diff --git a/src/bitmap.c b/src/bitmap.c
index af28f60..d2a3b2f 100644
--- a/src/bitmap.c
+++ b/src/bitmap.c
@@ -45,9 +45,7 @@ static unsigned char dict[256] = {
 };
 
 int
-simdb_bitmap_compare(const unsigned char *a,
-                     const unsigned char *b)
-{
+simdb_bitmap_compare(const unsigned char *a, const unsigned char *b) {
   unsigned char diff = 0;
   size_t i = 0;
   size_t cnt = 0;
@@ -60,20 +58,6 @@ simdb_bitmap_compare(const unsigned char *a,
   return cnt;
 }
 
-size_t
-simdb_bitmap_diffmap(const unsigned char *a,
-                     const unsigned char *b,
-                     unsigned char *diff)
-{
-  size_t i = 0;
-
-  for (i = 0; i < SIMDB_BITMAP_SIZE; i++, a++, b++, diff++) {
-    *diff = *a ^ *b;
-  }
-
-  return i;
-}
-
 size_t
 simdb_bitmap_unpack(const unsigned char *map, char **buf) {
   size_t buf_size = SIMDB_BITMAP_BITS;
diff --git a/src/bitmap.h b/src/bitmap.h
index 05bda61..815caa9 100644
--- a/src/bitmap.h
+++ b/src/bitmap.h
@@ -19,22 +19,7 @@
  * @param b Second bitmap to compare
  * @returns Integer showing difference between bitmaps in bits (0-256)
  */
-int
-simdb_bitmap_compare(const unsigned char *a,
-                     const unsigned char *b);
-
-/**
- * @brief Make difference map of to bitmaps
- * @param a    First bitmap to compare
- * @param b    Second bitmap to compare
- * @param diff Storage for difference map
- * @returns Size of generated map (now is @a BITMAP_SIZE)
- */
-size_t
-simdb_bitmap_diffmap(const unsigned char *a,
-                     const unsigned char *b,
-                     unsigned char *diff);
-
+int simdb_bitmap_compare(const unsigned char *a, const unsigned char *b);
 
 /**
  * @brief Unpack BITmap to BYTEmap
@@ -42,6 +27,5 @@ simdb_bitmap_diffmap(const unsigned char *a,
  * @param buf Pointer to store generated bytemap
  * @returns Size of generated bytemap (now is @a BITMAP_BITS)
  */
-size_t
-simdb_bitmap_unpack(const unsigned char *map, char **buf);
+size_t simdb_bitmap_unpack(const unsigned char *map, char **buf);
 #endif
diff --git a/src/simdb-query.c b/src/simdb-query.c
index cb91102..dfff711 100644
--- a/src/simdb-query.c
+++ b/src/simdb-query.c
@@ -171,43 +171,55 @@ int rec_bitmap(simdb_t *db, int num) {
 }
 
 int rec_diff(simdb_t *db, int a, int b, unsigned short int showmap) {
-  unsigned char map[SIMDB_BITMAP_SIZE];
-  simdb_urec_t *one, *two;
-  float diff = 0.0;
+  char *map1 = NULL, *map2 = NULL, *dmap = NULL;
+  size_t size = 0, diff = 0;
   int ret;
 
   assert(db != NULL);
 
-  if ((ret = simdb_read(db, a, 1, &one)) < 0) {
-    fprintf(stderr, "read error: %s\n", simdb_error(ret));
-    return 1;
-  } else if (ret == 0 || (ret > 0 && !one->used)) {
-    fprintf(stderr, "record diff: first sample not exists\n");
-    if (ret > 0) free(one);
-    return 1;
-  }
+  do {
+    if ((ret = simdb_record_bitmap(db, a, &map1, &size)) < 0) {
+      if (ret < 0) {
+        fprintf(stderr, "can't get bitmap for record #%d: %s\n", a, simdb_error(ret));
+      } else {
+        fprintf(stderr, "record diff: record #%d not exists\n", a);
+      }
+      ret = 1;
+      break;
+    }
 
-  if ((ret = simdb_read(db, b, 1, &two)) < 0) {
-    fprintf(stderr, "read error: %s\n", simdb_error(ret));
-    return 1;
-  } else if (ret == 0 || (ret > 0 && !two->used)) {
-    fprintf(stderr, "record diff: first sample not exists\n");
-    if (ret > 0) free(two);
-    return 1;
-  }
+    if ((ret = simdb_record_bitmap(db, b, &map2, &size)) <= 0) {
+      if (ret < 0) {
+        fprintf(stderr, "can't get bitmap for record #%d: %s\n", b, simdb_error(ret));
+      } else {
+        fprintf(stderr, "record diff: record #%d not exists\n", b);
+      }
+      ret = 1;
+      break;
+    }
 
-  if (showmap) {
-    simdb_bitmap_diffmap(one->bitmap, two->bitmap, map);
-    bitmap_print(map, SIMDB_BITMAP_SIDE);
-    return 0;
-  }
+    if ((dmap = calloc(size, sizeof(char))) == NULL) {
+      ret = 1;
+      break;
+    }
+    char *m1 = map1, *m2 = map2, *dm = dmap;
+    for (size_t i = 0; i < size; i++, m1++, m2++, dm++) {
+      *dm = *m1 ^ *m2;
+      diff += *dm ? 0 : 1;
+    }
+    if (showmap) {
+      bitmap_print(dmap, size);
+    } else {
+      printf("%.2f%%\n", ((float) diff / size) * 100);
+    }
+    ret = 0;
+  } while (0);
 
-  diff = (float) simdb_bitmap_compare(one->bitmap, two->bitmap);
-  printf("%.2f%%\n", (diff / SIMDB_BITMAP_BITS) * 100);
-  free(one);
-  free(two);
+  free(map1);
+  free(map2);
+  free(dmap);
 
-  return 0;
+  return ret;
 }
 
 int main(int argc, char **argv)