Change the sqlite3BtreeKeySize() interface into sqlite3BtreeIntegerKey() and

make it only work for table btrees.  Change sqlite3BtreeDataSize() into
sqlite3BtreePayloadSize() and make it work for all btrees.  Combine
sqlite3BtreeDataFetch() and sqlite3BtreeKeyFetch() into a single
sqlite3BtreePayloadFetch() routine.  These changes seem to make the
b-tree interface more rational and they reduce both binary size and
CPU usage.

FossilOrigin-Name: bef35e18dd19732f7859287b097feeb593e5900f

8 files changed, 42 insertions, 107 deletions

diff --git a/src/btree.c b/src/btree.c
index 7a2b80c23..4003352a5 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -609,20 +609,17 @@ static void btreeReleaseAllCursorPages(BtCursor *pCur){
 ** the key.
 */
 static int saveCursorKey(BtCursor *pCur){
-  int rc;
+  int rc = SQLITE_OK;
   assert( CURSOR_VALID==pCur->eState );
   assert( 0==pCur->pKey );
   assert( cursorHoldsMutex(pCur) );
 
-  rc = sqlite3BtreeKeySize(pCur, &pCur->nKey);
-  assert( rc==SQLITE_OK );  /* KeySize() cannot fail */
-
-  /* If this is an intKey table, then the above call to BtreeKeySize()
-  ** stores the integer key in pCur->nKey. In this case this value is
-  ** all that is required. Otherwise, if pCur is not open on an intKey
-  ** table, then malloc space for and store the pCur->nKey bytes of key 
-  ** data.  */
-  if( 0==pCur->curIntKey ){
+  if( pCur->curIntKey ){
+    /* Only the rowid is required for a table btree */
+    pCur->nKey = sqlite3BtreeIntegerKey(pCur);
+  }else{
+    /* For an index btree, save the complete key content */
+    pCur->nKey = sqlite3BtreePayloadSize(pCur);
     void *pKey = sqlite3Malloc( pCur->nKey );
     if( pKey ){
       rc = sqlite3BtreeKey(pCur, 0, (int)pCur->nKey, pKey);
@@ -4262,46 +4259,33 @@ int sqlite3BtreeCursorIsValid(BtCursor *pCur){
 #endif /* NDEBUG */
 
 /*
-** Set *pSize to the size of the buffer needed to hold the value of
-** the key for the current entry.  If the cursor is not pointing
-** to a valid entry, *pSize is set to 0. 
-**
-** For a table with the INTKEY flag set, this routine returns the key
-** itself, not the number of bytes in the key.
-**
-** The caller must position the cursor prior to invoking this routine.
-** 
-** This routine cannot fail.  It always returns SQLITE_OK.  
+** Return the value of the integer key or "rowid" for a table btree.
+** This routine is only valid for a cursor that is pointing into a
+** ordinary table btree.  If the cursor points to an index btree or
+** is invalid, the result of this routine is undefined.
 */
-int sqlite3BtreeKeySize(BtCursor *pCur, i64 *pSize){
+i64 sqlite3BtreeIntegerKey(BtCursor *pCur){
   assert( cursorHoldsMutex(pCur) );
   assert( pCur->eState==CURSOR_VALID );
+  assert( pCur->curIntKey );
   getCellInfo(pCur);
-  *pSize = pCur->info.nKey;
-  return SQLITE_OK;
+  return pCur->info.nKey;
 }
 
 /*
-** Set *pSize to the number of bytes of data in the entry the
-** cursor currently points to.
+** Return the number of bytes of payload for the entry that pCur is
+** currently pointing to.  For table btrees, this will be the amount
+** of data.  For index btrees, this will be the size of the key.
 **
 ** The caller must guarantee that the cursor is pointing to a non-NULL
 ** valid entry.  In other words, the calling procedure must guarantee
 ** that the cursor has Cursor.eState==CURSOR_VALID.
-**
-** Failure is not possible.  This function always returns SQLITE_OK.
-** It might just as well be a procedure (returning void) but we continue
-** to return an integer result code for historical reasons.
 */
-int sqlite3BtreeDataSize(BtCursor *pCur, u32 *pSize){
-  assert( cursorOwnsBtShared(pCur) );
+u32 sqlite3BtreePayloadSize(BtCursor *pCur){
+  assert( cursorHoldsMutex(pCur) );
   assert( pCur->eState==CURSOR_VALID );
-  assert( pCur->iPage>=0 );
-  assert( pCur->iPage<BTCURSOR_MAX_DEPTH );
-  assert( pCur->apPage[pCur->iPage]->intKeyLeaf==1 );
   getCellInfo(pCur);
-  *pSize = pCur->info.nPayload;
-  return SQLITE_OK;
+  return pCur->info.nPayload;
 }
 
