Add a new opcode to the VDBE that gives the b-tree a hint about the set

of columns in a table or index that are actually used by the query.

FossilOrigin-Name: f167bba446b78dd7538d0b2bae3e6678f3b1ba28

manifest

@@ -1,5 +1,5 @@
-C Change\sthe\sname\sof\sSrcList.a[].zIndex\sto\sthe\smore\sdescriptive\nSrcList.a[0].zIndexedBy.
-D 2015-06-04T12:08:53.261
+C Add\sa\snew\sopcode\sto\sthe\sVDBE\sthat\sgives\sthe\sb-tree\sa\shint\sabout\sthe\sset\nof\scolumns\sin\sa\stable\sor\sindex\sthat\sare\sactually\sused\sby\sthe\squery.
+D 2015-06-05T15:59:57.203
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 994bab32a3a69e0c35bd148b65cde49879772964
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -202,7 +202,7 @@ F src/ctime.c 5a0b735dc95604766f5dac73973658eef782ee8b
 F src/date.c e4d50b3283696836ec1036b695ead9a19e37a5ac
 F src/dbstat.c f402e77e25089c6003d0c60b3233b9b3947d599a
 F src/delete.c 37964e6c1d73ff49cbea9ff690c9605fb15f600e
-F src/expr.c d953b9f03c3c0f701f87a418fcfb9cba8befc6e0
+F src/expr.c 1980fffc7505d7696b5ec53475ed4bd6fd39f490
 F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
 F src/fkey.c c9b63a217d86582c22121699a47f22f524608869
 F src/func.c 5b8b8e77a0fb644eaf8947d413804622e32692b6
@@ -312,11 +312,11 @@ F src/update.c 487747b328b7216bb7f6af0695d6937d5c9e605f
 F src/utf.c fc6b889ba0779b7722634cdeaa25f1930d93820c
 F src/util.c a6431c92803b975b7322724a7b433e538d243539
 F src/vacuum.c 2ddd5cad2a7b9cef7f9e431b8c7771634c6b1701
-F src/vdbe.c 0a6a1df5c31415a0e974e74e7bd412616889453d
-F src/vdbe.h 7e538ecf47dccb307ea2d087c3ddc2dd8d70e79d
-F src/vdbeInt.h f0ccddac48583d5f762dc554a9f79e85ea8807e0
+F src/vdbe.c c9b8985dfc5df9bd512342ea2e56af4be30cb31a
+F src/vdbe.h 90048aea1910f9df93e6044592bd4a466dc9c5e7
+F src/vdbeInt.h 20295e482121d13437f69985f77db211cdc8bac1
 F src/vdbeapi.c 6a0d7757987018ff6b1b81bc5293219cd26bb299
-F src/vdbeaux.c 46f9bc4b32866082eb87a36b461e487a0bbdbe8e
+F src/vdbeaux.c 89c85926ce346988d275132e05ddb0c9681807c2
 F src/vdbeblob.c 4f2e8e075d238392df98c5e03a64342465b03f90
 F src/vdbemem.c 67b302dc6df64b4d6785881c5d22bd4f9b17739d
 F src/vdbesort.c f5009e7a35e3065635d8918b9a31f498a499976b
@@ -326,7 +326,7 @@ F src/vxworks.h c18586c8edc1bddbc15c004fa16aeb1e1342b4fb
 F src/wal.c ce2cb2d06faab54d1bce3e739bec79e063dd9113
 F src/wal.h df01efe09c5cb8c8e391ff1715cca294f89668a4
 F src/walker.c c253b95b4ee44b21c406e2a1052636c31ea27804
-F src/where.c 2db8137f14644e2117c2e2350e08a05e02d6bdab
+F src/where.c f957a39866d126cfe45bc20737085a01d241dab2
 F src/whereInt.h a6f5a762bc1b4b1c76e1cea79976b437ac35a435
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test a6d901b436328bd67a79b41bb0ac2663918fe3bd
@@ -1282,7 +1282,10 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 9f035c45a4b84203e67b6e1b23cf11691dc43f1e
-R ad5ce5f5b8d17995393297d9ed2a0d0e
+P 6a9cf063379118dbb95c6cdc6d60af50e9867177
+R 26fb3dd084da8ca4266e7b6ea31232cf
+T *branch * column-usage-hint
+T *sym-column-usage-hint *
+T -sym-trunk *
 U drh
-Z de80e81db21512cdc452bca7645bb7ca
+Z 4c54f566ac1c4e0f96dff99143c1643e

