Add the optimization to avoid some unnecessary calls to sqlite3VdbeRecordUnpack() added to the trunk by [707ea170b3].

FossilOrigin-Name: fc4d04e6b039ea5aeb47739e38c5926e63a4b01b

manifest

@@ -1,5 +1,5 @@
-C Merge\slatest\schanges\sfrom\sorderby-planning\sbranch.
-D 2014-03-28T19:18:16.969
+C Add\sthe\soptimization\sto\savoid\ssome\sunnecessary\scalls\sto\ssqlite3VdbeRecordUnpack()\sadded\sto\sthe\strunk\sby\s[707ea170b3].
+D 2014-03-29T06:27:35.162
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in ad0921c4b2780d01868cf69b419a4f102308d125
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -286,7 +286,7 @@ F src/vdbeapi.c 0ed6053f947edd0b30f64ce5aeb811872a3450a4
 F src/vdbeaux.c 1153175fb57a8454e1c8cf79b59b7bf92b26779d
 F src/vdbeblob.c 15377abfb59251bccedd5a9c7d014a895f0c04aa
 F src/vdbemem.c 6fc77594c60f6155404f3f8d71bf36d1fdeb4447
-F src/vdbesort.c 01068b89364fa2bffeba9b929367ed04661e97f7
+F src/vdbesort.c d7ef3c431d7996907815a13579952506bf2bdf8b
 F src/vdbetrace.c 6f52bc0c51e144b7efdcfb2a8f771167a8816767
 F src/vtab.c 21b932841e51ebd7d075e2d0ad1415dce8d2d5fd
 F src/wal.c 76e7fc6de229bea8b30bb2539110f03a494dc3a8
@@ -1160,7 +1160,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh d1a6de74685f360ab718efda6265994b99bbea01
 F tool/win/sqlite.vsix 030f3eeaf2cb811a3692ab9c14d021a75ce41fff
-P 8cb2b02baa7ef9aa96319e977f0315328f944237 3047a25f1c41e83f0b4772f7c36fbfec0f12dc7e
-R 132477cf9a18d083088d044c20454723
+P 4c7fb5423430f3b936befaa7c309f8e1968ee7d8
+R c555f8c440b397229a1b1d80867cea18
 U dan
-Z b189ca5a1e8d41a36f80415af9011f68
+Z 5b7820939497d4f0728d4d29380b4189

manifest.uuid

@@ -1 +1 @@
-4c7fb5423430f3b936befaa7c309f8e1968ee7d8
+fc4d04e6b039ea5aeb47739e38c5926e63a4b01b

src/vdbesort.c

@@ -1052,11 +1052,59 @@ static int vdbeSorterNext(
   rc = vdbeSorterIterNext(&pMerger->aIter[iPrev]);
 
   /* Update contents of aTree[] */
-  for(i=(pMerger->nTree+iPrev)/2; rc==SQLITE_OK && i>0; i=i/2){
-    rc = vdbeSorterDoCompare(pThread, pMerger, i);
+  if( rc==SQLITE_OK ){
+    int i;                      /* Index of aTree[] to recalculate */
+    VdbeSorterIter *pIter1;     /* First iterator to compare */
+    VdbeSorterIter *pIter2;     /* Second iterator to compare */
+    u8 *pKey2;                  /* To pIter2->aKey, or 0 if record cached */
+
+    /* Find the first two iterators to compare. The one that was just
+    ** advanced (iPrev) and the one next to it in the array.  */
+    pIter1 = &pMerger->aIter[(iPrev & 0xFFFE)];
+    pIter2 = &pMerger->aIter[(iPrev | 0x0001)];
+    pKey2 = pIter2->aKey;
+
+    for(i=(pMerger->nTree+iPrev)/2; i>0; i=i/2){
+      /* Compare pIter1 and pIter2. Store the result in variable iRes. */
+      int iRes;
+      if( pIter1->pFile==0 ){
+        iRes = +1;
+      }else if( pIter2->pFile==0 ){
+        iRes = -1;
+      }else{
+        vdbeSorterCompare(pThread, 0,
+            pIter1->aKey, pIter1->nKey, pKey2, pIter2->nKey, &iRes
+        );
+      }
+
+      /* If pIter1 contained the smaller value, set aTree[i] to its index.
+      ** Then set pIter2 to the next iterator to compare to pIter1. In this
+      ** case there is no cache of pIter2 in pThread->pUnpacked, so set
+      ** pKey2 to point to the record belonging to pIter2.
+      **
+      ** Alternatively, if pIter2 contains the smaller of the two values,
+      ** set aTree[i] to its index and update pIter1. If vdbeSorterCompare()
+      ** was actually called above, then pThread->pUnpacked now contains
+      ** a value equivalent to pIter2. So set pKey2 to NULL to prevent
+      ** vdbeSorterCompare() from decoding pIter2 again.
+      **
+      ** If the two values were equal, then the value from the oldest
+      ** PMA should be considered smaller. The VdbeSorter.aIter[] array
+      ** is sorted from oldest to newest, so pIter1 contains older values
+      ** than pIter2 iff (pIter1<pIter2).  */
+      if( iRes<0 || (iRes==0 && pIter1<pIter2) ){
+        pMerger->aTree[i] = (int)(pIter1 - pMerger->aIter);
+        pIter2 = &pMerger->aIter[ pMerger->aTree[i ^ 0x0001] ];
+        pKey2 = pIter2->aKey;
+      }else{
+        if( pIter1->pFile ) pKey2 = 0;
+        pMerger->aTree[i] = (int)(pIter2 - pMerger->aIter);
+        pIter1 = &pMerger->aIter[ pMerger->aTree[i ^ 0x0001] ];
+      }
+    }
+    *pbEof = (pMerger->aIter[pMerger->aTree[1]].pFile==0);
   }
 
-  *pbEof = (pMerger->aIter[pMerger->aTree[1]].pFile==0);
   return rc;
 }