94 lines
2.1 KiB
Plaintext
94 lines
2.1 KiB
Plaintext
# 2012 September 17
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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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#
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# Tests for the optimization which attempts to use a covering index
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# for a full-table scan (under the theory that the index will be smaller
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# and require less I/O and hence will run faster.)
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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 coveridxscan
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do_test 1.1 {
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db eval {
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CREATE TABLE t1(a,b,c);
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INSERT INTO t1 VALUES(5,4,3), (4,8,2), (3,2,1);
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CREATE INDEX t1ab ON t1(a,b);
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CREATE INDEX t1b ON t1(b);
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SELECT a FROM t1;
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}
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# covering index used for the scan, hence values are increasing
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} {3 4 5}
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do_test 1.2 {
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db eval {
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SELECT a, c FROM t1;
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}
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# There is no covering index, hence the values are in rowid order
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} {5 3 4 2 3 1}
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do_test 1.3 {
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db eval {
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SELECT b FROM t1;
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}
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# Choice of two indices: use the one with fewest columns
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} {2 4 8}
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do_test 2.1 {
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optimization_control db cover-idx-scan 0
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db eval {SELECT a FROM t1}
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# With the optimization turned off, output in rowid order
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} {5 4 3}
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do_test 2.2 {
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db eval {SELECT a, c FROM t1}
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} {5 3 4 2 3 1}
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do_test 2.3 {
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db eval {SELECT b FROM t1}
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} {4 8 2}
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db close
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sqlite3_shutdown
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sqlite3_config_cis 0
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sqlite3 db test.db
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do_test 3.1 {
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db eval {SELECT a FROM t1}
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# With the optimization configured off, output in rowid order
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} {5 4 3}
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do_test 3.2 {
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db eval {SELECT a, c FROM t1}
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} {5 3 4 2 3 1}
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do_test 3.3 {
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db eval {SELECT b FROM t1}
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} {4 8 2}
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db close
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sqlite3_shutdown
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sqlite3_config_cis 1
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sqlite3 db test.db
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# The CIS optimization is enabled again. Covering indices are once again
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# used for all table scans.
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do_test 4.1 {
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db eval {SELECT a FROM t1}
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} {3 4 5}
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do_test 4.2 {
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db eval {SELECT a, c FROM t1}
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} {5 3 4 2 3 1}
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do_test 4.3 {
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db eval {SELECT b FROM t1}
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} {2 4 8}
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finish_test
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