EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d IN (5,b) AND x=y; 56 } {/AUTO/} 57 58 reset_db 59 do_execsql_test 210 { 60 CREATE TABLE v(b, d, e); 61 CREATE TABLE u(a, b, c); 62 ANALYZE sqlite_master; 63 INSERT INTO "sqlite_stat1" VALUES('u','uab','40000 400 1'); 64 INSERT INTO "sqlite_stat1" VALUES('v','vbde','40000 400 1 1'); 65 INSERT INTO "sqlite_stat1" VALUES('v','ve','40000 21'); 66 67 CREATE INDEX uab on u(a, b); 68 CREATE INDEX ve on v(e); 69 CREATE INDEX vbde on v(b,d,e); 70 71 DROP TABLE IF EXISTS sqlite_stat4; 72 ANALYZE sqlite_master; 73 } 74 75 # At one point, SQLite was using the inferior plan: 76 # 77 # 0|0|1|SEARCH v USING INDEX ve (e>?) 78 # 0|1|0|SEARCH u USING COVERING INDEX uab (ANY(a) AND b=?) 79 # 80 # on the basis that the real index "uab" must be better than the automatic 81 # index. This is not right - a skip-scan is not necessarily better than an 82 # automatic index scan. 83 # 84 do_eqp_test 220 { 85 select count(*) from u, v where u.b = v.b and v.e > 34; 86 } { 87 QUERY PLAN 88 |--SEARCH v USING INDEX ve (e>?) 89 `--SEARCH u USING AUTOMATIC COVERING INDEX (b=?) 90 } 91 92 93 finish_test