diff --git a/buildheader/db.h_4_1 b/buildheader/db.h_4_1
index e83617161fc..19de1cc9b6c 100644
--- a/buildheader/db.h_4_1
+++ b/buildheader/db.h_4_1
@@ -251,7 +251,8 @@ struct __toku_dbc {
   int (*c_getf_current)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_first)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_last)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
-  void* __toku_dummy0[10];
+  int (*c_getf_heavi)(DBC *, u_int32_t, void(*f)(DBT const *, DBT const *, void *, int), void *extra_f, int (*h)(const DBT *key, const DBT *value, void *extra_h), void *extra_h, int direction);
+  void* __toku_dummy0[9];
   char __toku_dummy1[104];
   int (*c_close) (DBC *); /* 32-bit offset=188 size=4, 64=bit offset=272 size=8 */
   int (*c_count) (DBC *, db_recno_t *, u_int32_t); /* 32-bit offset=192 size=4, 64=bit offset=280 size=8 */
diff --git a/buildheader/db.h_4_3 b/buildheader/db.h_4_3
index 661384971b8..5fb3822264a 100644
--- a/buildheader/db.h_4_3
+++ b/buildheader/db.h_4_3
@@ -267,7 +267,8 @@ struct __toku_dbc {
   int (*c_getf_current)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_first)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_last)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
-  void* __toku_dummy0[8];
+  int (*c_getf_heavi)(DBC *, u_int32_t, void(*f)(DBT const *, DBT const *, void *, int), void *extra_f, int (*h)(const DBT *key, const DBT *value, void *extra_h), void *extra_h, int direction);
+  void* __toku_dummy0[7];
   char __toku_dummy1[112];
   int (*c_close) (DBC *); /* 32-bit offset=188 size=4, 64=bit offset=264 size=8 */
   int (*c_count) (DBC *, db_recno_t *, u_int32_t); /* 32-bit offset=192 size=4, 64=bit offset=272 size=8 */
diff --git a/buildheader/db.h_4_4 b/buildheader/db.h_4_4
index b3d9475337a..42798ed7402 100644
--- a/buildheader/db.h_4_4
+++ b/buildheader/db.h_4_4
@@ -272,7 +272,8 @@ struct __toku_dbc {
   int (*c_getf_current)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_first)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_last)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
-  void* __toku_dummy0[10];
+  int (*c_getf_heavi)(DBC *, u_int32_t, void(*f)(DBT const *, DBT const *, void *, int), void *extra_f, int (*h)(const DBT *key, const DBT *value, void *extra_h), void *extra_h, int direction);
+  void* __toku_dummy0[9];
   char __toku_dummy1[104];
   int (*c_close) (DBC *); /* 32-bit offset=188 size=4, 64=bit offset=272 size=8 */
   int (*c_count) (DBC *, db_recno_t *, u_int32_t); /* 32-bit offset=192 size=4, 64=bit offset=280 size=8 */
diff --git a/buildheader/db.h_4_5 b/buildheader/db.h_4_5
index 9efad2a477b..ae3ebd05fc1 100644
--- a/buildheader/db.h_4_5
+++ b/buildheader/db.h_4_5
@@ -271,7 +271,8 @@ struct __toku_dbc {
   int (*c_getf_current)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_first)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_last)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
-  void* __toku_dummy0[14];
+  int (*c_getf_heavi)(DBC *, u_int32_t, void(*f)(DBT const *, DBT const *, void *, int), void *extra_f, int (*h)(const DBT *key, const DBT *value, void *extra_h), void *extra_h, int direction);
+  void* __toku_dummy0[13];
   char __toku_dummy1[104];
   int (*c_close) (DBC *); /* 32-bit offset=204 size=4, 64=bit offset=304 size=8 */
   int (*c_count) (DBC *, db_recno_t *, u_int32_t); /* 32-bit offset=208 size=4, 64=bit offset=312 size=8 */
diff --git a/buildheader/db.h_4_6 b/buildheader/db.h_4_6
index c656e08ee66..407625c5454 100644
--- a/buildheader/db.h_4_6
+++ b/buildheader/db.h_4_6
@@ -11,9 +11,9 @@ extern "C" {
 #define TOKUDB 1
 #define DB_VERSION_MAJOR 4
 #define DB_VERSION_MINOR 6
-#define DB_VERSION_PATCH 21
+#define DB_VERSION_PATCH 19
 #ifndef _TOKUDB_WRAP_H
-#define DB_VERSION_STRING "Tokutek: TokuDB 4.6.21"
+#define DB_VERSION_STRING "Tokutek: TokuDB 4.6.19"
 #else
 #define DB_VERSION_STRING_ydb "Tokutek: TokuDB (wrapped bdb)"
 #endif
@@ -276,7 +276,8 @@ struct __toku_dbc {
   int (*c_getf_current)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_first)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_last)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
-  void* __toku_dummy0[24];
+  int (*c_getf_heavi)(DBC *, u_int32_t, void(*f)(DBT const *, DBT const *, void *, int), void *extra_f, int (*h)(const DBT *key, const DBT *value, void *extra_h), void *extra_h, int direction);
+  void* __toku_dummy0[23];
   char __toku_dummy1[104];
   int (*c_close) (DBC *); /* 32-bit offset=244 size=4, 64=bit offset=384 size=8 */
   int (*c_count) (DBC *, db_recno_t *, u_int32_t); /* 32-bit offset=248 size=4, 64=bit offset=392 size=8 */
diff --git a/buildheader/make_db_h.c b/buildheader/make_db_h.c
index 1e0750c07de..aebd4c633ea 100644
--- a/buildheader/make_db_h.c
+++ b/buildheader/make_db_h.c
@@ -330,6 +330,9 @@ int main (int argc __attribute__((__unused__)), char *argv[] __attribute__((__un
 			     "int (*c_getf_current)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *)",
 			     "int (*c_getf_first)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *)",
 			     "int (*c_getf_last)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *)",
+                             "int (*c_getf_heavi)(DBC *, u_int32_t, "
+                                 "void(*f)(DBT const *, DBT const *, void *, int), void *extra_f, "
+                                 "int (*h)(const DBT *key, const DBT *value, void *extra_h), void *extra_h, int direction)",
 			     NULL};
 	assert(sizeof(dbc_fields32)==sizeof(dbc_fields64));
 	print_struct("dbc", 1, dbc_fields32, dbc_fields64, sizeof(dbc_fields32)/sizeof(dbc_fields32[0]), extra);
diff --git a/include/db.h b/include/db.h
index b3d9475337a..42798ed7402 100644
--- a/include/db.h
+++ b/include/db.h
@@ -272,7 +272,8 @@ struct __toku_dbc {
   int (*c_getf_current)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_first)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
   int (*c_getf_last)(DBC *, u_int32_t, void(*)(DBT const *, DBT const *, void *), void *);
-  void* __toku_dummy0[10];
+  int (*c_getf_heavi)(DBC *, u_int32_t, void(*f)(DBT const *, DBT const *, void *, int), void *extra_f, int (*h)(const DBT *key, const DBT *value, void *extra_h), void *extra_h, int direction);
+  void* __toku_dummy0[9];
   char __toku_dummy1[104];
   int (*c_close) (DBC *); /* 32-bit offset=188 size=4, 64=bit offset=272 size=8 */
   int (*c_count) (DBC *, db_recno_t *, u_int32_t); /* 32-bit offset=192 size=4, 64=bit offset=280 size=8 */
diff --git a/newbrt/brt.c b/newbrt/brt.c
index b4c45358150..0a9592ef6bf 100644
--- a/newbrt/brt.c
+++ b/newbrt/brt.c
@@ -3322,6 +3322,64 @@ get_next:;
     return -1;
 }
 
