Code simplifications in select.c and where.c.

FossilOrigin-Name: 4f20ac90bce8bd7ba43ef59af5cc4ef7aa282fe8

manifest

@@ -1,5 +1,5 @@
-C Minor\scleanup\sof\sthe\ssqlite3Select()\sprocedure.
+C Code\ssimplifications\sin\sselect.c\sand\swhere.c.
-D 2015-06-06T00:18:01.663
+D 2015-06-06T18:30:17.822
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 994bab32a3a69e0c35bd148b65cde49879772964
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -250,7 +250,7 @@ F src/printf.c 13ce37e5574f9b0682fa86dbcf9faf76b9d82a15
 F src/random.c ba2679f80ec82c4190062d756f22d0c358180696
 F src/resolve.c 84c571794e3ee5806274d95158a4c0177c6c4708
 F src/rowset.c eccf6af6d620aaa4579bd3b72c1b6395d9e9fa1e
-F src/select.c 630623e6536115ec360e07be3cb5e01fab9166f9
+F src/select.c d507fe715b12e6aba157fa34b0a5680809e59bac
 F src/shell.c 07dda7cd692911d2f22269953418d049f2e2c0ee
 F src/sqlite.h.in d165beeceb6b40af60f352a4d4e37e02d9af7df0
 F src/sqlite3.rc 992c9f5fb8285ae285d6be28240a7e8d3a7f2bad
@@ -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 5cc416ad6d8b6d2027735fcf7c5a6165bb745636
 F src/whereInt.h a6f5a762bc1b4b1c76e1cea79976b437ac35a435
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test a6d901b436328bd67a79b41bb0ac2663918fe3bd
@@ -1282,7 +1282,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P be8e3fc70e4c13b28b07985df3457960f58ffddd
+P f4c90d06bb941453d8110680c7b279e471e8f034
-R c9ba4b66998c994d5a4d88f3868eca18
+R 042f84cf941d82ab55744b287e51eff7
 U drh
-Z f5a7ad6c64c16a42ea0d51c96b63ee57
+Z f6bc4d318934fdab6d55b7066c6ff342

manifest.uuid

@@ -1 +1 @@
-f4c90d06bb941453d8110680c7b279e471e8f034
+4f20ac90bce8bd7ba43ef59af5cc4ef7aa282fe8

src/select.c

@@ -1310,28 +1310,27 @@ static void generateSortTail(
 */
 #ifdef SQLITE_ENABLE_COLUMN_METADATA
 # define columnType(A,B,C,D,E,F) columnTypeImpl(A,B,C,D,E,F)
+#else /* if !defined(SQLITE_ENABLE_COLUMN_METADATA) */
+# define columnType(A,B,C,D,E,F) columnTypeImpl(A,B,F)
+#endif
 static const char *columnTypeImpl(
   NameContext *pNC, 
   Expr *pExpr,
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
   const char **pzOrigDb,
   const char **pzOrigTab,
   const char **pzOrigCol,
+#endif
   u8 *pEstWidth
 ){
-  char const *zOrigDb = 0;
-  char const *zOrigTab = 0;
-  char const *zOrigCol = 0;
-#else /* if !defined(SQLITE_ENABLE_COLUMN_METADATA) */
-# define columnType(A,B,C,D,E,F) columnTypeImpl(A,B,F)
-static const char *columnTypeImpl(
-  NameContext *pNC, 
-  Expr *pExpr,
-  u8 *pEstWidth
-){
-#endif /* !defined(SQLITE_ENABLE_COLUMN_METADATA) */
   char const *zType = 0;
   int j;
   u8 estWidth = 1;
+#ifdef SQLITE_ENABLE_COLUMN_METADATA
+  char const *zOrigDb = 0;
+  char const *zOrigTab = 0;
+  char const *zOrigCol = 0;
+#endif
 
   if( NEVER(pExpr==0) || pNC->pSrcList==0 ) return 0;
   switch( pExpr->op ){

src/where.c

@@ -616,6 +616,11 @@ static void exprAnalyze(SrcList*, WhereClause*, int);
 