 /*
@@ -4743,10 +4727,7 @@ static const void *fetchPayload(
 ** These routines is used to get quick access to key and data
 ** in the common case where no overflow pages are used.
 */
-const void *sqlite3BtreeKeyFetch(BtCursor *pCur, u32 *pAmt){
-  return fetchPayload(pCur, pAmt);
-}
-const void *sqlite3BtreeDataFetch(BtCursor *pCur, u32 *pAmt){
+const void *sqlite3BtreePayloadFetch(BtCursor *pCur, u32 *pAmt){
   return fetchPayload(pCur, pAmt);
 }
 
diff --git a/src/btree.h b/src/btree.h
index 5ac119c40..5720df90f 100644
--- a/src/btree.h
+++ b/src/btree.h
@@ -284,11 +284,10 @@ int sqlite3BtreeLast(BtCursor*, int *pRes);
 int sqlite3BtreeNext(BtCursor*, int *pRes);
 int sqlite3BtreeEof(BtCursor*);
 int sqlite3BtreePrevious(BtCursor*, int *pRes);
-int sqlite3BtreeKeySize(BtCursor*, i64 *pSize);
+i64 sqlite3BtreeIntegerKey(BtCursor*);
 int sqlite3BtreeKey(BtCursor*, u32 offset, u32 amt, void*);
-const void *sqlite3BtreeKeyFetch(BtCursor*, u32 *pAmt);
-const void *sqlite3BtreeDataFetch(BtCursor*, u32 *pAmt);
-int sqlite3BtreeDataSize(BtCursor*, u32 *pSize);
+const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt);
+u32 sqlite3BtreePayloadSize(BtCursor*);
 int sqlite3BtreeData(BtCursor*, u32 offset, u32 amt, void*);
 
 char *sqlite3BtreeIntegrityCheck(Btree*, int *aRoot, int nRoot, int, int*);
diff --git a/src/test3.c b/src/test3.c
index 1e4baf757..bfd7c30b6 100644
--- a/src/test3.c
+++ b/src/test3.c
@@ -385,8 +385,7 @@ static int btree_payload_size(
   const char **argv      /* Text of each argument */
 ){
   BtCursor *pCur;
-  int n2;
-  u64 n1;
+  u32 n;
   char zBuf[50];
 