+int toku_brt_cursor_peek_prev(BRT_CURSOR cursor, DBT *outkey, DBT *outval) {
+    if (toku_omt_cursor_is_valid(cursor->omtcursor)) {
+	{
+	    int rr = toku_read_and_pin_brt_header(cursor->brt->cf, &cursor->brt->h);
+	    if (rr!=0) return rr;
+	    uint64_t h_counter = cursor->brt->h->root_put_counter;
+	    rr = toku_unpin_brt_header(cursor->brt);
+	    assert(rr==0);
+	    if (h_counter != cursor->root_put_counter) return -1;
+	}
+	OMTVALUE le;
+        u_int32_t index = 0;
+        int r = toku_omt_cursor_current_index(cursor->omtcursor, &index);
+        assert(r==0);
+        OMT omt = toku_omt_cursor_get_omt(cursor->omtcursor);
+get_prev:;
+        if (index>0) {
+            r = toku_omt_fetch(omt, --index, &le, NULL); 
+            if (r==0) {
+                if (le_is_provdel(le)) goto get_prev;
+                toku_fill_dbt(outkey, le_latest_key(le), le_latest_keylen(le));
+                toku_fill_dbt(outval, le_latest_val(le), le_latest_vallen(le));
+                return 0;
+            }
+        }
+    }
+    return -1;
+}
+
+int toku_brt_cursor_peek_next(BRT_CURSOR cursor, DBT *outkey, DBT *outval) {
+    if (toku_omt_cursor_is_valid(cursor->omtcursor)) {
+	{
+	    int rr = toku_read_and_pin_brt_header(cursor->brt->cf, &cursor->brt->h);
+	    if (rr!=0) return rr;
+	    uint64_t h_counter = cursor->brt->h->root_put_counter;
+	    rr = toku_unpin_brt_header(cursor->brt);
+	    assert(rr==0);
+	    if (h_counter != cursor->root_put_counter) return -1;
+	}
+	OMTVALUE le;
+        u_int32_t index = UINT32_MAX;
+        int r = toku_omt_cursor_current_index(cursor->omtcursor, &index);
+        assert(r==0);
+        OMT omt = toku_omt_cursor_get_omt(cursor->omtcursor);
+get_next:;
+        if (++index<toku_omt_size(omt)) {
+            r = toku_omt_fetch(omt, index, &le, NULL); 
+            if (r==0) {
+                if (le_is_provdel(le)) goto get_next;
+                toku_fill_dbt(outkey, le_latest_key(le), le_latest_keylen(le));
+                toku_fill_dbt(outval, le_latest_val(le), le_latest_vallen(le));
+                return 0;
+            }
+        }
+    }
+    return -1;
+}
+
 static int brt_cursor_next(BRT_CURSOR cursor, DBT *outkey, DBT *outval, TOKULOGGER logger) {
     if (0!=(cursor->brt->flags & TOKU_DB_DUP) &&
 	brt_cursor_next_shortcut(cursor, outkey, outval)==0)
@@ -3330,6 +3388,12 @@ static int brt_cursor_next(BRT_CURSOR cursor, DBT *outkey, DBT *outval, TOKULOGG
     return brt_cursor_search(cursor, &search, outkey, outval, logger);
 }
 
