From: drh <>
Date: Wed, 2 Jun 2021 17:14:50 +0000 (+0000)
Subject: Never use WHERE_IN_SEEKSCAN for the 2nd or subsequent IN operator.
X-Git-Tag: version-3.36.0~43^2~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=eda790d28b431957fa876cafbe6526c7b128e114;p=thirdparty%2Fsqlite.git

Never use WHERE_IN_SEEKSCAN for the 2nd or subsequent IN operator.

FossilOrigin-Name: d0b98619082038ed451912bcdf56568835a8577989a25cacf25591f2366d4f52
---

diff --git a/manifest b/manifest
index 9732d15ae4..f47789bbee 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C This\sis\san\sattempt\sto\saddress\sthe\sOP_SeekScan\sperformance\sissue\sidentified\sby\n[forum:/forumpost/b4fcb8a598|forum\spost\sb4fcb8a598].
-D 2021-06-02T12:44:26.088
+C Never\suse\sWHERE_IN_SEEKSCAN\sfor\sthe\s2nd\sor\ssubsequent\sIN\soperator.
+D 2021-06-02T17:14:50.729
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -631,7 +631,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c c8ec20a1ca161d5635a4f19c2a4efec2e006e19a8a61f272bf6bce1c80ab7436
 F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c 7342becedf3f8a26f9817f08436bdf8b56ad69af83705f6b9320a0ad3092c2ac
-F src/where.c 2a6ae34252a15de5e6e1102d037ec899bd22c020d4f3e3df30f7afc1d9d3e349
+F src/where.c fbb2da2b618c4a382a803d2a68795ade50702fa1cc21cd7c5b42f48ce811050a
 F src/whereInt.h 9248161dd004f625ce5d3841ca9b99fed3fc8d61522cf76340fc5217dbe1375b
 F src/wherecode.c d0963d5a2aaae8c18f459a7e72dc6c7ca897f3a4ddb40fd56a12384b725e9e0a
 F src/whereexpr.c 5a9c9f5d2dac4bcdcaae3035034b4667523f731df228e0bb1d4efc669efa9da5
@@ -1074,7 +1074,7 @@ F test/imposter1.test c3f1db2d3db2c24611a6596a3fc0ffc14f1466c8
 F test/in.test 688ed2011d922d83141a45af431601738674a4c0bdde34b6351f688b82a169b3
 F test/in2.test 5d4c61d17493c832f7d2d32bef785119e87bde75
 F test/in3.test 3cbf58c87f4052cee3a58b37b6389777505aa0c0
-F test/in4.test cd08375ba470b248c3dc4ab30fd5dbcb682deafe3862d8249ba0ad6a11dd25ea
+F test/in4.test 3f68dd68bda673e677c561b81e71cc7a42da1f08c3e172cb2ddab6c55f505269
 F test/in5.test b32ce7f4a93f44c5dee94af16886d922cc16ebe33c8e1765c73d4049d0f4b40f
 F test/in6.test f5f40d6816a8bb7c784424b58a10ac38efb76ab29127a2c17399e0cbeeda0e4b
 F test/incrblob.test c9b96afc292aeff43d6687bcb09b0280aa599822
@@ -1918,10 +1918,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P a8d921136f8ab132279984a77d0eeaf355342cdb0a98d7e1e59c8e6c8ed9459c
-R c9d14953d90f0bc10aff723dd24fc8cd
-T *branch * seekscan-improvements
-T *sym-seekscan-improvements *
-T -sym-trunk *
+P d58efb3f21a4150b8136197e43837c7b646c42d492a7c24ddc7591dba415a2c8
+R 8ad2053968a5fcd14ddf59995bbbadeb
 U drh
-Z 37cec0fe3735838a40d15474ed3bffee
+Z 725e8b4bd380dc24d27ee8c2d8e9d784
diff --git a/manifest.uuid b/manifest.uuid
index 0ba9b1497b..cf28dca327 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d58efb3f21a4150b8136197e43837c7b646c42d492a7c24ddc7591dba415a2c8
\ No newline at end of file
+d0b98619082038ed451912bcdf56568835a8577989a25cacf25591f2366d4f52
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index 9ccdd7e669..9409495639 100644
--- a/src/where.c
+++ b/src/where.c
@@ -2627,7 +2627,7 @@ static int whereLoopAddBtreeIndex(
             ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d) "
              "prefers indexed lookup\n",
              saved_nEq, M, logK, nIn, rLogSize, x));
-        }else if( x < -nInMul ){
+        }else if( nInMul<2 ){
           WHERETRACE(0x40,
             ("IN operator (N=%d M=%d logK=%d nIn=%d rLogSize=%d x=%d"
              " nInMul=%d) prefers skip-scan\n",
diff --git a/test/in4.test b/test/in4.test
index de8c2d6dbc..fb57661208 100644
--- a/test/in4.test
+++ b/test/in4.test
@@ -392,5 +392,38 @@ do_execsql_test 8.3 {
   SELECT t1.x FROM t2 CROSS JOIN t1 WHERE t2.z = t1.y AND t1.x IN (111, 222);
 } {222 111}
 
+# 2021-06-02 forum post https://sqlite.org/forum/forumpost/b4fcb8a598
+# OP_SeekScan changes from check-in 4a43430fd23f8835 on 2020-09-30 causes
+# performance regression.
+#
+reset_db
+do_execsql_test 9.0 {
+  CREATE TABLE node(node_id INTEGER PRIMARY KEY);
+  CREATE TABLE edge(node_from INT, node_to INT);
+  CREATE TABLE sub_nodes(node_id INTEGER PRIMARY KEY);
+  CREATE INDEX edge_from_to ON edge(node_from,node_to);
+  CREATE INDEX edge_to_from ON edge(node_to,node_from);
+  ANALYZE;
+  DELETE FROM sqlite_stat1;
+  INSERT INTO sqlite_stat1 VALUES
+    ('sub_nodes',NULL,'1000000'),
+    ('edge','edge_to_from','20000000 2 2'),
+    ('edge','edge_from_to','20000000 2 2'),
+    ('node',NULL,'10000000');
+  ANALYZE sqlite_schema;
+} {}
+do_eqp_test 9.1 {
+SELECT count(*) FROM edge
+ WHERE node_from IN sub_nodes AND node_to IN sub_nodes;
+} {
+  QUERY PLAN
+  |--SEARCH edge USING COVERING INDEX edge_to_from (node_to=?)
+  |--USING ROWID SEARCH ON TABLE sub_nodes FOR IN-OPERATOR
+  `--USING ROWID SEARCH ON TABLE sub_nodes FOR IN-OPERATOR
+}
+# ^^^^^ the key to the above is that the index should only use a single
+#       term (node_to=?), not two terms (node_to=? AND node_from=).
+
+
 
 finish_test