   if( argc!=2 ){
@@ -396,17 +395,9 @@ static int btree_payload_size(
   }
   pCur = sqlite3TestTextToPtr(argv[1]);
   sqlite3BtreeEnter(pCur->pBtree);
-
-  /* The cursor may be in "require-seek" state. If this is the case, the
-  ** call to BtreeDataSize() will fix it. */
-  sqlite3BtreeDataSize(pCur, (u32*)&n2);
-  if( pCur->apPage[pCur->iPage]->intKey ){
-    n1 = 0;
-  }else{
-    sqlite3BtreeKeySize(pCur, (i64*)&n1);
-  }
+  n = sqlite3BtreePayloadSize(pCur);
   sqlite3BtreeLeave(pCur->pBtree);
-  sqlite3_snprintf(sizeof(zBuf),zBuf, "%d", (int)(n1+n2));
+  sqlite3_snprintf(sizeof(zBuf),zBuf, "%u", n);
   Tcl_AppendResult(interp, zBuf, 0);
   return SQLITE_OK;
 }
diff --git a/src/vdbe.c b/src/vdbe.c
index d4392a89d..356cf52f0 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -2380,7 +2380,6 @@ case OP_NotNull: {            /* same as TK_NOTNULL, jump, in1 */
 ** skipped for length() and all content loading can be skipped for typeof().
 */
 case OP_Column: {
-  i64 payloadSize64; /* Number of bytes in the record */
   int p2;            /* column number to retrieve */
   VdbeCursor *pC;    /* The VDBE cursor */
   BtCursor *pCrsr;   /* The BTree cursor */
@@ -2433,22 +2432,9 @@ case OP_Column: {
     }else{
       assert( pC->eCurType==CURTYPE_BTREE );
       assert( pCrsr );
-      if( pC->isTable==0 ){
-        assert( sqlite3BtreeCursorIsValid(pCrsr) );
-        VVA_ONLY(rc =) sqlite3BtreeKeySize(pCrsr, &payloadSize64);
-        assert( rc==SQLITE_OK ); /* True because of CursorMoveto() call above */
-        /* sqlite3BtreeParseCellPtr() uses getVarint32() to extract the
-        ** payload size, so it is impossible for payloadSize64 to be
-        ** larger than 32 bits. */
-        assert( (payloadSize64 & SQLITE_MAX_U32)==(u64)payloadSize64 );
-        pC->aRow = sqlite3BtreeKeyFetch(pCrsr, &avail);
-        pC->payloadSize = (u32)payloadSize64;
-      }else{
-        assert( sqlite3BtreeCursorIsValid(pCrsr) );
-        VVA_ONLY(rc =) sqlite3BtreeDataSize(pCrsr, &pC->payloadSize);
-        assert( rc==SQLITE_OK );   /* DataSize() cannot fail */
-        pC->aRow = sqlite3BtreeDataFetch(pCrsr, &avail);
-      }
+      assert( sqlite3BtreeCursorIsValid(pCrsr) );
+      pC->payloadSize = sqlite3BtreePayloadSize(pCrsr);
+      pC->aRow = sqlite3BtreePayloadFetch(pCrsr, &avail);
       assert( avail<=65536 );  /* Maximum page size is 64KiB */
       if( pC->payloadSize <= (u32)avail ){
         pC->szRow = pC->payloadSize;
@@ -4201,8 +4187,7 @@ case OP_NewRowid: {           /* out2 */
         v = 1;   /* IMP: R-61914-48074 */
       }else{
         assert( sqlite3BtreeCursorIsValid(pC->uc.pCursor) );
-        rc = sqlite3BtreeKeySize(pC->uc.pCursor, &v);
-        assert( rc==SQLITE_OK );   /* Cannot fail following BtreeLast() */
+        v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
         if( v>=MAX_ROWID ){
           pC->useRandomRowid = 1;
         }else{
@@ -4459,8 +4444,7 @@ case OP_Delete: {
     /* If p5 is zero, the seek operation that positioned the cursor prior to
     ** OP_Delete will have also set the pC->movetoTarget field to the rowid of
     ** the row that is being deleted */
-    i64 iKey = 0;
-    sqlite3BtreeKeySize(pC->uc.pCursor, &iKey);
+    i64 iKey = sqlite3BtreeIntegerKey(pC->uc.pCursor);
     assert( pC->movetoTarget==iKey );
   }
 #endif
@@ -4476,7 +4460,7 @@ case OP_Delete: {
     zDb = db->aDb[pC->iDb].zName;
     pTab = pOp->p4.pTab;
     if( (pOp->p5 & OPFLAG_SAVEPOSITION)!=0 && pC->isTable ){
-      sqlite3BtreeKeySize(pC->uc.pCursor, &pC->movetoTarget);
+      pC->movetoTarget = sqlite3BtreeIntegerKey(pC->uc.pCursor);
     }
   }else{
     zDb = 0;   /* Not needed.  Silence a compiler warning. */
@@ -4630,7 +4614,6 @@ case OP_RowData: {
   VdbeCursor *pC;
   BtCursor *pCrsr;
   u32 n;
-  i64 n64;
 
   pOut = &aMem[pOp->p2];
   memAboutToChange(p, pOut);
@@ -4662,20 +4645,9 @@ case OP_RowData: {
   if( rc!=SQLITE_OK ) goto abort_due_to_error;
 #endif
 
-  if( pC->isTable==0 ){
-    assert( !pC->isTable );
-    VVA_ONLY(rc =) sqlite3BtreeKeySize(pCrsr, &n64);
-    assert( rc==SQLITE_OK );    /* True because of CursorMoveto() call above */
-    if( n64>db->aLimit[SQLITE_LIMIT_LENGTH] ){
-      goto too_big;
-    }
-    n = (u32)n64;
-  }else{
-    VVA_ONLY(rc =) sqlite3BtreeDataSize(pCrsr, &n);
-    assert( rc==SQLITE_OK );    /* DataSize() cannot fail */
-    if( n>(u32)db->aLimit[SQLITE_LIMIT_LENGTH] ){
-      goto too_big;
-    }
+  n = sqlite3BtreePayloadSize(pCrsr);
+  if( n>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    goto too_big;
   }
   testcase( n==0 );
   if( sqlite3VdbeMemClearAndResize(pOut, MAX(n,32)) ){
@@ -4740,8 +4712,7 @@ case OP_Rowid: {                 /* out2 */
       pOut->flags = MEM_Null;
       break;
     }
-    rc = sqlite3BtreeKeySize(pC->uc.pCursor, &v);
-    assert( rc==SQLITE_OK );  /* Always so because of CursorRestore() above */
+    v = sqlite3BtreeIntegerKey(pC->uc.pCursor);
   }
   pOut->u.i = v;
   break;
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index 1feecb3e1..83718eae3 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -1650,8 +1650,7 @@ int sqlite3_preupdate_old(sqlite3 *db, int iIdx, sqlite3_value **ppValue){
     u32 nRec;
     u8 *aRec;
 