manifest.uuid

@@ -1 +1 @@
-6a9cf063379118dbb95c6cdc6d60af50e9867177
+f167bba446b78dd7538d0b2bae3e6678f3b1ba28

src/expr.c

@@ -2208,17 +2208,6 @@ static void sqlite3ExprCodeIN(
 }
 #endif /* SQLITE_OMIT_SUBQUERY */
 
-/*
-** Duplicate an 8-byte value
-*/
-static char *dup8bytes(Vdbe *v, const char *in){
-  char *out = sqlite3DbMallocRaw(sqlite3VdbeDb(v), 8);
-  if( out ){
-    memcpy(out, in, 8);
-  }
-  return out;
-}
-
 #ifndef SQLITE_OMIT_FLOATING_POINT
 /*
 ** Generate an instruction that will put the floating point
@@ -2231,12 +2220,10 @@ static char *dup8bytes(Vdbe *v, const char *in){
 static void codeReal(Vdbe *v, const char *z, int negateFlag, int iMem){
   if( ALWAYS(z!=0) ){
     double value;
-    char *zV;
     sqlite3AtoF(z, &value, sqlite3Strlen30(z), SQLITE_UTF8);
     assert( !sqlite3IsNaN(value) ); /* The new AtoF never returns NaN */
     if( negateFlag ) value = -value;
-    zV = dup8bytes(v, (char*)&value);
-    sqlite3VdbeAddOp4(v, OP_Real, 0, iMem, 0, zV, P4_REAL);
+    sqlite3VdbeAddOp4Dup8(v, OP_Real, 0, iMem, 0, (u8*)&value, P4_REAL);
   }
 }
 #endif
@@ -2262,10 +2249,8 @@ static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
     assert( z!=0 );
     c = sqlite3DecOrHexToI64(z, &value);
     if( c==0 || (c==2 && negFlag) ){
-      char *zV;
       if( negFlag ){ value = c==2 ? SMALLEST_INT64 : -value; }
-      zV = dup8bytes(v, (char*)&value);
-      sqlite3VdbeAddOp4(v, OP_Int64, 0, iMem, 0, zV, P4_INT64);
+      sqlite3VdbeAddOp4Dup8(v, OP_Int64, 0, iMem, 0, (u8*)&value, P4_INT64);
     }else{
 #ifdef SQLITE_OMIT_FLOATING_POINT
       sqlite3ErrorMsg(pParse, "oversized integer: %s%s", negFlag ? "-" : "", z);

src/vdbe.c

@@ -3511,6 +3511,26 @@ case OP_Close: {
   break;
 }
 
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+/* Opcode: ColumnsUsed P1 * * P4 *
+**
+** This opcode (which only exists if SQLite was compiled with
+** SQLITE_ENABLE_COLUMN_USED_MASK) identifies which columns of the
+** table or index for cursor P1 are used.  P4 is a 64-bit integer
+** (P4_INT64) in which the first 63 bits are one for each of the
+** first 63 columns of the table or index that are actually used
+** by the cursor.  The high-order bit is set if any column after
+** the 64th is used.
+*/
+case OP_ColumnsUsed: {
+  VdbeCursor *pC;
+  pC = p->apCsr[pOp->p1];
+  assert( pC->pCursor );
+  pC->maskUsed = *(u64*)pOp->p4.pI64;
+  break;
+}
+#endif
+
 /* Opcode: SeekGE P1 P2 P3 P4 *
 ** Synopsis: key=r[P3@P4]
 **