+int toku_brt_cursor_after(BRT_CURSOR cursor, DBT *key, DBT *val, DBT *outkey, DBT *outval, TOKUTXN txn) {
+    TOKULOGGER logger = toku_txn_logger(txn);
+    brt_search_t search; brt_search_init(&search, brt_cursor_compare_next, BRT_SEARCH_LEFT, key, val, cursor->brt);
+    return brt_cursor_search(cursor, &search, outkey, outval, logger);
+}
+
 static int brt_cursor_compare_next_nodup(brt_search_t *search, DBT *x, DBT *y) {
     BRT brt = search->context; y = y;
     return compare_k_x(brt, search->k, x) < 0; /* return min x: k < x */
@@ -3413,6 +3477,12 @@ get_prev:;
     return -1;
 }
 
+int toku_brt_cursor_before(BRT_CURSOR cursor, DBT *key, DBT *val, DBT *outkey, DBT *outval, TOKUTXN txn) {
+    TOKULOGGER logger = toku_txn_logger(txn);
+    brt_search_t search; brt_search_init(&search, brt_cursor_compare_prev, BRT_SEARCH_RIGHT, key, val, cursor->brt);
+    return brt_cursor_search(cursor, &search, outkey, outval, logger);
+}
+
 static int brt_cursor_prev(BRT_CURSOR cursor, DBT *outkey, DBT *outval, TOKULOGGER logger) {
     if (0!=(cursor->brt->flags & TOKU_DB_DUP) &&
 	brt_cursor_prev_shortcut(cursor, outkey, outval)==0)
@@ -3543,6 +3613,34 @@ int toku_brt_cursor_get (BRT_CURSOR cursor, DBT *key, DBT *val, int get_flags, T
     return r;
 }
 
+static int brt_cursor_compare_heavi(brt_search_t *search, DBT *x, DBT *y) {
+    HEAVI_WRAPPER wrapper = search->context; 
+    int r = wrapper->h(x, y, wrapper->extra_h);
+    // wrapper->r_h must have the same signus as the final chosen element.
+    // it is initialized to -1 or 1.  0's are closer to the min (max) that we
+    // want so once we hit 0 we keep it.
+    if (r==0) wrapper->r_h = 0;
+    return (search->direction&BRT_SEARCH_LEFT) ? r>=0 : r<=0;
+}
+
+//We pass in toku_dbt_fake to the search functions, since it will not pass the
+//key(or val) to the heaviside function if key(or val) is NULL. 
+//It is not used for anything else,
+//the actual 'extra' information for the heaviside function is inside the
+//wrapper.
+static const DBT __toku_dbt_fake;
+static const DBT* const toku_dbt_fake = &__toku_dbt_fake;
+
+int toku_brt_cursor_get_heavi (BRT_CURSOR cursor, DBT *outkey, DBT *outval, TOKUTXN txn, int direction, HEAVI_WRAPPER wrapper) {
+    TOKULOGGER logger = toku_txn_logger(txn);
+    brt_search_t search; brt_search_init(&search, brt_cursor_compare_heavi,
+                                         direction < 0 ? BRT_SEARCH_RIGHT : BRT_SEARCH_LEFT,
+                                         (DBT*)toku_dbt_fake,
+                                         cursor->brt->flags & TOKU_DB_DUPSORT ? (DBT*)toku_dbt_fake : NULL,
+                                         wrapper);
+    return brt_cursor_search(cursor, &search, outkey, outval, logger);
+}
+
 static void toku_brt_keyrange_internal (BRT brt, CACHEKEY nodename, u_int32_t fullhash, DBT *key, u_int64_t *less,  u_int64_t *equal,  u_int64_t *greater) {
     BRTNODE node;
     {
diff --git a/newbrt/brt.h b/newbrt/brt.h
index 70147b07895..795421694d9 100644
--- a/newbrt/brt.h
+++ b/newbrt/brt.h
@@ -49,6 +49,17 @@ int toku_verify_brt (BRT brt);
 typedef struct brt_cursor *BRT_CURSOR;
 int toku_brt_cursor (BRT, BRT_CURSOR*, int is_temporary_cursor);
 int toku_brt_cursor_get (BRT_CURSOR cursor, DBT *kbt, DBT *vbt, int brtc_flags, TOKUTXN);
+struct heavi_wrapper {
+    int (*h)(const DBT *key, const DBT *value, void *extra_h);
+    void *extra_h;
+    int r_h;
+};
+typedef struct heavi_wrapper *HEAVI_WRAPPER;
+int toku_brt_cursor_get_heavi (BRT_CURSOR cursor, DBT *outkey, DBT *outval, TOKUTXN txn, int direction, HEAVI_WRAPPER wrapper);
+int toku_brt_cursor_peek_prev(BRT_CURSOR cursor, DBT *outkey, DBT *outval);
+int toku_brt_cursor_peek_next(BRT_CURSOR cursor, DBT *outkey, DBT *outval);
+int toku_brt_cursor_before(BRT_CURSOR cursor, DBT *key, DBT *val, DBT *outkey, DBT *outval, TOKUTXN txn);
+int toku_brt_cursor_after(BRT_CURSOR cursor, DBT *key, DBT *val, DBT *outkey, DBT *outval, TOKUTXN txn);
 int toku_brt_cursor_delete(BRT_CURSOR cursor, int flags, TOKUTXN);
 int toku_brt_cursor_close (BRT_CURSOR curs);
 BOOL toku_brt_cursor_uninitialized(BRT_CURSOR c);
diff --git a/newbrt/omt.c b/newbrt/omt.c
index a1f74548a18..464c5e2e1ef 100644
--- a/newbrt/omt.c
+++ b/newbrt/omt.c
@@ -80,6 +80,10 @@ int toku_omt_cursor_create (OMTCURSOR *omtcp) {
     return 0;
 }
 
