diff --git a/osd_cluster.cpp b/osd_cluster.cpp
index 0ea16905..f3aca1a1 100644
--- a/osd_cluster.cpp
+++ b/osd_cluster.cpp
@@ -155,7 +155,6 @@ json11::Json osd_t::get_statistics()
         st["free"] = bs->get_free_block_count() * bs->get_block_size();
     }
     st["host"] = self_state["host"];
-    // FIXME: handle integer overflow
     json11::Json::object op_stats, subop_stats;
     for (int i = 0; i <= OSD_OP_MAX; i++)
     {
diff --git a/osd_primary.cpp b/osd_primary.cpp
index 02ee032c..fc14850f 100644
--- a/osd_primary.cpp
+++ b/osd_primary.cpp
@@ -247,6 +247,11 @@ resume_5:
         {
             int recovery_type = op_data->object_state->state & (OBJ_DEGRADED|OBJ_INCOMPLETE) ? 0 : 1;
             recovery_stat_count[0][recovery_type]++;
+            if (recovery_stat_count[0][recovery_type])
+            {
+                recovery_stat_count[0][recovery_type]++;
+                recovery_stat_bytes[0][recovery_type] = 0;
+            }
             for (int role = 0; role < pg.pg_size; role++)
             {
                 recovery_stat_bytes[0][recovery_type] += op_data->stripes[role].write_end - op_data->stripes[role].write_start;
diff --git a/osd_primary_subops.cpp b/osd_primary_subops.cpp
index 0e1a97d8..7af085c8 100644
--- a/osd_primary_subops.cpp
+++ b/osd_primary_subops.cpp
@@ -212,6 +212,12 @@ void osd_t::add_bs_subop_stats(osd_op_t *subop)
     timespec tv_end;
     clock_gettime(CLOCK_REALTIME, &tv_end);
     op_stat_count[0][opcode]++;
+    if (!op_stat_count[0][opcode])
+    {
+        op_stat_count[0][opcode] = 1;
+        op_stat_sum[0][opcode] = 0;
+        op_stat_bytes[0][opcode] = 0;
+    }
     op_stat_sum[0][opcode] += (
         (tv_end.tv_sec - subop->tv_begin.tv_sec)*1000000 +
         (tv_end.tv_nsec - subop->tv_begin.tv_nsec)/1000
diff --git a/osd_receive.cpp b/osd_receive.cpp
index 06e4f7d1..4dbf27f7 100644
--- a/osd_receive.cpp
+++ b/osd_receive.cpp
@@ -140,6 +140,11 @@ void osd_t::handle_finished_read(osd_client_t & cl)
         timespec tv_end;
         clock_gettime(CLOCK_REALTIME, &tv_end);
         subop_stat_count[0][request->req.hdr.opcode]++;
+        if (!subop_stat_count[0][request->req.hdr.opcode])
+        {
+            subop_stat_count[0][request->req.hdr.opcode]++;
+            subop_stat_sum[0][request->req.hdr.opcode] = 0;
+        }
         subop_stat_sum[0][request->req.hdr.opcode] += (
             (tv_end.tv_sec - request->tv_begin.tv_sec)*1000000 +
             (tv_end.tv_nsec - request->tv_begin.tv_nsec)/1000
@@ -252,6 +257,11 @@ void osd_t::handle_reply_hdr(osd_client_t *cl)
         timespec tv_end;
         clock_gettime(CLOCK_REALTIME, &tv_end);
         subop_stat_count[0][op->req.hdr.opcode]++;
+        if (!subop_stat_count[0][op->req.hdr.opcode])
+        {
+            subop_stat_count[0][op->req.hdr.opcode]++;
+            subop_stat_sum[0][op->req.hdr.opcode] = 0;
+        }
         subop_stat_sum[0][op->req.hdr.opcode] += (
             (tv_end.tv_sec - op->tv_begin.tv_sec)*1000000 +
             (tv_end.tv_nsec - op->tv_begin.tv_nsec)/1000
diff --git a/osd_send.cpp b/osd_send.cpp
index 82eeda57..f8decb78 100644
--- a/osd_send.cpp
+++ b/osd_send.cpp
@@ -40,6 +40,12 @@ bool osd_t::try_send(osd_client_t & cl)
             // Measure execution latency
             timespec tv_end = cl.write_op->tv_send;
             op_stat_count[0][cl.write_op->req.hdr.opcode]++;
+            if (!op_stat_count[0][cl.write_op->req.hdr.opcode])
+            {
+                op_stat_count[0][cl.write_op->req.hdr.opcode]++;
+                op_stat_sum[0][cl.write_op->req.hdr.opcode] = 0;
+                op_stat_bytes[0][cl.write_op->req.hdr.opcode] = 0;
+            }
             op_stat_sum[0][cl.write_op->req.hdr.opcode] += (
                 (tv_end.tv_sec - cl.write_op->tv_begin.tv_sec)*1000000 +
                 (tv_end.tv_nsec - cl.write_op->tv_begin.tv_nsec)/1000