 /*
 ** Call exprAnalyze on all terms in a WHERE clause.  
+**
+** Note that exprAnalyze() might add new virtual terms onto the
+** end of the WHERE clause.  We do not want to analyze these new
+** virtual terms, so start analyzing at the end and work forward
+** so that the added virtual terms are never processed.
 */
 static void exprAnalyzeAll(
   SrcList *pTabList,       /* the FROM clause */
@@ -891,7 +896,7 @@ static void whereCombineDisjuncts(
 **
 ** CASE 2:
 **
-** If there are exactly two disjuncts one side has x>A and the other side
+** If there are exactly two disjuncts and one side has x>A and the other side
 ** has x=A (for the same x and A) then add a new virtual conjunct term to the
 ** WHERE clause of the form "x>=A".  Example:
 **
@@ -920,22 +925,22 @@ static void whereCombineDisjuncts(
 ** is decided elsewhere.  This analysis only looks at whether subterms
 ** appropriate for indexing exist.
 **
-** All examples A through E above satisfy case 2.  But if a term
+** All examples A through E above satisfy case 3.  But if a term
 ** also satisfies case 1 (such as B) we know that the optimizer will
-** always prefer case 1, so in that case we pretend that case 2 is not
+** always prefer case 1, so in that case we pretend that case 3 is not
 ** satisfied.
 **
 ** It might be the case that multiple tables are indexable.  For example,
 ** (E) above is indexable on tables P, Q, and R.
 **
-** Terms that satisfy case 2 are candidates for lookup by using
+** Terms that satisfy case 3 are candidates for lookup by using
 ** separate indices to find rowids for each subterm and composing
 ** the union of all rowids using a RowSet object.  This is similar
 ** to "bitmap indices" in other database engines.
 **
 ** OTHERWISE:
 **
-** If neither case 1 nor case 2 apply, then leave the eOperator set to
+** If none of cases 1, 2, or 3 apply, then leave the eOperator set to
 ** zero.  This term is not useful for search.
 */
 static void exprAnalyzeOrTerm(
@@ -973,7 +978,7 @@ static void exprAnalyzeOrTerm(
   assert( pOrWc->nTerm>=2 );
 
   /*
-  ** Compute the set of tables that might satisfy cases 1 or 2.
+  ** Compute the set of tables that might satisfy cases 1 or 3.
   */
   indexable = ~(Bitmask)0;
   chngToIN = ~(Bitmask)0;
@@ -1188,7 +1193,7 @@ static void exprAnalyzeOrTerm(
 ** relation:
 **   1.  The SQLITE_Transitive optimization must be enabled
 **   2.  Must be either an == or an IS operator
-**   3.  Not originating the ON clause of an OUTER JOIN
+**   3.  Not originating in the ON clause of an OUTER JOIN
 **   4.  The affinities of A and B must be compatible
 **   5a. Both operands use the same collating sequence OR
 **   5b. The overall collating sequence is BINARY
@@ -1589,8 +1594,8 @@ static int findIndexCol(
 ** Return true if the DISTINCT expression-list passed as the third argument
 ** is redundant.
 **
-** A DISTINCT list is redundant if the database contains some subset of
+** A DISTINCT list is redundant if any subset of the columns in the
-** columns that are unique and non-null.
+** DISTINCT list are collectively unique and individually non-null.
 */
 static int isDistinctRedundant(
   Parse *pParse,            /* Parsing context */
@@ -6689,15 +6694,9 @@ WhereInfo *sqlite3WhereBegin(
   }
 #endif
 