+OMT toku_omt_cursor_get_omt(OMTCURSOR c) {
+    return c->omt;
+}
+
 void toku_omt_cursor_invalidate (OMTCURSOR c) {
     if (c==NULL || c->omt==NULL) return;
     if (c->next == c) {
@@ -625,6 +629,12 @@ int toku_omt_cursor_current (OMTCURSOR c, OMTVALUE *v) {
     return r;
 }
 
+int toku_omt_cursor_current_index(OMTCURSOR c, u_int32_t *index) {
+    if (c->omt == NULL) return EINVAL;
+    *index = c->index;
+    return 0;
+} 
+
 //TODO: Put all omt API functions here.
 int toku_omt_create (OMT *omtp) {
     return omt_create_internal(omtp, 2);
diff --git a/newbrt/omt.h b/newbrt/omt.h
index 007d70462e1..053d8a469d9 100644
--- a/newbrt/omt.h
+++ b/newbrt/omt.h
@@ -417,6 +417,19 @@ int toku_omt_cursor_next (OMTCURSOR c, OMTVALUE *v);
 // Performance:  time=O(log N) worst case, expected time=O(1) for a randomly
 //  chosen initial position.
 
+int toku_omt_cursor_current_index(OMTCURSOR c, u_int32_t *index);
+// Effect: Stores c's offset in *index.
+// Requires: index != NULL
+// Returns
+//  0 success
+//  EINVAL c is invalid
+// On nonzero return, *index is unchanged and c is unchanged.
+// Performance: time=O(1)
+
+OMT toku_omt_cursor_get_omt(OMTCURSOR c);
+// Effect: returns the associated omt or NULL if not associated.
+// Performance: time=O(1)
+
 int toku_omt_cursor_current (OMTCURSOR c, OMTVALUE *v);
 // Effect: Store in v the value pointed by c's abstract offset
 // Requires: v != NULL
diff --git a/src/tests/test_db_txn_locks.c b/src/tests/test_db_txn_locks.c
index 7613cb5e7c9..47b34c582d9 100644
--- a/src/tests/test_db_txn_locks.c
+++ b/src/tests/test_db_txn_locks.c
@@ -9,6 +9,37 @@
 
 #include "test.h"
 
+struct heavi_extra {
+    DBT key;
+    DBT val;
+    DB* db;
+};
+
+int heavi_after(const DBT *key, const DBT *val, void *extra) {
+    //Assumes cmp is int_dbt_cmp
+    struct heavi_extra *info = extra;
+    int cmp = int_dbt_cmp(info->db, key, &info->key);
+    if (cmp!=0) return cmp;
+    if (!val) return -1;
+    cmp = int_dbt_cmp(info->db, val, &info->val);
+    return cmp<=0 ? -1 : 0;
+    //Returns <0 for too small/equal
+    //Returns 0 for greater, but with the same key
+    //Returns >0 for greater with different key
+}
+
+int heavi_before(const DBT *key, const DBT *val, void *extra) {
+    struct heavi_extra *info = extra;
+    int cmp = int_dbt_cmp(info->db, key, &info->key);
+    if (cmp!=0) return cmp;
+    if (!val) return +1;
+    cmp = int_dbt_cmp(info->db, val, &info->val);
+    return cmp>=0 ? 1 : 0;
+    //Returns >0 for too large/equal
+    //Returns 0 for smaller with same key
+    //returns -1 for smaller with different key
+}
+
 // ENVDIR is defined in the Makefile
 
 int dbtcmp(DBT *dbt1, DBT *dbt2) {
@@ -593,6 +624,162 @@ void test_current(u_int32_t dup_flags) {
     close_dbs();
 }
 
