From 62be2dc753b56629cf31b1d3d502edc00f768005 Mon Sep 17 00:00:00 2001
From: dan <dan@noemail.net>
Date: Sat, 23 Nov 2019 15:10:28 +0000
Subject: [PATCH] Avoid evaluating PARTITION BY or ORDER BY expressions
 multiple times for window function queries that use multiple window functions
 with the same window-definition.

FossilOrigin-Name: 57070c68bbe15fc1d19a765182432e844c082909bdbc63b58fd86b96e2c521dd
---
 manifest          | 17 ++++++++---------
 manifest.uuid     |  2 +-
 src/window.c      | 18 +++++++++++++++---
 test/window1.test | 16 ++++++++++++++++
 4 files changed, 40 insertions(+), 13 deletions(-)

diff --git a/manifest b/manifest
index a0c3b95975..e3f8ef8d8e 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Enhance\sthe\spath\sarguments\sin\sJSON\sfunctions\sto\saccess\s"#-N"\sarray\sindexes.
-D 2019-11-23T08:51:21.228
+C Avoid\sevaluating\sPARTITION\sBY\sor\sORDER\sBY\sexpressions\smultiple\stimes\sfor\swindow\sfunction\squeries\sthat\suse\smultiple\swindow\sfunctions\swith\sthe\ssame\swindow-definition.
+D 2019-11-23T15:10:28.586
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -616,7 +616,7 @@ F src/where.c 874845fb5d93b3bc07123df8fee805e9650bd091e3ed62988273c7e2141ab8bd
 F src/whereInt.h 4a296fd4fa79fdcbc2b5e8c1b898901617655811223e1082b899c23ecb092217
 F src/wherecode.c 909325b98d5cb313f24e5c8cb304a3e3c73ca6631cdb19cfa1f580dde182fedb
 F src/whereexpr.c 39b6a538804c6e1248c22b33e09d00f89ae6a099c849c4d841ce3995562287b4
-F src/window.c b5bed964a04c23fa335d6b1d2d8011ed518b36b692c1a999ae1777a023a45e1d
+F src/window.c 35148e95bbc39c8bf0ae356096817188caa3657b9a0de516bd479451bb5b914c
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test ce1aafc86e110685b324e9a763eab4f2a73f737842ec3b687bd965867de90627
 F test/affinity3.test 6a101af2fc945ce2912f6fe54dd646018551710d
@@ -1712,7 +1712,7 @@ F test/win32heap.test 10fd891266bd00af68671e702317726375e5407561d859be1aa04696f2
 F test/win32lock.test fbf107c91d8f5512be5a5b87c4c42ab9fdd54972
 F test/win32longpath.test 169c75a3b2e43481f4a62122510210c67b08f26d
 F test/win32nolock.test ac4f08811a562e45a5755e661f45ca85892bdbbc
-F test/window1.test 60ba11fb64122c57dfd423a5f9483fb446cc27ed5cf5526152a0decdc9a761fa
+F test/window1.test 027053b78dea6ce6e4cecf8c9af79b6c44758f71bebf065c933fe75993e72994
 F test/window2.tcl 66db96fd9fd202bc31ee7f8ce7904cb469564864cff3f74e009bfef8102333f4
 F test/window2.test af2a001ded703bb8f2474fb0edfef170d5aba00f5c1f2aa9f65935b5da13df90
 F test/window3.tcl acea6e86a4324a210fd608d06741010ca83ded9fde438341cb978c49928faf03
@@ -1851,8 +1851,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P de6637e15d95b7aee2caea8b8d5b9865f276cbbf152ecf0401c4c7bfdf6dee6f 35ed68a651f4cf8740597433b0f1c3b345841868022e0904e9f342840ba0e502
-R 0f33bb5fad7c4c628b306f509d5f962d
-T +closed 35ed68a651f4cf8740597433b0f1c3b345841868022e0904e9f342840ba0e502
-U drh
-Z 604b4a7ce2ba7e5019d946836f03e6f7
+P ffeec62cb5223ae70bc1889df4c0b241f5d17b1a10156362ca59953028741480
+R 4ed90086329d6a5308b322479c4793a3
+U dan
+Z 58f694df3aeffd18f733f631c7499dc0
diff --git a/manifest.uuid b/manifest.uuid
index 4856962972..6aae45bde9 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-ffeec62cb5223ae70bc1889df4c0b241f5d17b1a10156362ca59953028741480
\ No newline at end of file
+57070c68bbe15fc1d19a765182432e844c082909bdbc63b58fd86b96e2c521dd
\ No newline at end of file
diff --git a/src/window.c b/src/window.c
index ccd19024fe..1d37d4b024 100644
--- a/src/window.c
+++ b/src/window.c
@@ -787,8 +787,20 @@ static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
 
     case TK_AGG_FUNCTION:
     case TK_COLUMN: {
-      Expr *pDup = sqlite3ExprDup(pParse->db, pExpr, 0);
-      p->pSub = sqlite3ExprListAppend(pParse, p->pSub, pDup);
+      int iCol = -1;
+      if( p->pSub ){
+        int i;
+        for(i=0; i<p->pSub->nExpr; i++){
+          if( 0==sqlite3ExprCompare(0, p->pSub->a[i].pExpr, pExpr, -1) ){
+            iCol = i;
+            break;
+          }
+        }
+      }
+      if( iCol<0 ){
+        Expr *pDup = sqlite3ExprDup(pParse->db, pExpr, 0);
+        p->pSub = sqlite3ExprListAppend(pParse, p->pSub, pDup);
+      }
       if( p->pSub ){
         assert( ExprHasProperty(pExpr, EP_Static)==0 );
         ExprSetProperty(pExpr, EP_Static);
@@ -797,7 +809,7 @@ static int selectWindowRewriteExprCb(Walker *pWalker, Expr *pExpr){
         memset(pExpr, 0, sizeof(Expr));
 
         pExpr->op = TK_COLUMN;
-        pExpr->iColumn = p->pSub->nExpr-1;
+        pExpr->iColumn = (iCol<0 ? p->pSub->nExpr-1: iCol);
         pExpr->iTable = p->pWin->iEphCsr;
         pExpr->y.pTab = p->pTab;
       }
diff --git a/test/window1.test b/test/window1.test
index 98a4ce4569..2d748f460c 100644
--- a/test/window1.test
+++ b/test/window1.test
@@ -1256,4 +1256,20 @@ do_execsql_test 33.2 {
   ORDER BY 1;
 } {6 1}
 
+reset_db
+do_execsql_test 34.1 {
+  CREATE TABLE t1(a,b,c);
+}
+do_execsql_test 34.2 {
+  SELECT avg(a) OVER (
+      ORDER BY (SELECT sum(b) OVER ()
+        FROM t1 ORDER BY (
+          SELECT total(d) OVER (ORDER BY c)
+          FROM (SELECT 1 AS d) ORDER BY 1
+          )
+        )
+      )
+  FROM t1;
+}
+
 finish_test