From: drh <drh@noemail.net>
Date: Thu, 19 May 2016 22:40:04 +0000 (+0000)
Subject: Appears to work now.  Needs test cases, more comments, and code optimization.
X-Git-Tag: version-3.14.0~157^2~2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d711e522292566c8ef055da3af8f095dabea6781;p=thirdparty%2Fsqlite.git

Appears to work now.  Needs test cases, more comments, and code optimization.

FossilOrigin-Name: 990fe50c9182f74c9b54a12602c4c30d891273e6
---

diff --git a/manifest b/manifest
index d01cdd7db8..39cec630ce 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C In\sa\squery\swith\sboth\sORDER\sBY\sand\sLIMIT,\sif\sthe\sinner\sloop\ssatisfies\sthe\s\nORDER\sBY\sthen\stry\sto\scut\sshort\seach\sinvocation\sof\sthe\sinner\sloop\sonce\sthe\nLIMIT\shas\sbeen\ssatisfied.\s\sThis\scheck-in\sis\sa\spartial\simplementation\sonly.
-D 2016-05-19T22:13:37.318
+C Appears\sto\swork\snow.\s\sNeeds\stest\scases,\smore\scomments,\sand\scode\soptimization.
+D 2016-05-19T22:40:04.862
 F Makefile.in f59e0763ff448719fc1bd25513882b0567286317
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 306d73e854b1a92ea06e5d1e637faa5c44de53c7
@@ -383,7 +383,7 @@ F src/shell.c 14ff7f660530a52b117d110ba3390b7b2eb719b6
 F src/sqlite.h.in 9984129d86243424b765fcb3f147c697bd20bb54
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 98f72cbfe00169c39089115427d06ea05fe4b4a2
-F src/sqliteInt.h 863cf0d421611ccfa30541ee5ffe761c896ffa5b
+F src/sqliteInt.h 09621b4b7dba808b24262c2480ea75b045001853
 F src/sqliteLimit.h c0373387c287c8d0932510b5547ecde31b5da247
 F src/status.c 70912d7be68e9e2dbc4010c93d344af61d4c59ba
 F src/table.c 5226df15ab9179b9ed558d89575ea0ce37b03fc9
@@ -458,7 +458,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 4db22ed7e77bcf672b1a685d6ddeffba8d5be302
 F src/wal.h 2f7c831cf3b071fa548bf2d5cac640846a7ff19c
 F src/walker.c 0f142b5bd3ed2041fc52d773880748b212e63354
-F src/where.c a7454e62ca13f1ff54892339022f8cb0a8bb3728
+F src/where.c 0e54a03d11d4e99ad25528f42ff4c9a6fa7a23da
 F src/whereInt.h 6e18240be400bef8e4dbafea605251707c5dbf49
 F src/wherecode.c e3f18fcda2d7f8218a09dc33cf495dca0efa6e3e
 F src/whereexpr.c eacc0e60d029a082b4fc0cc42ea98544add1319e
@@ -1489,10 +1489,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 58b516e8c0b00a41bc0364eab267bc2ecb9efeff
-R 766495aa6109f75a3c3b0e829e8d3b47
-T *branch * orderby-limit
-T *sym-orderby-limit *
-T -sym-trunk *
+P 852d1eda6ecca1171f6ed800b06f5b4854672002
+R 664cd7ecddde2637b78c890f65cd5e15
 U drh
-Z 1f191cc43f073ab10b6b672b5a12f950
+Z a9319f97e8df1737542ca3813ad100bc
diff --git a/manifest.uuid b/manifest.uuid
index ec9b410bfa..2ec1166f5a 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-852d1eda6ecca1171f6ed800b06f5b4854672002
\ No newline at end of file
+990fe50c9182f74c9b54a12602c4c30d891273e6
\ No newline at end of file
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 7adfd3779b..b15d788093 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2540,7 +2540,7 @@ struct SrcList {
 #define WHERE_WANT_DISTINCT    0x0100 /* All output needs to be distinct */
 #define WHERE_SORTBYGROUP      0x0200 /* Support sqlite3WhereIsSorted() */
 #define WHERE_SEEK_TABLE       0x0400 /* Do not defer seeks on main table */
-                        /*     0x0800    not currently used */
+#define WHERE_ORDERBY_LIMIT    0x0800 /* ORDERBY+LIMIT on the inner loop */
                         /*     0x1000    not currently used */
                         /*     0x2000    not currently used */
 #define WHERE_USE_LIMIT        0x4000 /* Use the LIMIT in cost estimates */
diff --git a/src/where.c b/src/where.c
index 521d2e19ec..cb008b7df4 100644
--- a/src/where.c
+++ b/src/where.c
@@ -3262,7 +3262,7 @@ static i8 wherePathSatisfiesOrderBy(
   WhereInfo *pWInfo,    /* The WHERE clause */
   ExprList *pOrderBy,   /* ORDER BY or GROUP BY or DISTINCT clause to check */
   WherePath *pPath,     /* The WherePath to check */
-  u16 wctrlFlags,       /* Might contain WHERE_GROUPBY or WHERE_DISTINCTBY */
+  u16 wctrlFlags,       /* WHERE_GROUPBY or _DISTINCTBY or _ORDERBY_LIMIT */
   u16 nLoop,            /* Number of entries in pPath->aLoop[] */
   WhereLoop *pLast,     /* Add this WhereLoop to the end of pPath->aLoop[] */
   Bitmask *pRevMask     /* OUT: Mask of WhereLoops to run in reverse order */
@@ -3273,6 +3273,7 @@ static i8 wherePathSatisfiesOrderBy(
   u8 isOrderDistinct;   /* All prior WhereLoops are order-distinct */
   u8 distinctColumns;   /* True if the loop has UNIQUE NOT NULL columns */
   u8 isMatch;           /* iColumn matches a term of the ORDER BY clause */
+  u16 eqOpMask;         /* Allowed equality operators */
   u16 nKeyCol;          /* Number of key columns in pIndex */
   u16 nColumn;          /* Total number of ordered columns in the index */
   u16 nOrderBy;         /* Number terms in the ORDER BY clause */
@@ -3323,9 +3324,16 @@ static i8 wherePathSatisfiesOrderBy(
   obDone = MASKBIT(nOrderBy)-1;
   orderDistinctMask = 0;
   ready = 0;
+  eqOpMask = WO_EQ | WO_IS | WO_ISNULL;
+  if( wctrlFlags & WHERE_ORDERBY_LIMIT ) eqOpMask |= WO_IN;
   for(iLoop=0; isOrderDistinct && obSat<obDone && iLoop<=nLoop; iLoop++){
     if( iLoop>0 ) ready |= pLoop->maskSelf;
-    pLoop = iLoop<nLoop ? pPath->aLoop[iLoop] : pLast;
+    if( iLoop<nLoop ){
+      pLoop = pPath->aLoop[iLoop];
+      if( wctrlFlags & WHERE_ORDERBY_LIMIT ) continue;
+    }else{
+      pLoop = pLast;
+    }
     if( pLoop->wsFlags & WHERE_VIRTUALTABLE ){
       if( pLoop->u.vtab.isOrdered ) obSat = obDone;
       break;
@@ -3343,7 +3351,7 @@ static i8 wherePathSatisfiesOrderBy(
       if( pOBExpr->op!=TK_COLUMN ) continue;
       if( pOBExpr->iTable!=iCur ) continue;
       pTerm = sqlite3WhereFindTerm(&pWInfo->sWC, iCur, pOBExpr->iColumn,
-                       ~ready, WO_EQ|WO_ISNULL|WO_IS, 0);
+                       ~ready, eqOpMask, 0);
       if( pTerm==0 ) continue;
       if( (pTerm->eOperator&(WO_EQ|WO_IS))!=0 && pOBExpr->iColumn>=0 ){
         const char *z1, *z2;
@@ -3383,10 +3391,12 @@ static i8 wherePathSatisfiesOrderBy(
       for(j=0; j<nColumn; j++){
         u8 bOnce;   /* True to run the ORDER BY search loop */
 
