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| 1 # 2011 August 13 | |
| 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 tests for SQLite library. The focus of the tests | |
| 13 # in this file is testing the capabilities of sqlite_stat3. | |
| 14 # | |
| 15 | |
| 16 set testdir [file dirname $argv0] | |
| 17 source $testdir/tester.tcl | |
| 18 | |
| 19 ifcapable !stat4&&!stat3 { | |
| 20 finish_test | |
| 21 return | |
| 22 } | |
| 23 | |
| 24 set testprefix analyze8 | |
| 25 | |
| 26 proc eqp {sql {db db}} { | |
| 27 uplevel execsql [list "EXPLAIN QUERY PLAN $sql"] $db | |
| 28 } | |
| 29 | |
| 30 # Scenario: | |
| 31 # | |
| 32 # Two indices. One has mostly singleton entries, but for a few | |
| 33 # values there are hundreds of entries. The other has 10-20 | |
| 34 # entries per value. | |
| 35 # | |
| 36 # Verify that the query planner chooses the first index for the singleton | |
| 37 # entries and the second index for the others. | |
| 38 # | |
| 39 do_test 1.0 { | |
| 40 db eval { | |
| 41 CREATE TABLE t1(a,b,c,d); | |
| 42 CREATE INDEX t1a ON t1(a); | |
| 43 CREATE INDEX t1b ON t1(b); | |
| 44 CREATE INDEX t1c ON t1(c); | |
| 45 } | |
| 46 for {set i 0} {$i<1000} {incr i} { | |
| 47 if {$i%2==0} {set a $i} {set a [expr {($i%8)*100}]} | |
| 48 set b [expr {$i/10}] | |
| 49 set c [expr {$i/8}] | |
| 50 set c [expr {$c*$c*$c}] | |
| 51 db eval {INSERT INTO t1 VALUES($a,$b,$c,$i)} | |
| 52 } | |
| 53 db eval {ANALYZE} | |
| 54 } {} | |
| 55 | |
| 56 # The a==100 comparison is expensive because there are many rows | |
| 57 # with a==100. And so for those cases, choose the t1b index. | |
| 58 # | |
| 59 # Buf ro a==99 and a==101, there are far fewer rows so choose | |
| 60 # the t1a index. | |
| 61 # | |
| 62 do_test 1.1 { | |
| 63 eqp {SELECT * FROM t1 WHERE a=100 AND b=55} | |
| 64 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?)}} | |
| 65 do_test 1.2 { | |
| 66 eqp {SELECT * FROM t1 WHERE a=99 AND b=55} | |
| 67 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?)}} | |
| 68 do_test 1.3 { | |
| 69 eqp {SELECT * FROM t1 WHERE a=101 AND b=55} | |
| 70 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?)}} | |
| 71 do_test 1.4 { | |
| 72 eqp {SELECT * FROM t1 WHERE a=100 AND b=56} | |
| 73 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b=?)}} | |
| 74 do_test 1.5 { | |
| 75 eqp {SELECT * FROM t1 WHERE a=99 AND b=56} | |
| 76 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?)}} | |
| 77 do_test 1.6 { | |
| 78 eqp {SELECT * FROM t1 WHERE a=101 AND b=56} | |
| 79 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?)}} | |
| 80 do_test 2.1 { | |
| 81 eqp {SELECT * FROM t1 WHERE a=100 AND b BETWEEN 50 AND 54} | |
| 82 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b>? AND b<?)}} | |
| 83 | |
| 84 # There are many more values of c between 0 and 100000 than there are | |
| 85 # between 800000 and 900000. So t1c is more selective for the latter | |
| 86 # range. | |
| 87 # | |
| 88 # Test 3.2 is a little unstable. It depends on the planner estimating | |
| 89 # that (b BETWEEN 30 AND 34) will match more rows than (c BETWEEN | |
| 90 # 800000 AND 900000). Which is a pretty close call (50 vs. 32), so | |
| 91 # the planner could get it wrong with an unlucky set of samples. This | |
| 92 # case happens to work, but others ("b BETWEEN 40 AND 44" for example) | |
| 93 # will fail. | |
| 94 # | |
| 95 do_execsql_test 3.0 { | |
| 96 SELECT count(*) FROM t1 WHERE b BETWEEN 30 AND 34; | |
| 97 SELECT count(*) FROM t1 WHERE c BETWEEN 0 AND 100000; | |
| 98 SELECT count(*) FROM t1 WHERE c BETWEEN 800000 AND 900000; | |
| 99 } {50 376 32} | |
| 100 do_test 3.1 { | |
| 101 eqp {SELECT * FROM t1 WHERE b BETWEEN 30 AND 34 AND c BETWEEN 0 AND 100000} | |
| 102 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1b (b>? AND b<?)}} | |
| 103 do_test 3.2 { | |
| 104 eqp {SELECT * FROM t1 | |
| 105 WHERE b BETWEEN 30 AND 34 AND c BETWEEN 800000 AND 900000} | |
| 106 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1c (c>? AND c<?)}} | |
| 107 do_test 3.3 { | |
| 108 eqp {SELECT * FROM t1 WHERE a=100 AND c BETWEEN 0 AND 100000} | |
| 109 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1a (a=?)}} | |
| 110 do_test 3.4 { | |
| 111 eqp {SELECT * FROM t1 | |
| 112 WHERE a=100 AND c BETWEEN 800000 AND 900000} | |
| 113 } {0 0 0 {SEARCH TABLE t1 USING INDEX t1c (c>? AND c<?)}} | |
| 114 | |
| 115 finish_test | |
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