From: drh <>
Date: Thu, 1 Sep 2022 10:29:02 +0000 (+0000)
Subject: In the query planner, add a heuristic that will reduce the cost of a full
X-Git-Tag: version-3.40.0~215
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a3fc683c80c41292b03aa89a689ee25ab987fa12;p=thirdparty%2Fsqlite.git

In the query planner, add a heuristic that will reduce the cost of a full
table scan for a materialized view or subquery if the full scan is the
outer-most loop.  This is shown to speed up some queries.

FossilOrigin-Name: 609fbb94b8f01d6792e5941ab23ce041313d359f6788c4dde6b1ca749ab49137
---

diff --git a/manifest b/manifest
index 746bbe3c38..6a1a80007e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Enhance\sthe\sb-tree\spage\ssorting\scode\sto\sensure\sthat\ssqlite3PagerRekey()\snever\noverloads\sa\spage\snumber\sand\suses\sonly\sthe\sPENDING_BYTE\spage\sfor\stemporary\nstorage.
-D 2022-08-31T15:04:42.204
+C In\sthe\squery\splanner,\sadd\sa\sheuristic\sthat\swill\sreduce\sthe\scost\sof\sa\sfull\ntable\sscan\sfor\sa\smaterialized\sview\sor\ssubquery\sif\sthe\sfull\sscan\sis\sthe\nouter-most\sloop.\s\sThis\sis\sshown\sto\sspeed\sup\ssome\squeries.
+D 2022-09-01T10:29:02.873
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -675,8 +675,8 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c b9df133a705093da8977da5eb202eaadb844839f1c7297c08d33471f5491843d
 F src/wal.h c3aa7825bfa2fe0d85bef2db94655f99870a285778baa36307c0a16da32b226a
 F src/walker.c f890a3298418d7cba3b69b8803594fdc484ea241206a8dfa99db6dd36f8cbb3b
-F src/where.c 6d1ee6f6bc048406554176eb6146b27ac16ec96cca018848aa0b9836b2b71143
-F src/whereInt.h b48ca529ffe293c18cbfa8326af18a09e39910de66fb3e96ef788c7cbf8ef3a7
+F src/where.c 424c42590b71968a9b81cd890df2671902028613fee38a50ed4c2f7ca65315d3
+F src/whereInt.h 70cd30de9ed784aa33fa6bd1245f060617de7a00d992469b6d8e419eed915743
 F src/wherecode.c 6bb1cf9d0a4e3e04dab0bf0ea4a8d936a0dcc05a7e2207beeda6c61aea6dd341
 F src/whereexpr.c 55a39f42aaf982574fbf52906371a84cceed98a994422198dfd03db4fce4cc46
 F src/window.c 928e215840e2f2d9a2746e018c9643ef42c66c4ab6630ef0df7fa388fa145e86
@@ -1852,7 +1852,7 @@ F test/win32heap.test 10fd891266bd00af68671e702317726375e5407561d859be1aa04696f2
 F test/win32lock.test e0924eb8daac02bf80e9da88930747bd44dd9b230b7759fed927b1655b467c9c
 F test/win32longpath.test 4baffc3acb2e5188a5e3a895b2b543ed09e62f7c72d713c1feebf76222fe9976
 F test/win32nolock.test ac4f08811a562e45a5755e661f45ca85892bdbbc
-F test/window1.test ae87c4ea4e689725c7e1c826ab2b10704d5b6d31f9b9e5abadded996ba53a1d4
+F test/window1.test 08bac934238ff66987635ea3367c5aed5b4c088c414441beaba426e68a8257c1
 F test/window2.tcl 492c125fa550cda1dd3555768a2303b3effbeceee215293adf8871efc25f1476
 F test/window2.test e466a88bd626d66edc3d352d7d7e1d5531e0079b549ba44efb029d1fbff9fd3c
 F test/window3.tcl acea6e86a4324a210fd608d06741010ca83ded9fde438341cb978c49928faf03
@@ -1876,7 +1876,7 @@ F test/windowfault.test 15094c1529424e62f798bc679e3fe9dfab6e8ba2f7dfe8c923b6248c
 F test/windowpushd.test d8895d08870b7226f7693665bd292eb177e62ca06799184957b3ca7dc03067df
 F test/with1.test 9ad67fdeb2bbd808a5763c9060e214ea232f9b18d846ea3a59756dc38bdc3880
 F test/with2.test a1df41b987198383b9b70bf5e5fda390582e46398653858dbc6ceb24253b28df
-F test/with3.test ad32d13ad50661e6fa305f62a0717649c348792e7b658bf2644976227a9e0373
+F test/with3.test 1e2e8d5e7b1d955342d0d18c250aaaa6e6bcf36ef2a818477bd01cb74f9a5d66
 F test/with4.test 257be66c0c67fee1defbbac0f685c3465e2cad037f21ce65f23f86084f198205
 F test/with5.test 6248213c41fab36290b5b73aa3f937309dfba337004d9d8434c3fabc8c7d4be8
 F test/with6.test c18592592b5a1c5802fd4e933d506f7b34ebbe8fdd585229793e960ae58d433f
@@ -1999,8 +1999,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P dd017bb1b3e31c7692d29dc4865d6bda871e429978c8738a39160d0114e5bf9b
-R 98122ff0aaf5ca87deda59c5c8a25251
+P 5007742886bd20de20be3973737cf46b010359911615eb3da69cd262bd9a2435
+R 5af1ce0d7f6d60d5f513975f3a1b9fe9
 U drh
-Z 8d73d18db9ab73a94a9689d17f937c1d
+Z 1d09512c855de39ee2d5b2ad872e6d10
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 00cb077051..231675a657 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-5007742886bd20de20be3973737cf46b010359911615eb3da69cd262bd9a2435
\ No newline at end of file
+609fbb94b8f01d6792e5941ab23ce041313d359f6788c4dde6b1ca749ab49137
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index 0a6f5e6273..3e90fa9a7c 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3463,6 +3463,9 @@ static int whereLoopAddBtree(
 #else
       pNew->rRun = rSize + 16;
 #endif
+      if( IsView(pTab) || (pTab->tabFlags & TF_Ephemeral)!=0 ){
+        pNew->wsFlags |= WHERE_VIEWSCAN;
+      }
       ApplyCostMultiplier(pNew->rRun, pTab->costMult);
       whereLoopOutputAdjust(pWC, pNew, rSize);
       rc = whereLoopInsert(pBuilder, pNew);
@@ -4843,6 +4846,13 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
           rUnsorted -= 2;  /* TUNING:  Slight bias in favor of no-sort plans */
         }
 