+struct dbt_pair {
+    DBT key;
+    DBT val;
+};
+
+struct int_pair {
+    int key;
+    int val;
+};
+
+int got_r_h;
+
+void f_heavi(DBT const *key, DBT const *val, void *extra_f, int r_h) {
+    struct int_pair *info = extra_f;
+
+    if (r_h==0) got_r_h = 0;
+    assert(key->size == 4);
+    assert(val->size == 4);
+    
+    info->key = *(int*)key->data;
+    info->val = *(int*)val->data;
+}
+
+void cget_heavi(BOOL success, BOOL find, char txn, int _key, int _val, 
+          int _key_expect, int _val_expect, int direction,
+          int r_h_expect,
+          int (*h)(const DBT*,const DBT*,void*)) {
+#if defined(USE_BDB)
+    return;
+#else
+    assert(txns[(int)txn] && cursors[(int)txn]);
+
+    int r;
+    struct heavi_extra input;
+    struct int_pair output;
+    dbt_init(&input.key, &_key, sizeof(int));
+    dbt_init(&input.val, &_val, sizeof(int));
+    input.db = db;
+    output.key = 0;
+    output.val = 0;
+    
+    got_r_h = direction;
+
+    r = cursors[(int)txn]->c_getf_heavi(cursors[(int)txn], 0, //No prelocking
+               f_heavi, &output,
+               h, &input, direction);
+    if (!success) {
+        CKERR2s(r, DB_LOCK_DEADLOCK, DB_LOCK_NOTGRANTED);
+        return;
+    }
+    if (!find) {
+        CKERR2s(r,  DB_NOTFOUND, DB_KEYEMPTY);
+        return;
+    }
+    CKERR(r);
+    assert(got_r_h == r_h_expect);
+    assert(output.key == _key_expect);
+    assert(output.val == _val_expect);
+#endif
+}
+
+
+void test_heavi(u_int32_t dup_flags) {
+    /* ********************************************************************** */
+    setup_dbs(dup_flags);
+    cget_heavi(TRUE, FALSE, 'a', 0, 0, 0, 0,  1, 0, heavi_after); 
+    cget_heavi(TRUE, FALSE, 'a', 0, 0, 0, 0, -1, 0, heavi_before); 
+    close_dbs();
+    /* ********************************************************************** */
+    //Not found locks left to right (with empty db == entire db)
+    setup_dbs(dup_flags);
+    cget_heavi(TRUE, FALSE, 'a', 0, 0, 0, 0,  1, 0, heavi_after); 
+    put(FALSE, 'b', 7, 6);
+    put(FALSE, 'b', -1, -1);
+    put(TRUE,  'a', 4, 4);
+    early_commit('a');
+    put(TRUE, 'b', 7, 6);
+    put(TRUE, 'b', -1, -1);
+    close_dbs();
+    /* ********************************************************************** */
+    //Not found locks left to right (with empty db == entire db)
+    setup_dbs(dup_flags);
+    cget_heavi(TRUE, FALSE, 'a', 0, 0, 0, 0, -1, 0, heavi_before); 
+    put(FALSE, 'b', 7, 6);
+    put(FALSE, 'b', -1, -1);
+    put(TRUE,  'a', 4, 4);
+    early_commit('a');
+    put(TRUE, 'b', 7, 6);
+    put(TRUE, 'b', -1, -1);
+    close_dbs();
+    /* ********************************************************************** */
+    //Duplicate mode behaves differently.
+    setup_dbs(dup_flags);
+    int k,v;
+    for (k = 10; k <= 100; k+= 10) {
+        v = k+5;
+        put(TRUE, 'a', k, v);
+    }
+    if (dup_flags) {
+        cget_heavi(TRUE, TRUE, 'a', 100, 0, 100, 105,  1, 0, heavi_after); 
+    }
+    else {
+        cget_heavi(TRUE, FALSE, 'a', 100, 0, 0, 0,  1, 0, heavi_after); 
+    }
+    close_dbs();
+    /* ********************************************************************** */
+    //Locks stop at actual elements in the DB.
+    setup_dbs(dup_flags);
+    //int k,v;
+    for (k = 10; k <= 100; k+= 10) {
+        v = k+5;
+        put(TRUE, 'a', k, v);
+    }
+    cget_heavi(TRUE, FALSE, 'a', 105, 1, 0, 0,  1, 0, heavi_after); 
+    put(FALSE, 'b', 104, 1);
+    put(FALSE, 'b', 105, 0);
+    put(FALSE, 'b', 105, 1);
+    put(FALSE, 'b', 105, 2);
+    put(FALSE, 'b', 106, 0);
+    put(TRUE,  'b', 99,  0);
+    put(dup_flags!=0, 'b', 100, 104);
+    close_dbs();
+    /* ********************************************************************** */
+    // Test behavior of heavi_after
+    setup_dbs(dup_flags);
+    //int k,v;
+    for (k = 10; k <= 100; k+= 10) {
+        v = k+5;
+        put(TRUE, 'a', k, v);
+    }
+    for (k = 5; k <= 95; k+= 10) {
+        v = k+5;
+        cget_heavi(TRUE, TRUE, 'a', k, v, k+5, v+5,  1, 1, heavi_after); 
+    }
+    put(FALSE, 'b', -1, -2);
+    put(TRUE, 'b', 200, 201);
+    cget_heavi(FALSE, FALSE, 'a', 105, 105, 0, 0, 1, 0, heavi_after);
+    close_dbs();
+    /* ********************************************************************** */
+    // Test behavior of heavi_before
+    setup_dbs(dup_flags);
+    //int k,v;
+    for (k = 10; k <= 100; k+= 10) {
+        v = k+5;
+        put(TRUE, 'a', k, v);
+    }
+    for (k = 105; k >= 15; k-= 10) {
+        v = k+5;
+        cget_heavi(TRUE, TRUE, 'a', k, v, k-5, v-5,  -1, -1, heavi_before); 
+    }
+    put(FALSE, 'b', 200, 201);
+    put(TRUE,  'b', -1, -2);
+    cget_heavi(FALSE, FALSE, 'a', -5, -5, 0, 0, -1, 0, heavi_after);
+    close_dbs();
+}
+
 void test(u_int32_t dup_flags) {
     /* ********************************************************************** */
     setup_dbs(dup_flags);
@@ -637,6 +824,9 @@ void test(u_int32_t dup_flags) {
     test_dbdel(dup_flags);
     /* ********************************************************************** */
     test_current(dup_flags);
+    /* ********************************************************************** */
+    test_heavi(dup_flags);
+    /* ********************************************************************** */
 }
 
 
diff --git a/src/ydb.c b/src/ydb.c
index f986a95da62..2d96a5471a0 100644
--- a/src/ydb.c
+++ b/src/ydb.c
@@ -92,6 +92,146 @@ static int toku_db_cursor(DB *db, DB_TXN * txn, DBC **c, u_int32_t flags, int is
 /* lightweight cursor methods. */
 static int toku_c_getf_next(DBC *c, u_int32_t flag, void(*f)(DBT const *key, DBT const *data, void *extra), void *extra);
 
