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https://sqlite.org/forum/forumpost/3a180ba0d4 and https://sqlite.org/forum/forumpost/f9346b11a6
https://sqlite.org/src/info/aa6bd6dff751223e
(-> https://sqlite.org/src/vpatch?from=71215599cd8ebb97&to=aa6bd6dff751223e)
--- a/src/select.c
+++ b/src/select.c
@@ -4236,12 +4236,11 @@
** (17f) the subquery must not be the RHS of a LEFT JOIN.
** (17g) either the subquery is the first element of the outer
** query or there are no RIGHT or FULL JOINs in any arm
** of the subquery. (This is a duplicate of condition (27b).)
** (17h) The corresponding result set expressions in all arms of the
-** compound must have the same affinity. (See restriction (9)
-** on the push-down optimization.)
+** compound must have the same affinity.
**
** The parent and sub-query may contain WHERE clauses. Subject to
** rules (11), (13) and (14), they may also contain ORDER BY,
** LIMIT and OFFSET clauses. The subquery cannot use any compound
** operator other than UNION ALL because all the other compound
@@ -5105,14 +5104,10 @@
**
** (8) If the subquery is a compound that uses UNION, INTERSECT,
** or EXCEPT, then all of the result set columns for all arms of
** the compound must use the BINARY collating sequence.
**
-** (9) If the subquery is a compound, then all arms of the compound must
-** have the same affinity. (This is the same as restriction (17h)
-** for query flattening.)
-**
**
** Return 0 if no changes are made and non-zero if one or more WHERE clause
** terms are duplicated into the subquery.
*/
static int pushDownWhereTerms(
@@ -5139,13 +5134,10 @@
}
#ifndef SQLITE_OMIT_WINDOWFUNC
if( pSel->pWin ) return 0; /* restriction (6b) */
#endif
}
- if( compoundHasDifferentAffinities(pSubq) ){
- return 0; /* restriction (9) */
- }
if( notUnionAll ){
/* If any of the compound arms are connected using UNION, INTERSECT,
** or EXCEPT, then we must ensure that none of the columns use a
** non-BINARY collating sequence. */
for(pSel=pSubq; pSel; pSel=pSel->pPrior){
--- a/test/pushdown.test
+++ b/test/pushdown.test
@@ -120,7 +120,47 @@
SELECT v1.a, v1.b, t0.c0 AS cd FROM t0 LEFT JOIN v0 ON v0.c0!=0, v1
) WHERE a=2 AND b=0 AND cd=0;
} {
2 0 0
}
-
+
+# 2023-02-22 https://sqlite.org/forum/forumpost/bcc4375032
+# Performance regression caused by check-in [1ad41840c5e0fa70] from 2022-11-25.
+# That check-in added a new restriction on push-down. The new restriction is
+# no longer necessary after check-in [27655c9353620aa5] from 2022-12-14.
+#
+do_execsql_test 3.5 {
+ DROP TABLE IF EXISTS t1;
+ CREATE TABLE t1(a INT, b INT, c TEXT, PRIMARY KEY(a,b)) WITHOUT ROWID;
+ INSERT INTO t1(a,b,c) VALUES
+ (1,100,'abc'),
+ (2,200,'def'),
+ (3,300,'abc');
+ DROP TABLE IF EXISTS t2;
+ CREATE TABLE t2(a INT, b INT, c TEXT, PRIMARY KEY(a,b)) WITHOUT ROWID;
+ INSERT INTO t2(a,b,c) VALUES
+ (1,110,'efg'),
+ (2,200,'hij'),
+ (3,330,'klm');
+ CREATE VIEW v3 AS
+ SELECT a, b, c FROM t1
+ UNION ALL
+ SELECT a, b, 'xyz' FROM t2;
+ SELECT * FROM v3 WHERE a=2 AND b=200;
+} {2 200 def 2 200 xyz}
+do_eqp_test 3.6 {
+ SELECT * FROM v3 WHERE a=2 AND b=200;
+} {
+ QUERY PLAN
+ |--CO-ROUTINE v3
+ | `--COMPOUND QUERY
+ | |--LEFT-MOST SUBQUERY
+ | | `--SEARCH t1 USING PRIMARY KEY (a=? AND b=?)
+ | `--UNION ALL
+ | `--SEARCH t2 USING PRIMARY KEY (a=? AND b=?)
+ `--SCAN v3
+}
+# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+# We want both arms of the compound subquery to use the
+# primary key.
+
finish_test
|
