diff --git a/manifest b/manifest
index 282bd77..7b95455 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Minor\sadjustments\sto\sindentation\sand\sspacing\sfor\sclarity.\s\sNo\schanges\sto\scode.
-D 2017-09-11T18:37:44.991
+C Refactor\snames\sof\sconstants\sand\sfunctions\sassociated\swith\sthe\sauxiliary\noperators\sfor\sxBestIndex.
+D 2017-09-11T19:47:37.315
 F Makefile.in c644bbe8ebe4aae82ad6783eae6b6beea4c727b99ff97568b847ced5e2ac7afb
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 6a7a74bf60ad395098c0bd175ab054cd65ef85d7f034198d52bcc4d9e5fb4c6b
@@ -539,10 +539,10 @@
 F src/wal.c 839db09792fead5052bb35e533fa485e134913d547d05b5f42e537b73e63f07a
 F src/wal.h 8de5d2d3de0956d6f6cb48c83a4012d5f227b8fe940f3a349a4b7e85ebcb492a
 F src/walker.c 3ccfa8637f95355bff61144e01a615b8ef26f79c312880848da73f03367da1e6
-F src/where.c 3db249dfcef40357a295bc481af99cfcadc896d4eef259992681534db909e335
-F src/whereInt.h 93bb90b77d39901eda31b44d8e90da1351193ccfe96876f89b58a93a33b84c3d
+F src/where.c d97f97ca6017747b7361af7f168a640d667c41cd1d4e91c2c5b2bd7538815d07
+F src/whereInt.h 82c04c5075308abbac59180c8bad5ecb45b07453981f60a53f3c7dee21e1e971
 F src/wherecode.c e8c2ece5843ea56e6c90277d421f2d628f3f7b7c976642369cc519f008e1d2b1
-F src/whereexpr.c ffc3c90f68ad28c6eca1c8b05029f361bc151187be578985d992788d31f295ae
+F src/whereexpr.c 4953ca4e769c047d0a00a1ba9085849626b1f3a6e89f6befcf5c38fa0722acdd
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test a6d901b436328bd67a79b41bb0ac2663918fe3bd
 F test/affinity3.test 6a101af2fc945ce2912f6fe54dd646018551710d
@@ -1653,7 +1653,7 @@
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8d24e0803d180448e637e33030a4ebf2c20eb1cab1074290c08f2eee0a23f66c
-R 0a1fb7fe2a3156d2459600f96873dd1d
+P d3153abda6fd48015b007081734738b9cc4622e3564dc78a7a470a72dc2ca236
+R 6bf300e1c6f9b6f8c5e667046a0485fa
 U drh
-Z 68e910dc75889ef64693d78040f26d24
+Z 6c35ef01413cc8966446242df55841d2
diff --git a/manifest.uuid b/manifest.uuid
index 239259e..638546b 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d3153abda6fd48015b007081734738b9cc4622e3564dc78a7a470a72dc2ca236
\ No newline at end of file
+0fb992af669e765760a94d2b6e2330b21a98f39f18445a94b0a2290560368d58
\ No newline at end of file
diff --git a/src/where.c b/src/where.c
index a396b7d..7b806a7 100644
--- a/src/where.c
+++ b/src/where.c
@@ -931,7 +931,7 @@
     pIdxCons[j].iTermOffset = i;
     op = pTerm->eOperator & WO_ALL;
     if( op==WO_IN ) op = WO_EQ;
-    if( op==WO_MATCH ){
+    if( op==WO_AUX ){
       pIdxCons[j].op = pTerm->eMatchOp;
     }else if( op & (WO_ISNULL|WO_IS) ){
       if( op==WO_ISNULL ){
@@ -949,8 +949,7 @@
       assert( WO_LE==SQLITE_INDEX_CONSTRAINT_LE );
       assert( WO_GT==SQLITE_INDEX_CONSTRAINT_GT );
       assert( WO_GE==SQLITE_INDEX_CONSTRAINT_GE );
-      assert( WO_MATCH==SQLITE_INDEX_CONSTRAINT_MATCH );
-      assert( pTerm->eOperator&(WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_MATCH) );
+      assert( pTerm->eOperator&(WO_IN|WO_EQ|WO_LT|WO_LE|WO_GT|WO_GE|WO_AUX) );
 