+static int toku_c_getf_heavi(DBC *c, u_int32_t flags,
+                             void(*f)(DBT const *key, DBT const *value, void *extra_f, int r_h),
+                             void *extra_f,
+                             int (*h)(const DBT *key, const DBT *value, void *extra_h),
+                             void *extra_h, int direction); 
+// There is a total order on all key/value pairs in the database.
+// In a DB_DUPSORT db, let V_i = (Key,Value) refer to the ith element (0 based indexing).
+// In a NODUP      db, let V_i = (Key)       refer to the ith element (0 based indexing).
+// We define V_{-1}             = -\infty and
+//           V_{|V|}            =  \infty and
+//           h(-\infty,extra_h) = -1 by definition and
+//           h( \infty,extra_h) =  1 by definition
+// Requires: Direction != 0
+// Effect: 
+//    if direction >0 then find the smallest i such that h(V_i,extra_h)>=0.
+//    if direction <0 then find the largest  i such that h(V_i,extra_h)<=0.
+//    Let signus(r_h) = signus(h(V_i, extra_h)) 
+//    If flags&(DB_PRELOCKED|DB_PRELOCKED_WRITE) then skip locking
+//      That is, we already own the locks
+//    else 
+//      if direction >0 then readlock [V_{i-1}, V_i]
+//      if direction <0 then readlock [V_i,     V_{i+1}]
+//      That is, If we search from the right, lock the element we found, up to the
+//           next element to the right.
+//      If locking fails, return the locking error code
+//    
+//    If (0<=i<|V|) then
+//      call f(V_i.Key, V_i.Value, extra_f, r_h)
+//      Note: The lifetime of V_i.Key and V_i.Value is limited: they may only
+//            be referenced until f returns
+//      and return 0
+//    else
+//      return DB_NOTFOUND
+// Rationale: Locking
+//      If we approach from the left (direction<0) we need to prevent anyone
+//      from inserting anything to our right that could change our answer,
+//      so we lock the range from the element found, to the next element to the right.
+//      The inverse argument applies for approaching from the right.
+// Rationale: passing r_h to f
+//      We want to save the performance hit of requiring f to call h again to
+//      find out what h's return value was.
+// Rationale: separate extra_f, extra_h parameters
+//      If the same extra parameter is sent to both f and h, then you need a
+//      special struct for each tuple (f_i, h_i) you use instead of a struct for each
+//      f_i and each h_i.
+// Requires: The signum of h is monotically increasing.
+//  Requires: f does not create references to key, value, or data within once f
+//           exits
+// Returns
+//      0                   success
+//      DB_NOTFOUND         i is not in [0,|V|)
+//      DB_LOCK_NOTGRANTED  Failed to obtain a lock.
+//  On nonzero return, what c points to becomes undefined, That is, c becomes uninitialized
+// Performance: ... TODO
+// Implementation Notes:
+//      How do we get the extra locking information efficiently?
+//        After finding the target, we can copy the cursor, do a DB_NEXT,
+//        or do a DB_NEXT+DB_PREV (vice versa for direction<0).
+//        Can we have the BRT provide two key/value pairs instead of one?
+//        That is, brt_cursor_c_getf_heavi_and_next for direction >0
+//        and  brt_cursor_c_getf_heavi_and_prev for direction <0
+//      Current suggestion is to make a copy of the cursor, and use the
+//        copy to find the next(prev) element by using DB_NEXT(DB_PREV).
+//        This has the overhead of needing to make a copy of the cursor,
+//        which probably has a memcpy involved.
+//        The argument against returning two key/value pairs is that
+//        we should not have to pay to retreive both when we're doing something
+//        simple like DB_NEXT.
+//        This could be mitigated by having two BRT functions (or one with a
+//        BOOL parameter) such that it only returns two values when necessary.
+// Parameters
+//  c           The cursor
+//  flags       Additional bool parameters. The current allowed flags are
+//              DB_PRELOCKED and DB_PRELOCKED_WRITE (bitwise or'd to use both)
+//  h           A heaviside function that, along with direction, defines the query.
+//              extra_h is passed to h
+//              For additional information on heaviside functions, see omt.h
+//              NOTE: In a DB_DUPSORT database, both key and value will be
+//              passed to h.  In a NODUP database, only key will be passed to h.
+//  f           A callback function (i.e. smart dbts) to provide the result of the
+//              query.  key and value are the key/value pair found, extra_f is
+//              passed to f, r_h is the return value for h for the key and value returned.
+//              This is used as output. That is, we call f with the outputs of the
+//              function.
+//  direction   Which direction to search in on the heaviside function.  >0
+//              means from the right, <0 means from the left.
+//  extra_f     Any extra information required for f
+//  extra_h     Any extra information required for h
+//
+// Example:
+//  Find the smallest V_i = (key_i,val_i) such that key_i > key_x, assume
+//   key.data and val.data are c strings, and print them out.
+//      Create a struct to hold key_x, that is extra_h
+//      Direction = 1 (We approach from the right, and want the smallest such
+//          element).
+//      Construct a heaviside function that returns >=0 if the
+//      given key > key_x, and -1 otherwise
+//          That is, call the comparison function on (key, key_x)
+//      Create a struct to hold key_x, that is extra_f
+//      construct f to call printf on key_x.data, key_i.data, val_i.data.
+//  Find the least upper bound (greatest lower bound)
+//      In this case, h can just return the comparison function's answer.
+//      direction >0 means upper bound, direction <0 means lower bound.
+//      (If you want upper/lower bound of the keyvalue pair, you need
+//      to call the comparison function on the values if the key comparison
+//      returns 0).
+// Handlerton implications:
+//  The handlerton needs at most one heaviside function per special query type (where a
+//  special query is one that is not directly supported by the bdb api excluding
+//  this function).
+//  It is possible that more than query type can use the same heaviside function
+//  if the extra_h parameter can be used to change its behavior sufficiently.
+//
+//  That is, part of extra_h can be a boolean strictly_greater
+//  You can construct a single heaviside function that converts 0 to -1
+//  (strictly greater) from the comparison function, or one that just returns
+//  the results of the comparison function (greater or equal).
+//
+// Implementation Notes:
+//  The BRT search function supports the following searches:
+//      SEARCH_LEFT(h(V_i))
+//          Given a step function b, that goes from 0 to 1
+//          find the greatest i such that h_b(V_i) == 1
+//          If it does not exist, return not found
+//      SEARCH_RIGHT(h(V_i))
+//          Given a step function b, that goes from 1 to 0
+//          find the smallest i such that h_b(V_i) == 1
+//          If it does not exist, return not found
+//  We can implement c_getf_heavi using these BRT search functions.
+//  A query of direction<0:
+//      Create wrapper function B
+//          return h(V_i) <=0 ? 1 : 0;
+//      SEARCH_RIGHT(B)
+//  A query of direction>0:
+//      Create wrapper function B
+//          return h(V_i) >=0 ? 1 : 0;
+//      SEARCH_LEFT(B)
+
+// Effect: Lightweight cursor get
+
 /* cursor methods */
 static int toku_c_get(DBC * c, DBT * key, DBT * data, u_int32_t flag);
 static int toku_c_get_noassociate(DBC * c, DBT * key, DBT * data, u_int32_t flag);
@@ -1639,7 +1779,6 @@ static int toku_c_getf_next_old(DBC *c, u_int32_t flag, void(*f)(DBT const *key,
 
