AryaWu/sqlite

1# 2016 March 32#3# The author disclaims copyright to this source code.  In place of4# 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 12set testdir [file dirname $argv0]13source $testdir/tester.tcl14set testprefix bestindex215 16ifcapable !vtab {17  finish_test18  return19}20 21#-------------------------------------------------------------------------22# Virtual table callback for table named $tbl, with the columns specified23# by list argument $cols. e.g. if the function is invoked as:24#25#   vtab_cmd t1 {a b c} ...26#27# The table created is:28#29#      "CREATE TABLE t1 (a, b, c)"30#31# The tables xBestIndex method behaves as if all possible combinations of32# "=" constraints (but no others) may be optimized. The cost of a full table33# scan is:34#35#      "WHERE 1"                "cost 1000000 rows 1000000"36#37# If one or more "=" constraints are in use, the cost and estimated number38# of rows returned are both is (11 - nCons)*1000, where nCons is the number39# of constraints used. e.g.40#41#   "WHERE a=? AND b=?"    ->   "cost  900 rows  900"42#   "WHERE c=? AND b<?"    ->   "cost 1000 rows 1000"43#  44proc vtab_cmd {tbl cols method args} {45  switch -- $method {46    xConnect {47      return "CREATE TABLE $tbl ([join $cols ,])"48    }49    xBestIndex {50      set hdl [lindex $args 0]51      set clist [$hdl constraints]52      set orderby [$hdl orderby]53      set mask [$hdl mask]54 55      set cons [list]56      set used [list]57 58      for {set i 0} {$i < [llength $clist]} {incr i} {59        array unset C60        array set C [lindex $clist $i]61        if {$C(op)=="eq" && $C(usable) && [lsearch $cons $C(column)]<0} {62          lappend used use $i63          lappend cons $C(column)64        }65      }66 67      set nCons [llength $cons]68      if {$nCons==0} {69        return "cost 1000000 rows 1000000"70      } else {71        set cost [expr (11-$nCons) * 1000]72        set ret [concat $used "cost $cost rows $cost"]73 74        set txt [list]75        foreach c $cons { lappend txt "[lindex $cols $c]=?" }76        lappend ret idxstr "indexed([join $txt { AND }])"77 78        return $ret79      }80    }81  }82  return ""83}84 85register_tcl_module db86 87do_execsql_test 1.0 {88  CREATE VIRTUAL TABLE t1 USING tcl("vtab_cmd t1 {a b}");89  CREATE VIRTUAL TABLE t2 USING tcl("vtab_cmd t2 {c d}");90  CREATE VIRTUAL TABLE t3 USING tcl("vtab_cmd t3 {e f}");91}92 93do_eqp_test 1.1 {94  SELECT * FROM t1 WHERE a='abc'95} {SCAN t1 VIRTUAL TABLE INDEX 0:indexed(a=?)}96 97do_eqp_test 1.2 {98  SELECT * FROM t1 WHERE a='abc' AND b='def'99} {SCAN t1 VIRTUAL TABLE INDEX 0:indexed(a=? AND b=?)}100 101do_eqp_test 1.3 {102  SELECT * FROM t1 WHERE a='abc' AND a='def'103} {SCAN t1 VIRTUAL TABLE INDEX 0:indexed(a=?)}104 105do_eqp_test 1.4 {106  SELECT * FROM t1,t2 WHERE c=a107} {108  QUERY PLAN109  |--SCAN t1 VIRTUAL TABLE INDEX 0:110  `--SCAN t2 VIRTUAL TABLE INDEX 0:indexed(c=?)111}112 113do_eqp_test 1.5 {114  SELECT * FROM t1, t2 CROSS JOIN t3 WHERE t2.c = +t1.b AND t3.e=t2.d115} {116  QUERY PLAN117  |--SCAN t1 VIRTUAL TABLE INDEX 0:118  |--SCAN t2 VIRTUAL TABLE INDEX 0:indexed(c=?)119  `--SCAN t3 VIRTUAL TABLE INDEX 0:indexed(e=?)120}121 122do_eqp_test 1.6 {123  SELECT * FROM t1, t2, t3 WHERE t2.c = +t1.b AND t3.e = t2.d124} {125  QUERY PLAN126  |--SCAN t1 VIRTUAL TABLE INDEX 0:127  |--SCAN t2 VIRTUAL TABLE INDEX 0:indexed(c=?)128  `--SCAN t3 VIRTUAL TABLE INDEX 0:indexed(e=?)129}130 131do_execsql_test 1.7.1 {132  CREATE TABLE x1(a, b);133}134do_eqp_test 1.7.2 {135  SELECT * FROM x1 CROSS JOIN t1, t2, t3 136    WHERE t1.a = t2.c AND t1.b = t3.e137} {138  QUERY PLAN139  |--SCAN x1140  |--SCAN t1 VIRTUAL TABLE INDEX 0:141  |--SCAN t2 VIRTUAL TABLE INDEX 0:indexed(c=?)142  `--SCAN t3 VIRTUAL TABLE INDEX 0:indexed(e=?)143}144 145finish_test146