diff --git a/src/multi_skiplist.c b/src/multi_skiplist.c
index eaa47e6..15cc32c 100644
--- a/src/multi_skiplist.c
+++ b/src/multi_skiplist.c
@@ -18,7 +18,8 @@
 #include "multi_skiplist.h"
 
 int multi_skiplist_init_ex(MultiSkiplist *sl, const int level_count,
-        multi_skiplist_compare_func compare_func, const int min_alloc_elements_once)
+        multi_skiplist_compare_func compare_func,
+        const int min_alloc_elements_once)
 {
     int bytes;
     int element_size;
@@ -223,7 +224,7 @@ int multi_skiplist_insert(MultiSkiplist *sl, void *data)
 }
 
 int multi_skiplist_do_delete(MultiSkiplist *sl, void *data,
-        const bool delete_all)
+        const bool delete_all, int *delete_count)
 {
     int i;
     int level_index;
@@ -232,6 +233,7 @@ int multi_skiplist_do_delete(MultiSkiplist *sl, void *data,
     MultiSkiplistData *dataNode;
     MultiSkiplistData *dataCurrent;
 
+    *delete_count = 0;
     previous = multi_skiplist_get_previous(sl, data, &level_index);
     if (previous == NULL) {
         return ENOENT;
@@ -243,6 +245,7 @@ int multi_skiplist_do_delete(MultiSkiplist *sl, void *data,
             dataNode = deleted->head;
             deleted->head = dataNode->next;
             fast_mblock_free_object(&sl->data_mblock, dataNode);
+            *delete_count = 1;
             return 0;
         }
     }
@@ -261,6 +264,8 @@ int multi_skiplist_do_delete(MultiSkiplist *sl, void *data,
     while (dataCurrent != NULL) {
         dataNode = dataCurrent;
         dataCurrent = dataCurrent->next;
+
+        (*delete_count)++;
         fast_mblock_free_object(&sl->data_mblock, dataNode);
     }
 
@@ -270,12 +275,13 @@ int multi_skiplist_do_delete(MultiSkiplist *sl, void *data,
 
 int multi_skiplist_delete(MultiSkiplist *sl, void *data)
 {
-    return multi_skiplist_do_delete(sl, data, false);
+    int delete_count;
+    return multi_skiplist_do_delete(sl, data, false, &delete_count);
 }
 
-int multi_skiplist_delete_all(MultiSkiplist *sl, void *data)
+int multi_skiplist_delete_all(MultiSkiplist *sl, void *data, int *delete_count)
 {
-    return multi_skiplist_do_delete(sl, data, true);
+    return multi_skiplist_do_delete(sl, data, true, delete_count);
 }
 
 void *multi_skiplist_find(MultiSkiplist *sl, void *data)
@@ -287,3 +293,23 @@ void *multi_skiplist_find(MultiSkiplist *sl, void *data)
     return (previous != NULL) ? previous->links[level_index]->head->data : NULL;
 }
 
+int multi_skiplist_find_all(MultiSkiplist *sl, void *data,
+        MultiSkiplistIterator *iterator)
+{
+    int level_index;
+    MultiSkiplistNode *previous;
+
+    iterator->current.data = NULL;
+    previous = multi_skiplist_get_previous(sl, data, &level_index);
+    if (previous == NULL) {
+        iterator->current.node = sl->tail;
+        iterator->tail = sl->tail;
+        return ENOENT;
+    }
+    else {
+        iterator->current.node = previous;
+        iterator->tail = previous->links[0]->links[0];
+        return 0;
+    }
+}
+
diff --git a/src/multi_skiplist.h b/src/multi_skiplist.h
index f563123..30249e5 100644
--- a/src/multi_skiplist.h
+++ b/src/multi_skiplist.h
@@ -43,7 +43,7 @@ typedef struct multi_skiplist
 } MultiSkiplist;
 
 typedef struct multi_skiplist_iterator {
-    MultiSkiplist *sl;
+    MultiSkiplistNode *tail;
     struct {
         MultiSkiplistNode *node;
         MultiSkiplistData *data;
@@ -61,18 +61,22 @@ extern "C" {
     SKIPLIST_DEFAULT_MIN_ALLOC_ELEMENTS_ONCE)
 
 int multi_skiplist_init_ex(MultiSkiplist *sl, const int level_count,
-        multi_skiplist_compare_func compare_func, const int min_alloc_elements_once);
+        multi_skiplist_compare_func compare_func,
+        const int min_alloc_elements_once);
 
 void multi_skiplist_destroy(MultiSkiplist *sl);
 
 int multi_skiplist_insert(MultiSkiplist *sl, void *data);
 int multi_skiplist_delete(MultiSkiplist *sl, void *data);
-int multi_skiplist_delete_all(MultiSkiplist *sl, void *data);
+int multi_skiplist_delete_all(MultiSkiplist *sl, void *data, int *delete_count);
 void *multi_skiplist_find(MultiSkiplist *sl, void *data);
+int multi_skiplist_find_all(MultiSkiplist *sl, void *data,
+        MultiSkiplistIterator *iterator);
 
