mirror of
https://github.com/sqlite/sqlite.git
synced 2024-11-25 08:59:33 +01:00
85 lines
2.2 KiB
Plaintext
85 lines
2.2 KiB
Plaintext
# 2020-02-23
|
|
#
|
|
# 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.
|
|
#
|
|
#***********************************************************************
|
|
# Tests for functionality related to ANALYZE.
|
|
#
|
|
|
|
set testdir [file dirname $argv0]
|
|
source $testdir/tester.tcl
|
|
|
|
ifcapable !stat4 {
|
|
finish_test
|
|
return
|
|
}
|
|
set testprefix analyzeG
|
|
|
|
#-------------------------------------------------------------------------
|
|
# Test cases 1.* seek to verify that even if an index is not used, its
|
|
# stat4 data may be used by the planner to estimate the number of
|
|
# rows that match an unindexed constraint on the same column.
|
|
#
|
|
do_execsql_test 1.0 {
|
|
PRAGMA automatic_index = 0;
|
|
CREATE TABLE t1(a, x);
|
|
CREATE TABLE t2(b, y);
|
|
WITH s(i) AS (
|
|
SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
|
|
)
|
|
INSERT INTO t1 SELECT (i%50), NULL FROM s;
|
|
WITH s(i) AS (
|
|
SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<100
|
|
)
|
|
INSERT INTO t2 SELECT (CASE WHEN i<95 THEN 44 ELSE i END), NULL FROM s;
|
|
}
|
|
|
|
# Join tables t1 and t2. Both contain 100 rows. (a=44) matches 2 rows
|
|
# in "t1", (b=44) matches 95 rows in table "t2". But the planner doesn't
|
|
# know this, so it has no preference as to which order the tables are
|
|
# scanned in. In practice this means that tables are scanned in the order
|
|
# they are specified in in the FROM clause.
|
|
do_eqp_test 1.1.1 {
|
|
SELECT * FROM t1, t2 WHERE a=44 AND b=44;
|
|
} {
|
|
|
|
}
|
|
do_eqp_test 1.1.2 {
|
|
SELECT * FROM t2, t1 WHERE a=44 AND b=44
|
|
} {
|
|
QUERY PLAN
|
|
|--SCAN t2
|
|
`--SCAN t1
|
|
}
|
|
|
|
do_execsql_test 1.2 {
|
|
CREATE INDEX t2b ON t2(b);
|
|
ANALYZE;
|
|
}
|
|
|
|
# Now, with the ANALYZE data, the planner knows that (b=44) matches a
|
|
# large number of rows. So it elects to scan table "t1" first, regardless
|
|
# of the order in which the tables are specified in the FROM clause.
|
|
do_eqp_test 1.3.1 {
|
|
SELECT * FROM t1, t2 WHERE a=44 AND b=44;
|
|
} {
|
|
QUERY PLAN
|
|
|--SCAN t1
|
|
`--SCAN t2
|
|
}
|
|
do_eqp_test 1.3.2 {
|
|
SELECT * FROM t2, t1 WHERE a=44 AND b=44
|
|
} {
|
|
QUERY PLAN
|
|
|--SCAN t1
|
|
`--SCAN t2
|
|
}
|
|
|
|
|
|
finish_test
|