+        /* TUNING:  A full-scan of a VIEW or subquery in the outer loop
+        ** is not so bad. */
+        if( iLoop==0 && (pWLoop->wsFlags & WHERE_VIEWSCAN)!=0 ){
+          rCost += -10;
+          nOut += -30;
+        }
+
         /* Check to see if pWLoop should be added to the set of
         ** mxChoice best-so-far paths.
         **
diff --git a/src/whereInt.h b/src/whereInt.h
index bc96ff7e67..fda207890c 100644
--- a/src/whereInt.h
+++ b/src/whereInt.h
@@ -648,5 +648,6 @@ void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*);
 #define WHERE_BLOOMFILTER  0x00400000  /* Consider using a Bloom-filter */
 #define WHERE_SELFCULL     0x00800000  /* nOut reduced by extra WHERE terms */
 #define WHERE_OMIT_OFFSET  0x01000000  /* Set offset counter to zero */
+#define WHERE_VIEWSCAN     0x02000000  /* A full-scan of a VIEW or subquery */
 
 #endif /* !defined(SQLITE_WHEREINT_H) */
diff --git a/test/window1.test b/test/window1.test
index fd71ed6bb9..0f22829847 100644
--- a/test/window1.test
+++ b/test/window1.test
@@ -212,10 +212,11 @@ do_execsql_test 6.1 {
 } {1 1 2 2 3 3 4 4 5 5 6 6 7 7}
 
 do_execsql_test 6.2 {
-  SELECT * FROM t2, (SELECT x, count(*) OVER (ORDER BY x) FROM t1);
+  SELECT * FROM t2, (SELECT x, count(*) OVER (ORDER BY x) FROM t1)
+  ORDER BY 1, 2;
 } {
-  b 1 1 b 2 2 b 3 3 b 4 4 b 5 5 b 6 6 b 7 7
   a 1 1 a 2 2 a 3 3 a 4 4 a 5 5 a 6 6 a 7 7
+  b 1 1 b 2 2 b 3 3 b 4 4 b 5 5 b 6 6 b 7 7
 }
 
 do_catchsql_test 6.3 {
diff --git a/test/with3.test b/test/with3.test
index 8e8eba89f6..1aed92a99a 100644
--- a/test/with3.test
+++ b/test/with3.test
@@ -131,8 +131,8 @@ do_eqp_test 3.2.2 {
   |  |  `--SCALAR SUBQUERY xxxxxx
   |  |     `--SCAN w2
   |  `--RECURSIVE STEP
-  |     |--SCAN w1
-  |     `--SCAN c
+  |     |--SCAN c
+  |     `--SCAN w1
   |--SCAN c
   |--SEARCH w2 USING INTEGER PRIMARY KEY (rowid=?)
   `--SEARCH w1 USING INTEGER PRIMARY KEY (rowid=?)