       if( op & (WO_LT|WO_LE|WO_GT|WO_GE)
        && sqlite3ExprIsVector(pTerm->pExpr->pRight) 
diff --git a/src/whereInt.h b/src/whereInt.h
index bac81da..0aa7bc1 100644
--- a/src/whereInt.h
+++ b/src/whereInt.h
@@ -515,7 +515,6 @@
 **     WO_LE    == SQLITE_INDEX_CONSTRAINT_LE
 **     WO_GT    == SQLITE_INDEX_CONSTRAINT_GT
 **     WO_GE    == SQLITE_INDEX_CONSTRAINT_GE
-**     WO_MATCH == SQLITE_INDEX_CONSTRAINT_MATCH
 */
 #define WO_IN     0x0001
 #define WO_EQ     0x0002
@@ -523,7 +522,7 @@
 #define WO_LE     (WO_EQ<<(TK_LE-TK_EQ))
 #define WO_GT     (WO_EQ<<(TK_GT-TK_EQ))
 #define WO_GE     (WO_EQ<<(TK_GE-TK_EQ))
-#define WO_MATCH  0x0040
+#define WO_AUX    0x0040       /* Op useful to virtual tables only */
 #define WO_IS     0x0080
 #define WO_ISNULL 0x0100
 #define WO_OR     0x0200       /* Two or more OR-connected terms */
diff --git a/src/whereexpr.c b/src/whereexpr.c
index 45d3a7e..da07f56 100644
--- a/src/whereexpr.c
+++ b/src/whereexpr.c
@@ -312,27 +312,32 @@
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
 /*
-** Check to see if the given expression is of the form
+** Check to see if the pExpr expression is a form that needs to be passed
+** to the xBestIndex method of virtual tables.  Forms of interest include:
 **
-**         column OP expr
+**          Expression                   Virtual Table Operator
+**          -----------------------      ---------------------------------
+**      1.  column MATCH expr            SQLITE_INDEX_CONSTRAINT_MATCH
+**      2.  column GLOB expr             SQLITE_INDEX_CONSTRAINT_GLOB
+**      3.  column LIKE expr             SQLITE_INDEX_CONSTRAINT_LIKE
+**      4.  column REGEXP expr           SQLITE_INDEX_CONSTRAINT_REGEXP
+**      5.  column != expr               SQLITE_INDEX_CONSTRAINT_NE
+**      6.  expr != column               SQLITE_INDEX_CONSTRAINT_NE
+**      7.  column IS NOT expr           SQLITE_INDEX_CONSTRAINT_ISNOT
+**      8.  expr IS NOT column           SQLITE_INDEX_CONSTRAINT_ISNOT
+**      9.  column IS NOT NULL           SQLITE_INDEX_CONSTRAINT_ISNOTNULL
 **
-** where OP is one of MATCH, GLOB, LIKE or REGEXP and "column" is a 
-** column of a virtual table. If so, set *ppLeft to point to the
-** expression for "column", *ppRight to "expr" and return 1.
-**
-** Also check if the expression is one of:
-**
-**         column != expr
-**         column IS NOT expr
-**         column IS NOT NULL
-**
-** where "column" is a column of a virtual table. If so, set *ppLeft
-** to point to "column", *ppRight to "expr" and return 1. Or, if "expr"
-** is also a column of a virtual table, return 2.
+** In every case, "column" must be a column of a virtual table.  If there
+** is a match, set *ppLeft to the "column" expression, set *ppRight to the 
+** "expr" expression (even though in forms (6) and (8) the column is on the
+** right and the expression is on the left).  Also set *peOp2 to the
+** appropriate virtual table operator.  The return value is 1 or 2 if there
+** is a match.  The usual return is 1, but if the RHS is also a column
+** of virtual table in forms (5) or (7) then return 2.
 **
 ** If the expression matches none of the patterns above, return 0.
 */
-static int isMatchOfColumn(
+static int isAuxiliaryVtabOperator(
   Expr *pExpr,                    /* Test this expression */
   unsigned char *peOp2,           /* OUT: 0 for MATCH, or else an op2 value */
   Expr **ppLeft,                  /* Column expression to left of MATCH/op2 */
@@ -352,9 +357,6 @@
     Expr *pCol;                     /* Column reference */
     int i;
 
-    if( pExpr->op!=TK_FUNCTION ){
-      return 0;
-    }
     pList = pExpr->x.pList;
     if( pList==0 || pList->nExpr!=2 ){
       return 0;
@@ -638,7 +640,7 @@
           for(j=0, pAndTerm=pAndWC->a; j<pAndWC->nTerm; j++, pAndTerm++){
             assert( pAndTerm->pExpr );
             if( allowedOp(pAndTerm->pExpr->op) 
-             || pAndTerm->eOperator==WO_MATCH 
+             || pAndTerm->eOperator==WO_AUX
             ){
               b |= sqlite3WhereGetMask(&pWInfo->sMaskSet, pAndTerm->leftCursor);
             }
@@ -1220,17 +1222,19 @@
 #endif /* SQLITE_OMIT_LIKE_OPTIMIZATION */
 
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-  /* Add a WO_MATCH auxiliary term to the constraint set if the
-  ** current expression is of the form:  column MATCH expr.
+  /* Add a WO_AUX auxiliary term to the constraint set if the
+  ** current expression is of the form "column OP expr" where OP
+  ** is an operator that gets passed into virtual tables but which is
+  ** not normally optimized for ordinary tables.  In other words, OP
+  ** is one of MATCH, LIKE, GLOB, REGEXP, !=, IS, IS NOT, or NOT NULL.
   ** This information is used by the xBestIndex methods of
   ** virtual tables.  The native query optimizer does not attempt
   ** to do anything with MATCH functions.
   */
   if( pWC->op==TK_AND ){
     Expr *pRight, *pLeft;
-    int i;
-    int res = isMatchOfColumn(pExpr, &eOp2, &pLeft, &pRight);
-    for(i=0; i<res; i++){
+    int res = isAuxiliaryVtabOperator(pExpr, &eOp2, &pLeft, &pRight);
+    while( res-- > 0 ){
       int idxNew;
       WhereTerm *pNewTerm;
       Bitmask prereqColumn, prereqExpr;
@@ -1250,7 +1254,7 @@
         pNewTerm->prereqRight = prereqExpr;
         pNewTerm->leftCursor = pLeft->iTable;
         pNewTerm->u.leftColumn = pLeft->iColumn;
-        pNewTerm->eOperator = WO_MATCH;
+        pNewTerm->eOperator = WO_AUX;
         pNewTerm->eMatchOp = eOp2;
         markTermAsChild(pWC, idxNew, idxTerm);
         pTerm = &pWC->a[idxTerm];