Small size reduction and performance improvement in whereScanNext().

FossilOrigin-Name: d861ee17eb900a607de6ec3f4a5d5c24cfb834a0

manifest

@@ -1,5 +1,5 @@
-C If\sall\sbranches\sof\san\sOR\soptimize\sscan\sthat\sis\sthe\srhs\sof\sa\sLEFT\sJOIN\suse\sthe\nsame\sindex,\sset\sthe\sindex\scursor\sto\sreturn\sNULL\svalues\sif\sthere\sare\sno\smatches\nfor\sa\srow\son\sthe\slhs.
-D 2016-10-26T16:05:10.157
+C Small\ssize\sreduction\sand\sperformance\simprovement\sin\swhereScanNext().
+D 2016-10-26T17:57:40.045
 F Makefile.in 6fd48ffcf7c2deea7499062d1f3747f986c19678
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 5151cc64c4c05f3455f4f692ad11410a810d937f
@@ -468,7 +468,7 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c 0b44e89742024d3b6992bf404d2ab692113e1e60
 F src/wal.h bf03a23da3100ab25e5c0363450233cfee09cfc2
 F src/walker.c 91a6df7435827e41cff6bb7df50ea00934ee78b0
-F src/where.c 125af074723cf390d0e71ed1ca385240e6d4ea7c
+F src/where.c 694dd84a7017f2b284e1da55b5bf00bfd3e1f4e4
 F src/whereInt.h 2bcc3d176e6091cb8f50a30b65c006e88a73614d
 F src/wherecode.c 717a65294df46f30e9b9933d2a63a4bcbca5a9a8
 F src/whereexpr.c 379d0017fb7bc9e5a4d8cd4b056c747de946430e
@@ -1528,7 +1528,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 86675ae0abc78960a2faec55d115804acfc3be6d e7b9bc678ecb75c594d9d3ade12a99a8d551cdc9
-R c240eb27502d404e84b4aff903524b82
-U dan
-Z 498360080b36f95cb7f4a5ed51292736
+P ec9dab8054c71d112c68f58a45821b38c2a45677
+R 48fa39390c766bcfb2f028645ad7c897
+U drh
+Z 1bf2b72e2a8cf9aca52b2af50acc10fd

manifest.uuid

@@ -1 +1 @@
-ec9dab8054c71d112c68f58a45821b38c2a45677
+d861ee17eb900a607de6ec3f4a5d5c24cfb834a0

src/where.c

@@ -198,11 +198,14 @@ static WhereTerm *whereScanNext(WhereScan *pScan){
   WhereTerm *pTerm;    /* The term being tested */
   int k = pScan->k;    /* Where to start scanning */
 
-  while( pScan->iEquiv<=pScan->nEquiv ){
-    iCur = pScan->aiCur[pScan->iEquiv-1];
+  assert( pScan->iEquiv<=pScan->nEquiv );
+  pWC = pScan->pWC;
+  while(1){
     iColumn = pScan->aiColumn[pScan->iEquiv-1];
     if( iColumn==XN_EXPR && pScan->pIdxExpr==0 ) return 0;
-    while( (pWC = pScan->pWC)!=0 ){
+    iCur = pScan->aiCur[pScan->iEquiv-1];
+    assert( pWC!=0 );
+    do{
       for(pTerm=pWC->a+k; k<pWC->nTerm; k++, pTerm++){
         if( pTerm->leftCursor==iCur
          && pTerm->u.leftColumn==iColumn
@@ -252,15 +255,17 @@ static WhereTerm *whereScanNext(WhereScan *pScan){
               testcase( pTerm->eOperator & WO_IS );
               continue;
             }
+            pScan->pWC = pWC;
             pScan->k = k+1;
             return pTerm;
           }
         }
       }
-      pScan->pWC = pScan->pWC->pOuter;
+      pWC = pWC->pOuter;
       k = 0;
-    }
-    pScan->pWC = pScan->pOrigWC;
+    }while( pWC!=0 );
+    if( pScan->iEquiv>=pScan->nEquiv ) break;
+    pWC = pScan->pOrigWC;
     k = 0;
     pScan->iEquiv++;
   }