Simplify the CellInfo structure for a size reduction and performance

improvement.

FossilOrigin-Name: bf59df66b3613c38cfb13a68091b8328ebb22c78

manifest

@@ -1,5 +1,5 @@
-C Add\sthe\s"multiplex_truncate"\sPRAGMA\sto\sthe\smultiplexor\sextension,\sfor\nquerying\sand\ssetting\sthe\struncate\sflag\son\sa\sdatabase\sconnection.
+C Simplify\sthe\sCellInfo\sstructure\sfor\sa\ssize\sreduction\sand\sperformance\nimprovement.
-D 2014-09-23T18:30:00.961
+D 2014-09-23T21:25:19.710
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in cf57f673d77606ab0f2d9627ca52a9ba1464146a
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -172,9 +172,9 @@ F src/auth.c d8abcde53426275dab6243b441256fcd8ccbebb2
 F src/backup.c a31809c65623cc41849b94d368917f8bb66e6a7e
 F src/bitvec.c 19a4ba637bd85f8f63fc8c9bae5ade9fb05ec1cb
 F src/btmutex.c 49ca66250c7dfa844a4d4cb8272b87420d27d3a5
-F src/btree.c c2645014c525c0b4a8327971c331f55b8747b443
+F src/btree.c 2a7c67d474624732612f97a89e34cf85f8cd4905
 F src/btree.h a79aa6a71e7f1055f01052b7f821bd1c2dce95c8
-F src/btreeInt.h e0ecb5dba292722039a7540beb3fc448103273cc
+F src/btreeInt.h a5a869ec2c3e56ee9e214ee748d7942716be0340
 F src/build.c 8dbca25988045fbf2a33c9631c42706fa6449e60
 F src/callback.c 7b44ce59674338ad48b0e84e7b72f935ea4f68b0
 F src/complete.c 535183afb3c75628b78ce82612931ac7cdf26f14
@@ -1200,7 +1200,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P ae9a42b268ad3f7d21a5813bb931e795c6917014
+P d2962a5f388f30a02429e0c8b87399f482b5604c
-R 38a39c43ba2ffbcd445b1883953d7c57
+R 3633e95932853227476c5d6e8f02e193
 U drh
-Z 9797dd2e522d2cafa5364dec0ef721e8
+Z 6131f39965fefa27be7e69636d8311d7

manifest.uuid

@@ -1 +1 @@
-d2962a5f388f30a02429e0c8b87399f482b5604c
+bf59df66b3613c38cfb13a68091b8328ebb22c78

src/btree.c

@@ -977,38 +977,33 @@ static void btreeParseCellPtr(
   u8 *pCell,              /* Pointer to the cell text. */
   CellInfo *pInfo         /* Fill in this structure */
 ){
-  u16 n;                  /* Number bytes in cell content header */
+  u8 *pIter = &pCell[pPage->childPtrSize];
   u32 nPayload;           /* Number of bytes of cell payload */
 
   assert( sqlite3_mutex_held(pPage->pBt->mutex) );
-
-  pInfo->pCell = pCell;
   assert( pPage->leaf==0 || pPage->leaf==1 );
-  n = pPage->childPtrSize;
-  assert( n==4-4*pPage->leaf );
   if( pPage->intKey ){
     if( pPage->hasData ){
-      assert( n==0 );
+      assert( pIter==pCell );
-      n = getVarint32(pCell, nPayload);
+      pIter += getVarint32(pIter, nPayload);
     }else{
       nPayload = 0;
     }
-    n += getVarint(&pCell[n], (u64*)&pInfo->nKey);
+    pIter += getVarint(pIter, (u64*)&pInfo->nKey);
-    pInfo->nData = nPayload;
   }else{
-    pInfo->nData = 0;
+    pIter += getVarint32(pIter, nPayload);
-    n += getVarint32(&pCell[n], nPayload);
     pInfo->nKey = nPayload;
   }
   pInfo->nPayload = nPayload;
-  pInfo->nHeader = n;
+  pInfo->pPayload = pIter;
   testcase( nPayload==pPage->maxLocal );
   testcase( nPayload==pPage->maxLocal+1 );
-  if( likely(nPayload<=pPage->maxLocal) ){
+  if( nPayload<=pPage->maxLocal ){
     /* This is the (easy) common case where the entire payload fits
     ** on the local page.  No overflow is required.
     */
-    if( (pInfo->nSize = (u16)(n+nPayload))<4 ) pInfo->nSize = 4;
+    pInfo->nSize = nPayload + (u16)(pIter - pCell);
+    if( pInfo->nSize<4 ) pInfo->nSize = 4;
     pInfo->nLocal = (u16)nPayload;
     pInfo->iOverflow = 0;
   }else{
@@ -1035,7 +1030,7 @@ static void btreeParseCellPtr(
     }else{
       pInfo->nLocal = (u16)minLocal;
     }
-    pInfo->iOverflow = (u16)(pInfo->nLocal + n);
+    pInfo->iOverflow = (u16)(&pInfo->pPayload[pInfo->nLocal] - pCell);
     pInfo->nSize = pInfo->iOverflow + 4;
   }
 }
@@ -1132,7 +1127,6 @@ static void ptrmapPutOvflPtr(MemPage *pPage, u8 *pCell, int *pRC){
   if( *pRC ) return;
   assert( pCell!=0 );
   btreeParseCellPtr(pPage, pCell, &info);
-  assert( (info.nData+(pPage->intKey?0:info.nKey))==info.nPayload );
   if( info.iOverflow ){
     Pgno ovfl = get4byte(&pCell[info.iOverflow]);
     ptrmapPut(pPage->pBt, ovfl, PTRMAP_OVERFLOW1, pPage->pgno, pRC);
@@ -3866,8 +3860,9 @@ int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
 int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
   assert( cursorHoldsMutex(pCur) );
   assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->apPage[pCur->iPage]->intKey==1 );
   getCellInfo(pCur);
-  *pSize = pCur->info.nData;
+  *pSize = pCur->info.nPayload;
   return SQLITE_OK;
 }
 