-static inline void multi_skiplist_iterator(MultiSkiplist *sl, MultiSkiplistIterator *iterator)
+static inline void multi_skiplist_iterator(MultiSkiplist *sl,
+        MultiSkiplistIterator *iterator)
 {
-    iterator->sl = sl;
+    iterator->tail = sl->tail;
     iterator->current.node = sl->top;
     iterator->current.data = NULL;
 }
@@ -82,8 +86,8 @@ static inline void *multi_skiplist_next(MultiSkiplistIterator *iterator)
     void *data;
 
     if (iterator->current.data == NULL) {
-        if (iterator->current.node == iterator->sl->tail ||
-                iterator->current.node->links[0] == iterator->sl->tail)
+        if (iterator->current.node == iterator->tail ||
+                iterator->current.node->links[0] == iterator->tail)
         {
             return NULL;
         }
diff --git a/src/skiplist.c b/src/skiplist.c
index f77ff71..1377e67 100644
--- a/src/skiplist.c
+++ b/src/skiplist.c
@@ -229,6 +229,16 @@ int skiplist_delete(Skiplist *sl, void *data)
     return 0;
 }
 
+int skiplist_delete_all(Skiplist *sl, void *data, int *delete_count)
+{
+    *delete_count = 0;
+    while (skiplist_delete(sl, data) == 0) {
+        (*delete_count)++;
+    }
+
+    return *delete_count > 0 ? 0 : ENOENT;
+}
+
 void *skiplist_find(Skiplist *sl, void *data)
 {
     int level_index;
@@ -238,3 +248,26 @@ void *skiplist_find(Skiplist *sl, void *data)
     return (previous != NULL) ? previous->links[level_index]->data : NULL;
 }
 
+int skiplist_find_all(Skiplist *sl, void *data, SkiplistIterator *iterator)
+{
+    int level_index;
+    SkiplistNode *previous;
+    SkiplistNode *last;
+
+    previous = skiplist_get_previous(sl, data, &level_index);
+    if (previous == NULL) {
+        iterator->top = sl->top;
+        iterator->current = sl->top;
+        return ENOENT;
+    }
+
+    last = previous->links[0]->links[0];
+    while (last != sl->tail && sl->compare_func(data, last->data) == 0) {
+        last = last->links[0];
+    }
+
+    iterator->top = previous;
+    iterator->current = last->prev;
+    return 0;
+}
+
diff --git a/src/skiplist.h b/src/skiplist.h
index 95849ee..6ee80be 100644
--- a/src/skiplist.h
+++ b/src/skiplist.h
@@ -36,7 +36,7 @@ typedef struct skiplist
 } Skiplist;
 
 typedef struct skiplist_iterator {
-    Skiplist *sl;
+    SkiplistNode *top;
     SkiplistNode *current;
 } SkiplistIterator;
 
@@ -57,11 +57,13 @@ void skiplist_destroy(Skiplist *sl);
 
 int skiplist_insert(Skiplist *sl, void *data);
 int skiplist_delete(Skiplist *sl, void *data);
+int skiplist_delete_all(Skiplist *sl, void *data, int *delete_count);
 void *skiplist_find(Skiplist *sl, void *data);
+int skiplist_find_all(Skiplist *sl, void *data, SkiplistIterator *iterator);
 
 static inline void skiplist_iterator(Skiplist *sl, SkiplistIterator *iterator)
 {
-    iterator->sl = sl;
+    iterator->top = sl->top;
     iterator->current = sl->tail->prev;
 }
 
@@ -69,7 +71,7 @@ static inline void *skiplist_next(SkiplistIterator *iterator)
 {
     void *data;
 
-    if (iterator->current == iterator->sl->top) {
+    if (iterator->current == iterator->top) {
         return NULL;
     }
 
diff --git a/src/tests/test_multi_skiplist.c b/src/tests/test_multi_skiplist.c
index a0dbf85..64a8039 100644
--- a/src/tests/test_multi_skiplist.c
+++ b/src/tests/test_multi_skiplist.c
@@ -10,7 +10,7 @@
 #include "logger.h"
 #include "shared_func.h"
 