-    rc = sqlite3BtreeDataSize(p->pCsr->uc.pCursor, &nRec);
-    if( rc!=SQLITE_OK ) goto preupdate_old_out;
+    nRec = sqlite3BtreePayloadSize(p->pCsr->uc.pCursor);
     aRec = sqlite3DbMallocRaw(db, nRec);
     if( !aRec ) goto preupdate_old_out;
     rc = sqlite3BtreeData(p->pCsr->uc.pCursor, 0, nRec, aRec);
diff --git a/src/vdbeaux.c b/src/vdbeaux.c
index bce676f10..63609d72d 100644
--- a/src/vdbeaux.c
+++ b/src/vdbeaux.c
@@ -4315,8 +4315,7 @@ int sqlite3VdbeIdxRowid(sqlite3 *db, BtCursor *pCur, i64 *rowid){
   ** this code can safely assume that nCellKey is 32-bits  
   */
   assert( sqlite3BtreeCursorIsValid(pCur) );
-  VVA_ONLY(rc =) sqlite3BtreeKeySize(pCur, &nCellKey);
-  assert( rc==SQLITE_OK );     /* pCur is always valid so KeySize cannot fail */
+  nCellKey = sqlite3BtreePayloadSize(pCur);
   assert( (nCellKey & SQLITE_MAX_U32)==(u64)nCellKey );
 
   /* Read in the complete content of the index entry */
@@ -4393,8 +4392,7 @@ int sqlite3VdbeIdxKeyCompare(
   assert( pC->eCurType==CURTYPE_BTREE );
   pCur = pC->uc.pCursor;
   assert( sqlite3BtreeCursorIsValid(pCur) );
-  VVA_ONLY(rc =) sqlite3BtreeKeySize(pCur, &nCellKey);
-  assert( rc==SQLITE_OK );    /* pCur is always valid so KeySize cannot fail */
+  nCellKey = sqlite3BtreePayloadSize(pCur);
   /* nCellKey will always be between 0 and 0xffffffff because of the way
   ** that btreeParseCellPtr() and sqlite3GetVarint32() are implemented */
   if( nCellKey<=0 || nCellKey>0x7fffffff ){
diff --git a/src/vdbeblob.c b/src/vdbeblob.c
index f2b3ffef2..01827f94d 100644
--- a/src/vdbeblob.c
+++ b/src/vdbeblob.c
@@ -415,7 +415,7 @@ static int blobReadWrite(
       ** anyhow.
       */
       sqlite3_int64 iKey;
-      sqlite3BtreeKeySize(p->pCsr, &iKey);
+      iKey = sqlite3BtreeIntegerKey(p->pCsr);
       sqlite3VdbePreUpdateHook(
           v, v->apCsr[0], SQLITE_DELETE, p->zDb, p->pTab, iKey, -1
       );
diff --git a/src/vdbemem.c b/src/vdbemem.c
index f9396e570..04cb9c5c6 100644
--- a/src/vdbemem.c
+++ b/src/vdbemem.c
@@ -991,11 +991,7 @@ int sqlite3VdbeMemFromBtree(
   /* Note: the calls to BtreeKeyFetch() and DataFetch() below assert() 
   ** that both the BtShared and database handle mutexes are held. */
   assert( (pMem->flags & MEM_RowSet)==0 );
-  if( key ){
-    zData = (char *)sqlite3BtreeKeyFetch(pCur, &available);
-  }else{
-    zData = (char *)sqlite3BtreeDataFetch(pCur, &available);
-  }
+  zData = (char *)sqlite3BtreePayloadFetch(pCur, &available);
   assert( zData!=0 );
 
   if( offset+amt<=available ){