Index: src/sqliteInt.h
==================================================================
--- src/sqliteInt.h
+++ src/sqliteInt.h
@@ -1391,10 +1391,11 @@
   u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
   u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
   u8 mTrace;                    /* zero or more SQLITE_TRACE flags */
   u8 noSharedCache;             /* True if no shared-cache backends */
   u8 nSqlExec;                  /* Number of pending OP_SqlExec opcodes */
+  LogEst iSortCost;             /* Extra cost applied to sorting */
   int nextPagesize;             /* Pagesize after VACUUM if >0 */
   u32 magic;                    /* Magic number for detect library misuse */
   int nChange;                  /* Value returned by sqlite3_changes() */
   int nTotalChange;             /* Value returned by sqlite3_total_changes() */
   int aLimit[SQLITE_N_LIMIT];   /* Limits */
@@ -1559,11 +1560,11 @@
 ** Bits of the sqlite3.dbOptFlags field that are used by the
 ** sqlite3_test_control(SQLITE_TESTCTRL_OPTIMIZATIONS,...) interface to
 ** selectively disable various optimizations.
 */
 #define SQLITE_QueryFlattener 0x0001   /* Query flattening */
-                          /*  0x0002   available for reuse */
+#define SQLITE_PropagateConst 0x0002   /* The constant propagation opt */
 #define SQLITE_GroupByOrder   0x0004   /* GROUPBY cover of ORDERBY */
 #define SQLITE_FactorOutConst 0x0008   /* Constant factoring */
 #define SQLITE_DistinctOpt    0x0010   /* DISTINCT using indexes */
 #define SQLITE_CoverIdxScan   0x0020   /* Covering index scans */
 #define SQLITE_OrderByIdxJoin 0x0040   /* ORDER BY of joins via index */
@@ -1574,11 +1575,11 @@
 #define SQLITE_Stat34         0x0800   /* Use STAT3 or STAT4 data */
    /* TH3 expects the Stat34  ^^^^^^ value to be 0x0800.  Don't change it */
 #define SQLITE_PushDown       0x1000   /* The push-down optimization */
 #define SQLITE_SimplifyJoin   0x2000   /* Convert LEFT JOIN to JOIN */
 #define SQLITE_SkipScan       0x4000   /* Skip-scans */
-#define SQLITE_PropagateConst 0x8000   /* The constant propagation opt */
+#define SQLITE_SortIfFaster   0x8000   /* ORDER BY using sorter if faster */
 #define SQLITE_AllOpts        0xffff   /* All optimizations */
 
 /*
 ** Macros for testing whether or not optimizations are enabled or disabled.
 */

Index: src/where.c
==================================================================
--- src/where.c
+++ src/where.c
@@ -4107,15 +4107,17 @@
           if( aSortCost[isOrdered]==0 ){
             aSortCost[isOrdered] = whereSortingCost(
                 pWInfo, nRowEst, nOrderBy, isOrdered
             );
           }
-          /* TUNING:  Add a small extra penalty (5) to sorting as an
-          ** extra encouragment to the query planner to select a plan
-          ** where the rows emerge in the correct order without any sorting
-          ** required. */
-          rCost = sqlite3LogEstAdd(rUnsorted, aSortCost[isOrdered]) + 5;
+          rCost = sqlite3LogEstAdd(rUnsorted, aSortCost[isOrdered]);
+          if( OptimizationDisabled(db, SQLITE_SortIfFaster) ){
+            /* if the SortIfFaster optimization is disabled, then set the
+            ** sort cost very high, to encourage the query to return the
+            ** results in natural order, if at all possible */
+            rCost += 200;
+          }
 
           WHERETRACE(0x002,
               ("---- sort cost=%-3d (%d/%d) increases cost %3d to %-3d\n",
                aSortCost[isOrdered], (nOrderBy-isOrdered), nOrderBy, 
                rUnsorted, rCost));

Index: test/where.test
==================================================================
--- test/where.test
+++ test/where.test
@@ -580,11 +580,11 @@
 } {/1 100 4 2 99 9 3 98 16 .* nosort/}
 do_test where-6.7.2 {
   cksort {
     SELECT * FROM t3 WHERE b>0 ORDER BY a LIMIT 1
   }
-} {1 100 4 nosort}
+} {1 100 4 sort}
 ifcapable subquery {
   do_test where-6.8a {
     cksort {
       SELECT * FROM t3 WHERE a IN (3,5,7,1,9,4,2) ORDER BY a LIMIT 3
     }