 static int toku_c_getf_next(DBC *c, u_int32_t flag, void(*f)(DBT const *key, DBT const *data, void *extra), void *extra) {
     HANDLE_PANICKED_DB(c->dbp);
-    //int prelocked = flag & DB_PRELOCKED;
     if (toku_c_uninitialized(c)) return toku_c_getf_next_old(c, flag, f, extra); //return toku_c_getf_first(c, flag, f, extra);
     u_int32_t lock_flags = get_prelocked_flags(flag);
     flag &= ~lock_flags;
@@ -1684,6 +1823,130 @@ static int toku_c_getf_next(DBC *c, u_int32_t flag, void(*f)(DBT const *key, DBT
     return r;
 }
 
+static int locked_c_getf_heavi(DBC *c, u_int32_t flags,
+                               void(*f)(DBT const *key, DBT const *value, void *extra_f, int r_h),
+                               void *extra_f,
+                               int (*h)(const DBT *key, const DBT *value, void *extra_h),
+                               void *extra_h, int direction) {
+    toku_ydb_lock();  int r = toku_c_getf_heavi(c, flags, f, extra_f, h, extra_h, direction); toku_ydb_unlock(); return r;
+}
+
+static int toku_c_getf_heavi(DBC *c, u_int32_t flags,
+                             void(*f)(DBT const *key, DBT const *value, void *extra_f, int r_h),
+                             void *extra_f,
+                             int (*h)(const DBT *key, const DBT *value, void *extra_h),
+                             void *extra_h, int direction) {
+    if (direction==0) return EINVAL;
+    DBC *tmp_c = NULL;
+    int r;
+    u_int32_t lock_flags = get_prelocked_flags(flags);
+    flags &= ~lock_flags;
+    assert(flags==0);
+    struct heavi_wrapper wrapper;
+    wrapper.h       = h;
+    wrapper.extra_h = extra_h;
+    wrapper.r_h     = direction;
+
+    TOKUTXN txn = c->i->txn ? c->i->txn->i->tokutxn : NULL;
+    int c_get_result = toku_brt_cursor_get_heavi(c->i->c, NULL, NULL, txn, direction, &wrapper);
+    if (c_get_result!=0 && c_get_result!=DB_NOTFOUND) { r = c_get_result; goto cleanup; }
+    BOOL found = c_get_result==0;
+    DB *db=c->dbp;
+    toku_lock_tree* lt = db->i->lt;
+    if (lt!=NULL && !lock_flags) {
+        DBT tmp_key;
+        DBT tmp_val;
+        DBT *left_key, *left_val, *right_key, *right_val;
+        if (direction<0) {
+            if (!found) {
+                r = toku_brt_cursor_get(c->i->c, NULL, NULL, DB_FIRST, txn);
+                if (r!=0 && r!=DB_NOTFOUND) goto cleanup;
+                if (r==DB_NOTFOUND) right_key = right_val = (DBT*)toku_lt_infinity;
+                else {
+                    //Restore cursor to the 'uninitialized' state it was just in.
+                    brt_cursor_restore_state_from_prev(c->i->c);
+                    right_key = brt_cursor_peek_prev_key(c->i->c);
+                    right_val = brt_cursor_peek_prev_val(c->i->c);
+                }
+                left_key = left_val = (DBT*)toku_lt_neg_infinity;
+            }
+            else {
+                left_key = brt_cursor_peek_current_key(c->i->c);
+                left_val = brt_cursor_peek_current_val(c->i->c);
+                //Try to find right end the fast way.
+                r = toku_brt_cursor_peek_next(c->i->c, &tmp_key, &tmp_val);
+                if (r==0) {
+                    right_key = &tmp_key;
+                    right_val = &tmp_val;
+                }
+                else {
+                    //Find the right end the slow way.
+                    if ((r = toku_db_cursor(c->dbp, c->i->txn, &tmp_c, 0, 0))) goto cleanup;
+                    r=toku_brt_cursor_after(tmp_c->i->c, left_key, left_val,
+                                                         NULL,     NULL, txn);
+                    if (r!=0 && r!=DB_NOTFOUND) goto cleanup;
