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