@@ -4018,7 +4013,6 @@ static int accessPayload(
 ){
   unsigned char *aPayload;
   int rc = SQLITE_OK;
-  u32 nKey;
   int iIdx = 0;
   MemPage *pPage = pCur->apPage[pCur->iPage]; /* Btree page of current entry */
   BtShared *pBt = pCur->pBt;                  /* Btree this cursor belongs to */
@@ -4033,15 +4027,13 @@ static int accessPayload(
   assert( eOp!=2 || offset==0 );      /* Always start from beginning for eOp==2 */
 
   getCellInfo(pCur);
-  aPayload = pCur->info.pCell + pCur->info.nHeader;
+  aPayload = pCur->info.pPayload;
-  nKey = (pPage->intKey ? 0 : (int)pCur->info.nKey);
 #ifdef SQLITE_DIRECT_OVERFLOW_READ
-  bEnd = (offset+amt==nKey+pCur->info.nData);
+  bEnd = offset+amt==pCur->info.nPayload;
 #endif
+  assert( offset+amt <= pCur->info.nPayload );
 
-  if( NEVER(offset+amt > nKey+pCur->info.nData) 
+  if( &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize] ){
-   || &aPayload[pCur->info.nLocal] > &pPage->aData[pBt->usableSize]
-  ){
     /* Trying to read or write past the end of the data is an error */
     return SQLITE_CORRUPT_BKPT;
   }
@@ -4275,7 +4267,7 @@ static const void *fetchPayload(
   assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
   assert( pCur->info.nSize>0 );
   *pAmt = pCur->info.nLocal;
-  return (void*)(pCur->info.pCell + pCur->info.nHeader);
+  return (void*)pCur->info.pPayload;
 }
 
 
@@ -5640,9 +5632,10 @@ static int fillInCell(
   }
   nHeader += putVarint(&pCell[nHeader], *(u64*)&nKey);
   btreeParseCellPtr(pPage, pCell, &info);
-  assert( info.nHeader==nHeader );
+  assert( nHeader=(int)(info.pPayload - pCell) );
   assert( info.nKey==nKey );
-  assert( info.nData==(u32)(nData+nZero) );
+  assert( pPage->intKey==0 || info.nPayload==(u32)(nData+nZero) );
+  assert( pPage->intKey==1 || info.nPayload==nKey );
   
   /* Fill in the payload */
   nPayload = nData + nZero;
@@ -8086,19 +8079,18 @@ static int checkTreePage(
              "On tree page %d cell %d: ", iPage, i);
     pCell = findCell(pPage,i);
     btreeParseCellPtr(pPage, pCell, &info);
-    sz = info.nData;
+    sz = info.nPayload;
-    if( !pPage->intKey ) sz += (int)info.nKey;
     /* For intKey pages, check that the keys are in order.
     */
-    else if( i==0 ) nMinKey = nMaxKey = info.nKey;
+    if( pPage->intKey ){
-    else{
+      if( i==0 ){
-      if( info.nKey <= nMaxKey ){
+        nMinKey = nMaxKey = info.nKey;
+      }else if( info.nKey <= nMaxKey ){
         checkAppendMsg(pCheck, zContext, 
-            "Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
+           "Rowid %lld out of order (previous was %lld)", info.nKey, nMaxKey);
       }
       nMaxKey = info.nKey;
     }
-    assert( sz==info.nPayload );
     if( (sz>info.nLocal) 
      && (&pCell[info.iOverflow]<=&pPage->aData[pBt->usableSize])
     ){

src/btreeInt.h

@@ -456,12 +456,10 @@ struct BtShared {
 */
 typedef struct CellInfo CellInfo;
 struct CellInfo {
-  i64 nKey;      /* The key for INTKEY tables, or number of bytes in key */
+  i64 nKey;      /* The key for INTKEY tables, or nPayload otherwise */
-  u8 *pCell;     /* Pointer to the start of cell content */
+  u8 *pPayload;  /* Pointer to the start of payload */
-  u32 nData;     /* Number of bytes of data */
+  u32 nPayload;  /* Bytes of payload */
-  u32 nPayload;  /* Total amount of payload */
+  u16 nLocal;    /* Amount of payload held locally, not on overflow */
-  u16 nHeader;   /* Size of the cell content header in bytes */
-  u16 nLocal;    /* Amount of payload held locally */
   u16 iOverflow; /* Offset to overflow page number.  Zero if no overflow */
   u16 nSize;     /* Size of the cell content on the main b-tree page */
 };