f43ffb30b0
EXPLAIN QUERY PLAN output. FossilOrigin-Name: d7b2ac1c1a31fa4285cf6df0995db7e7705bb6a1bc94850c14c94cc4e3eb239a
95 lines
2.9 KiB
Plaintext
95 lines
2.9 KiB
Plaintext
# 2014-06-17
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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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# This file implements regression tests for SQLite library. The
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# focus of this script is testing automatic index creation logic,
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# and specifically that an automatic index will not be created that
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# shadows a declared index.
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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 autoindex3
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# The t1b and t2d indexes are not very selective. It used to be that
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# the autoindex mechanism would create automatic indexes on t1(b) or
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# t2(d), make assumptions that they were reasonably selective, and use
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# them instead of t1b or t2d. But that would be cheating, because the
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# automatic index cannot be any more selective than the real index.
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#
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# This test verifies that the cheat is no longer allowed.
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#
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do_execsql_test autoindex3-100 {
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CREATE TABLE t1(a,b,x);
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CREATE TABLE t2(c,d,y);
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CREATE INDEX t1b ON t1(b);
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CREATE INDEX t2d ON t2(d);
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ANALYZE sqlite_master;
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INSERT INTO sqlite_stat1 VALUES('t1','t1b','10000 500');
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INSERT INTO sqlite_stat1 VALUES('t2','t2d','10000 500');
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ANALYZE sqlite_master;
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EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d=b;
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} {~/AUTO/}
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# Automatic indexes can still be used if existing indexes do not
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# participate in == constraints.
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#
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do_execsql_test autoindex3-110 {
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EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d>b AND x=y;
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} {/AUTO/}
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do_execsql_test autoindex3-120 {
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EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d<b AND x=y;
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} {/AUTO/}
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do_execsql_test autoindex3-130 {
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EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d IS NULL AND x=y;
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} {/AUTO/}
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do_execsql_test autoindex3-140 {
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EXPLAIN QUERY PLAN SELECT * FROM t1, t2 WHERE d IN (5,b) AND x=y;
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} {/AUTO/}
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reset_db
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do_execsql_test 210 {
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CREATE TABLE v(b, d, e);
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CREATE TABLE u(a, b, c);
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ANALYZE sqlite_master;
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INSERT INTO "sqlite_stat1" VALUES('u','uab','40000 400 1');
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INSERT INTO "sqlite_stat1" VALUES('v','vbde','40000 400 1 1');
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INSERT INTO "sqlite_stat1" VALUES('v','ve','40000 21');
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CREATE INDEX uab on u(a, b);
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CREATE INDEX ve on v(e);
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CREATE INDEX vbde on v(b,d,e);
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DROP TABLE IF EXISTS sqlite_stat4;
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ANALYZE sqlite_master;
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}
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# At one point, SQLite was using the inferior plan:
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#
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# 0|0|1|SEARCH v USING INDEX ve (e>?)
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# 0|1|0|SEARCH u USING COVERING INDEX uab (ANY(a) AND b=?)
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#
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# on the basis that the real index "uab" must be better than the automatic
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# index. This is not right - a skip-scan is not necessarily better than an
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# automatic index scan.
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#
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do_eqp_test 220 {
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select count(*) from u, v where u.b = v.b and v.e > 34;
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} {
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QUERY PLAN
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|--SEARCH v USING INDEX ve (e>?)
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|--BLOOM FILTER ON u (b=?)
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`--SEARCH u USING AUTOMATIC COVERING INDEX (b=?)
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}
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finish_test
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