-  /* Analyze all of the subexpressions.  Note that exprAnalyze() might
+  /* Analyze all of the subexpressions. */
-  ** add new virtual terms onto the end of the WHERE clause.  We do not
-  ** want to analyze these virtual terms, so start analyzing at the end
-  ** and work forward so that the added virtual terms are never processed.
-  */
   exprAnalyzeAll(pTabList, &pWInfo->sWC);
-  if( db->mallocFailed ){
+  if( db->mallocFailed ) goto whereBeginError;
-    goto whereBeginError;
-  }
 
   if( wctrlFlags & WHERE_WANT_DISTINCT ){
     if( isDistinctRedundant(pParse, pTabList, &pWInfo->sWC, pResultSet) ){
@@ -6713,8 +6712,7 @@ WhereInfo *sqlite3WhereBegin(
   /* Construct the WhereLoop objects */
   WHERETRACE(0xffff,("*** Optimizer Start ***\n"));
 #if defined(WHERETRACE_ENABLED)
-  /* Display all terms of the WHERE clause */
+  if( sqlite3WhereTrace & 0x100 ){ /* Display all terms of the WHERE clause */
-  if( sqlite3WhereTrace & 0x100 ){
     int i;
     for(i=0; i<sWLB.pWC->nTerm; i++){
       whereTermPrint(&sWLB.pWC->a[i], i);
@@ -6726,12 +6724,11 @@ WhereInfo *sqlite3WhereBegin(
     rc = whereLoopAddAll(&sWLB);
     if( rc ) goto whereBeginError;
   
-    /* Display all of the WhereLoop objects if wheretrace is enabled */
+#ifdef WHERETRACE_ENABLED
-#ifdef WHERETRACE_ENABLED /* !=0 */
+    if( sqlite3WhereTrace ){    /* Display all of the WhereLoop objects */
-    if( sqlite3WhereTrace ){
       WhereLoop *p;
       int i;
-      static char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
+      static const char zLabel[] = "0123456789abcdefghijklmnopqrstuvwyxz"
                                              "ABCDEFGHIJKLMNOPQRSTUVWYXZ";
       for(p=pWInfo->pLoops, i=0; p; p=p->pNextLoop, i++){
         p->cId = zLabel[i%sizeof(zLabel)];
@@ -6753,7 +6750,7 @@ WhereInfo *sqlite3WhereBegin(
   if( pParse->nErr || NEVER(db->mallocFailed) ){
     goto whereBeginError;
   }
-#ifdef WHERETRACE_ENABLED /* !=0 */
+#ifdef WHERETRACE_ENABLED
   if( sqlite3WhereTrace ){
     sqlite3DebugPrintf("---- Solution nRow=%d", pWInfo->nRowOut);
     if( pWInfo->nOBSat>0 ){
@@ -6816,7 +6813,7 @@ WhereInfo *sqlite3WhereBegin(
   /* If the caller is an UPDATE or DELETE statement that is requesting
   ** to use a one-pass algorithm, determine if this is appropriate.
   ** The one-pass algorithm only works if the WHERE clause constrains
-  ** the statement to update a single row.
+  ** the statement to update or delete a single row.
   */
   assert( (wctrlFlags & WHERE_ONEPASS_DESIRED)==0 || pWInfo->nLevel==1 );
   if( (wctrlFlags & WHERE_ONEPASS_DESIRED)!=0 
@@ -6830,7 +6827,6 @@ WhereInfo *sqlite3WhereBegin(
   /* Open all tables in the pTabList and any indices selected for
   ** searching those tables.
   */
-  notReady = ~(Bitmask)0;
   for(ii=0, pLevel=pWInfo->a; ii<nTabList; ii++, pLevel++){
     Table *pTab;     /* Table to open */
     int iDb;         /* Index of database containing table/index */
@@ -6919,7 +6915,6 @@ WhereInfo *sqlite3WhereBegin(
       }
     }
     if( iDb>=0 ) sqlite3CodeVerifySchema(pParse, iDb);
-    notReady &= ~getMask(&pWInfo->sMaskSet, pTabItem->iCursor);
   }
   pWInfo->iTop = sqlite3VdbeCurrentAddr(v);
   if( db->mallocFailed ) goto whereBeginError;