sqlite/test/tkt-385a5b56b9.test
drh 3f4d1d1b02 Attempt to use a covering index even on a full table scan, under the theory
that the index will be smaller and require less disk I/O and thus be faster.

FossilOrigin-Name: cfaa7bc12847a7006ccc93815f2395ad5259744a
2012-09-15 18:45:54 +00:00

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# 2012 April 02
#
# 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.
#
#***********************************************************************
# The tests in this file were used while developing the SQLite 4 code.
#
set testdir [file dirname $argv0]
source $testdir/tester.tcl
set testprefix tkt-385a5b56b9
do_execsql_test 1.0 {
CREATE TABLE t1(x, y);
INSERT INTO t1 VALUES(1, NULL);
INSERT INTO t1 VALUES(2, NULL);
INSERT INTO t1 VALUES(1, NULL);
}
do_execsql_test 1.1 { SELECT DISTINCT x, y FROM t1 } {1 {} 2 {}}
do_execsql_test 1.2 { CREATE UNIQUE INDEX i1 ON t1(x, y) }
do_execsql_test 1.3 { SELECT DISTINCT x, y FROM t1 } {1 {} 2 {}}
#-------------------------------------------------------------------------
do_execsql_test 2.0 {
CREATE TABLE t2(x, y NOT NULL);
CREATE UNIQUE INDEX t2x ON t2(x);
CREATE UNIQUE INDEX t2y ON t2(y);
}
do_eqp_test 2.1 { SELECT DISTINCT x FROM t2 } {
0 0 0 {SCAN TABLE t2 USING COVERING INDEX t2x (~1000000 rows)}
}
do_eqp_test 2.2 { SELECT DISTINCT y FROM t2 } {
0 0 0 {SCAN TABLE t2 USING COVERING INDEX t2y (~1000000 rows)}
}
do_eqp_test 2.3 { SELECT DISTINCT x, y FROM t2 WHERE y=10 } {
0 0 0 {SEARCH TABLE t2 USING INDEX t2y (y=?) (~1 rows)}
}
do_eqp_test 2.4 { SELECT DISTINCT x, y FROM t2 WHERE x=10 } {
0 0 0 {SEARCH TABLE t2 USING INDEX t2x (x=?) (~1 rows)}
}
finish_test