-        /* Skip over == and IS NULL terms */
+        /* Skip over == and IS and ISNULL terms.
+        ** (Also skip IN terms when doing WHERE_ORDERBY_LIMIT processing)
+        */
         if( j<pLoop->u.btree.nEq
          && pLoop->nSkip==0
-         && ((i = pLoop->aLTerm[j]->eOperator) & (WO_EQ|WO_ISNULL|WO_IS))!=0
+         && ((i = pLoop->aLTerm[j]->eOperator) & eqOpMask)!=0
         ){
           if( i & WO_ISNULL ){
             testcase( isOrderDistinct );
@@ -3913,6 +3923,15 @@ static int wherePathSolver(WhereInfo *pWInfo, LogEst nRowEst){
       pWInfo->revMask = pFrom->revLoop;
       if( pWInfo->nOBSat<=0 ){
         pWInfo->nOBSat = 0;
+        if( nLoop>0 ){
+          Bitmask m;
+          int rc = wherePathSatisfiesOrderBy(pWInfo, pWInfo->pOrderBy, pFrom,
+                      WHERE_ORDERBY_LIMIT, nLoop-1, pFrom->aLoop[nLoop-1], &m);
+          if( rc==pWInfo->pOrderBy->nExpr ){
+            pWInfo->bOrderedInnerLoop = 1;
+            pWInfo->revMask = m;
+          }
+        }
       }
     }
     if( (pWInfo->wctrlFlags & WHERE_SORTBYGROUP)