src/vdbe.h

@@ -169,6 +169,7 @@ int sqlite3VdbeAddOp1(Vdbe*,int,int);
 int sqlite3VdbeAddOp2(Vdbe*,int,int,int);
 int sqlite3VdbeAddOp3(Vdbe*,int,int,int,int);
 int sqlite3VdbeAddOp4(Vdbe*,int,int,int,int,const char *zP4,int);
+int sqlite3VdbeAddOp4Dup8(Vdbe*,int,int,int,int,const u8*,int);
 int sqlite3VdbeAddOp4Int(Vdbe*,int,int,int,int,int);
 int sqlite3VdbeAddOpList(Vdbe*, int nOp, VdbeOpList const *aOp, int iLineno);
 void sqlite3VdbeAddParseSchemaOp(Vdbe*,int,char*);

src/vdbeInt.h

@@ -83,6 +83,9 @@ struct VdbeCursor {
   i64 seqCount;         /* Sequence counter */
   i64 movetoTarget;     /* Argument to the deferred sqlite3BtreeMoveto() */
   VdbeSorter *pSorter;  /* Sorter object for OP_SorterOpen cursors */
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+  u64 maskUsed;         /* Mask of columns used by this cursor */
+#endif
 
   /* Cached information about the header for the data record that the
   ** cursor is currently pointing to.  Only valid if cacheStatus matches

src/vdbeaux.c

@@ -233,6 +233,23 @@ int sqlite3VdbeAddOp4(
   return addr;
 }
 
+/*
+** Add an opcode that includes the p4 value with a P4_INT64 type.
+*/
+int sqlite3VdbeAddOp4Dup8(
+  Vdbe *p,            /* Add the opcode to this VM */
+  int op,             /* The new opcode */
+  int p1,             /* The P1 operand */
+  int p2,             /* The P2 operand */
+  int p3,             /* The P3 operand */
+  const u8 *zP4,      /* The P4 operand */
+  int p4type          /* P4 operand type */
+){
+  char *p4copy = sqlite3DbMallocRaw(sqlite3VdbeDb(p), 8);
+  if( p4copy ) memcpy(p4copy, zP4, 8);
+  return sqlite3VdbeAddOp4(p, op, p1, p2, p3, p4copy, p4type);
+}
+
 /*
 ** Add an OP_ParseSchema opcode.  This routine is broken out from
 ** sqlite3VdbeAddOp4() since it needs to also needs to mark all btrees

src/where.c

@@ -6871,6 +6871,10 @@ WhereInfo *sqlite3WhereBegin(
                             SQLITE_INT_TO_PTR(n), P4_INT32);
         assert( n<=pTab->nCol );
       }
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+      sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, pTabItem->iCursor, 0, 0,
+                            (const u8*)&pTabItem->colUsed, P4_INT64);
+#endif
     }else{
       sqlite3TableLock(pParse, iDb, pTab->tnum, 0, pTab->zName);
     }
@@ -6916,6 +6920,21 @@ WhereInfo *sqlite3WhereBegin(
           sqlite3VdbeChangeP5(v, OPFLAG_SEEKEQ); /* Hint to COMDB2 */
         }
         VdbeComment((v, "%s", pIx->zName));
+#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
+        {
+          u64 colUsed = 0;
+          int ii, jj;
+          for(ii=0; ii<pIx->nColumn; ii++){
+            jj = pIx->aiColumn[ii];
+            if( jj<0 ) continue;
+            if( jj>63 ) jj = 63;
+            if( (pTabItem->colUsed & MASKBIT(jj))==0 ) continue;
+            colUsed |= ((u64)1)<<(ii<63 ? ii : 63);
+          }
+          sqlite3VdbeAddOp4Dup8(v, OP_ColumnsUsed, iIndexCur, 0, 0,
+                                (u8*)&colUsed, P4_INT64);
+        }
+#endif /* SQLITE_ENABLE_COLUMN_USED_MASK */
       }
     }
     if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);