+                    if (r==DB_NOTFOUND) right_key = right_val = (DBT*)toku_lt_infinity;
+                    else {
+                        right_key = brt_cursor_peek_current_key(tmp_c->i->c);
+                        right_val = brt_cursor_peek_current_val(tmp_c->i->c);
+                    }
+                }
+            }
+        }
+        else {
+            //direction>0
+            if (!found) {
+                r = toku_brt_cursor_get(c->i->c, NULL, NULL, DB_LAST, txn);
+                if (r!=0 && r!=DB_NOTFOUND) goto cleanup;
+                if (r==DB_NOTFOUND) left_key = left_val = (DBT*)toku_lt_neg_infinity;
+                else {
+                    //Restore cursor to the 'uninitialized' state it was just in.
+                    brt_cursor_restore_state_from_prev(c->i->c);
+                    left_key = brt_cursor_peek_prev_key(c->i->c);
+                    left_val = brt_cursor_peek_prev_val(c->i->c);
+                }
+                right_key = right_val = (DBT*)toku_lt_infinity;
+            }
+            else {
+                right_key = brt_cursor_peek_current_key(c->i->c);
+                right_val = brt_cursor_peek_current_val(c->i->c);
+                //Try to find left end the fast way.
+                r=toku_brt_cursor_peek_prev(c->i->c, &tmp_key, &tmp_val);
+                if (r==0) {
+                    left_key = &tmp_key;
+                    left_val = &tmp_val;
+                }
+                else {
+                    //Find the left end the slow way.
+                    if ((r = toku_db_cursor(c->dbp, c->i->txn, &tmp_c, 0, 0))) goto cleanup;
+                    r=toku_brt_cursor_before(tmp_c->i->c, right_key, right_val,
+                                                          NULL,      NULL, txn);
+                    if (r==DB_NOTFOUND) left_key = left_val = (DBT*)toku_lt_neg_infinity;
+                    else {
+                        left_key = brt_cursor_peek_current_key(tmp_c->i->c);
+                        left_val = brt_cursor_peek_current_val(tmp_c->i->c);
+                    }
+                }
+            }
+        }
+        DB_TXN* txn_anc = toku_txn_ancestor(c->i->txn);
+        TXNID id_anc = toku_txn_get_txnid(txn_anc->i->tokutxn);
+        if ((r = toku_txn_add_lt(txn_anc, lt))) goto cleanup;
+        r = toku_lt_acquire_range_read_lock(lt, db, id_anc,
+                                            left_key, left_val,
+                                            right_key, right_val);
+        if (r!=0) goto cleanup;
+    }
+    if (found) {
+        f(brt_cursor_peek_current_key(c->i->c), brt_cursor_peek_current_val(c->i->c), extra_f, wrapper.r_h);
+    }
+    r = c_get_result;
+cleanup:;
+    int r2 = 0;
+    if (tmp_c) r2 = toku_c_close(tmp_c);
+    return r ? r : r2;
+}
+
 static int toku_c_close(DBC * c) {
     int r = toku_brt_cursor_close(c->i->c);
     toku_free(c->i);
@@ -1987,13 +2250,16 @@ static int toku_db_cursor(DB * db, DB_TXN * txn, DBC ** c, u_int32_t flags, int
     if (result == 0)
         return ENOMEM;
     memset(result, 0, sizeof *result);
-    result->c_get = locked_c_get;
-    result->c_pget = locked_c_pget;
-    result->c_put = locked_c_put;
-    result->c_close = locked_c_close;
-    result->c_del = locked_c_del;
-    result->c_count = locked_c_count;
-    result->c_getf_next = locked_c_getf_next;
+#define SCRS(name) result->name = locked_ ## name
+    SCRS(c_get);
+    SCRS(c_pget);
+    SCRS(c_put);
+    SCRS(c_close);
+    SCRS(c_del);
+    SCRS(c_count);
+    SCRS(c_getf_next);
+    SCRS(c_getf_heavi);
+#undef SCRS
     MALLOC(result->i);
     assert(result->i);
     result->dbp = db;