-#define COUNT 1280000
+#define COUNT 12800
 #define LEVEL_COUNT 18
 #define MIN_ALLOC_ONCE  32
 #define LAST_INDEX (COUNT - 1)
@@ -106,15 +106,18 @@ static int compare_record(const void *p1, const void *p2)
 
 static int test_stable_sort()
 {
-#define RECORDS 20 
+#define RECORDS 32
     int i;
     int result;
     int index1;
     int index2;
+    int delete_count;
+    int total_delete_count;
     MultiSkiplist sl;
     MultiSkiplistIterator iterator;
     Record records[RECORDS];
     Record *record;
+    Record target;
     void *value;
 
     result = multi_skiplist_init_ex(&sl, 12, compare_record, 128);
@@ -153,7 +156,39 @@ static int test_stable_sort()
         record = (Record *)value;
         printf("%d => #%d\n", record->key, record->line);
     }
-    assert(i==RECORDS);
+    assert(i == RECORDS);
+
+    target.key = 10;
+    target.line = 0;
+    if (multi_skiplist_find_all(&sl, &target, &iterator) == 0) {
+        printf("found key: %d\n", target.key);
+    }
+    i = 0;
+    while ((value=multi_skiplist_next(&iterator)) != NULL) {
+        i++;
+        record = (Record *)value;
+        printf("%d => #%d\n", record->key, record->line);
+    }
+    printf("found record count: %d\n", i);
+
+    total_delete_count = 0;
+    for (i=0; i<RECORDS; i++) {
+        if ((result=multi_skiplist_delete_all(&sl, records + i,
+                        &delete_count)) == 0)
+        {
+            total_delete_count += delete_count;
+        }
+        assert((result == 0 && delete_count > 0) ||
+                (result != 0 && delete_count == 0));
+    }
+    assert(total_delete_count == RECORDS);
+
+    i = 0;
+    multi_skiplist_iterator(&sl, &iterator);
+    while ((value=multi_skiplist_next(&iterator)) != NULL) {
+        i++;
+    }
+    assert(i == 0);
 
     multi_skiplist_destroy(&sl);
     return 0;
diff --git a/src/tests/test_skiplist.c b/src/tests/test_skiplist.c
index aca468e..91bc728 100644
--- a/src/tests/test_skiplist.c
+++ b/src/tests/test_skiplist.c
@@ -10,7 +10,7 @@
 #include "logger.h"
 #include "shared_func.h"
 
-#define COUNT 1000
+#define COUNT 100000
 #define LEVEL_COUNT 18
 #define MIN_ALLOC_ONCE  32
 #define LAST_INDEX (COUNT - 1)
@@ -106,15 +106,18 @@ static int compare_record(const void *p1, const void *p2)
 
 static int test_stable_sort()
 {
-#define RECORDS 20 
+#define RECORDS 32
     int i;
     int result;
     int index1;
     int index2;
+    int delete_count;
+    int total_delete_count;
     Skiplist sl;
     SkiplistIterator iterator;
     Record records[RECORDS];
     Record *record;
+    Record target;
     void *value;
 
     result = skiplist_init_ex(&sl, 12, compare_record, 128);
@@ -155,6 +158,38 @@ static int test_stable_sort()
     }
     assert(i==RECORDS);
 
+    target.key = 10;
+    target.line = 0;
+    if (skiplist_find_all(&sl, &target, &iterator) == 0) {
+        printf("found key: %d\n", target.key);
+    }
+    i = 0;
+    while ((value=skiplist_next(&iterator)) != NULL) {
+        i++;
+        record = (Record *)value;
+        printf("%d => #%d\n", record->key, record->line);
+    }
+    printf("found record count: %d\n", i);
+
+    total_delete_count = 0;
+    for (i=0; i<RECORDS; i++) {
+        if ((result=skiplist_delete_all(&sl, records + i,
+                        &delete_count)) == 0)
+        {
+            total_delete_count += delete_count;
+        }
+        assert((result == 0 && delete_count > 0) ||
+                (result != 0 && delete_count == 0));
+    }
+    assert(total_delete_count == RECORDS);
+
+    i = 0;
+    skiplist_iterator(&sl, &iterator);
+    while ((value=skiplist_next(&iterator)) != NULL) {
+        i++;
+    }
+    assert(i == 0);
+
     skiplist_destroy(&sl);
     return 0;
 }