# 2016 March 3 # # 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. # #*********************************************************************** set testdir [file dirname $argv0] source $testdir/tester.tcl set testprefix bestindex2 ifcapable !vtab { finish_test return } #------------------------------------------------------------------------- # Virtual table callback for table named $tbl, with the columns specified # by list argument $cols. e.g. if the function is invoked as: # # vtab_cmd t1 {a b c} ... # # The table created is: # # "CREATE TABLE t1 (a, b, c)" # # The tables xBestIndex method behaves as if all possible combinations of # "=" constraints (but no others) may be optimized. The cost of a full table # scan is: # # "WHERE 1" "cost 1000000 rows 1000000" # # If one or more "=" constraints are in use, the cost and estimated number # of rows returned are both is (11 - nCons)*1000, where nCons is the number # of constraints used. e.g. # # "WHERE a=? AND b=?" -> "cost 900 rows 900" # "WHERE c=? AND b "cost 1000 rows 1000" # proc vtab_cmd {tbl cols method args} { switch -- $method { xConnect { return "CREATE TABLE $tbl ([join $cols ,])" } xBestIndex { foreach {clist orderby mask} $args {} set cons [list] set used [list] for {set i 0} {$i < [llength $clist]} {incr i} { array unset C array set C [lindex $clist $i] if {$C(op)=="eq" && $C(usable) && [lsearch $cons $C(column)]<0} { lappend used use $i lappend cons $C(column) } } set nCons [llength $cons] if {$nCons==0} { return "cost 1000000 rows 1000000" } else { set cost [expr (11-$nCons) * 1000] set ret [concat $used "cost $cost rows $cost"] set txt [list] foreach c $cons { lappend txt "[lindex $cols $c]=?" } lappend ret idxstr "indexed([join $txt { AND }])" return $ret } } } return "" } register_tcl_module db do_execsql_test 1.0 { CREATE VIRTUAL TABLE t1 USING tcl("vtab_cmd t1 {a b}"); CREATE VIRTUAL TABLE t2 USING tcl("vtab_cmd t2 {c d}"); CREATE VIRTUAL TABLE t3 USING tcl("vtab_cmd t3 {e f}"); } do_eqp_test 1.1 { SELECT * FROM t1 WHERE a='abc' } { 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:indexed(a=?)} } do_eqp_test 1.2 { SELECT * FROM t1 WHERE a='abc' AND b='def' } { 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:indexed(a=? AND b=?)} } do_eqp_test 1.3 { SELECT * FROM t1 WHERE a='abc' AND a='def' } { 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:indexed(a=?)} } do_eqp_test 1.4 { SELECT * FROM t1,t2 WHERE c=a } { 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:} 0 1 1 {SCAN TABLE t2 VIRTUAL TABLE INDEX 0:indexed(c=?)} } do_eqp_test 1.5 { SELECT * FROM t1, t2 CROSS JOIN t3 WHERE t2.c = +t1.b AND t3.e=t2.d } { 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:} 0 1 1 {SCAN TABLE t2 VIRTUAL TABLE INDEX 0:indexed(c=?)} 0 2 2 {SCAN TABLE t3 VIRTUAL TABLE INDEX 0:indexed(e=?)} } do_eqp_test 1.6 { SELECT * FROM t1, t2, t3 WHERE t2.c = +t1.b AND t3.e = t2.d } { 0 0 0 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:} 0 1 1 {SCAN TABLE t2 VIRTUAL TABLE INDEX 0:indexed(c=?)} 0 2 2 {SCAN TABLE t3 VIRTUAL TABLE INDEX 0:indexed(e=?)} } do_execsql_test 1.7.1 { CREATE TABLE x1(a, b); } do_eqp_test 1.7.2 { SELECT * FROM x1 CROSS JOIN t1, t2, t3 WHERE t1.a = t2.c AND t1.b = t3.e } { 0 0 0 {SCAN TABLE x1} 0 1 1 {SCAN TABLE t1 VIRTUAL TABLE INDEX 0:} 0 2 2 {SCAN TABLE t2 VIRTUAL TABLE INDEX 0:indexed(c=?)} 0 3 3 {SCAN TABLE t3 VIRTUAL TABLE INDEX 0:indexed(e=?)} } finish_test