diff --git a/ldap/servers/slapd/back-ldbm/ldbm_search.c b/ldap/servers/slapd/back-ldbm/ldbm_search.c
index 5c39c9ac2a..ef4b7c4cc6 100644
--- a/ldap/servers/slapd/back-ldbm/ldbm_search.c
+++ b/ldap/servers/slapd/back-ldbm/ldbm_search.c
@@ -35,6 +35,7 @@ static IDList *onelevel_candidates(Slapi_PBlock *pb, backend *be, const char *ba
 static back_search_result_set *new_search_result_set(IDList *idl, int vlv, int lookthroughlimit);
 static void delete_search_result_set(Slapi_PBlock *pb, back_search_result_set **sr);
 static int can_skip_filter_test(Slapi_PBlock *pb, struct slapi_filter *f, int scope, IDList *idl);
+static void stat_add_srch_lookup(Op_stat *op_stat, char * attribute_type, const char* index_type, char *key_value, int lookup_cnt);
 
 /* This is for performance testing, allows us to disable ACL checking altogether */
 #if defined(DISABLE_ACL_CHECK)
@@ -1197,6 +1198,45 @@ create_subtree_filter(Slapi_Filter *filter, int managedsait)
     return ftop;
 }
 
+static void
+stat_add_srch_lookup(Op_stat *op_stat, char * attribute_type, const char* index_type, char *key_value, int lookup_cnt)
+{
+    struct component_keys_lookup *key_stat;
+
+    if ((op_stat == NULL) || (op_stat->search_stat == NULL)) {
+        return;
+    }
+
+    /* gather the index lookup statistics */
+    key_stat = (struct component_keys_lookup *) slapi_ch_calloc(1, sizeof (struct component_keys_lookup));
+
+    /* indextype is "eq" */
+    if (index_type) {
+        key_stat->index_type = slapi_ch_strdup(index_type);
+    }
+
+    /* key value e.g. '1234' */
+    if (key_value) {
+        key_stat->key = (char *) slapi_ch_calloc(1, strlen(key_value) + 1);
+        memcpy(key_stat->key, key_value, strlen(key_value));
+    }
+
+    /* attribute name is e.g. 'uid' */
+    if (attribute_type) {
+        key_stat->attribute_type = slapi_ch_strdup(attribute_type);
+    }
+
+    /* Number of lookup IDs with the key */
+    key_stat->id_lookup_cnt = lookup_cnt;
+    if (op_stat->search_stat->keys_lookup) {
+        /* it already exist key stat. add key_stat at the head */
+        key_stat->next = op_stat->search_stat->keys_lookup;
+    } else {
+        /* this is the first key stat record */
+        key_stat->next = NULL;
+    }
+    op_stat->search_stat->keys_lookup = key_stat;
+}
 
 /*
  * Build a candidate list for a SUBTREE scope search.
@@ -1245,6 +1285,17 @@ subtree_candidates(
     if (candidates != NULL && (idl_length(candidates) > FILTER_TEST_THRESHOLD) && e) {
         IDList *tmp = candidates, *descendants = NULL;
         back_txn txn = {NULL};
+        Op_stat *op_stat = NULL;
+        char key_value[32] = {0};
+
+        /* statistics for index lookup is enabled */
+        if (LDAP_STAT_READ_INDEX & config_get_statlog_level()) {
+            op_stat = op_stat_get_operation_extension(pb);
+            if (op_stat) {
+                /* easier to just record the entry ID */
+                PR_snprintf(key_value, sizeof(key_value), "%lu", (u_long) e->ep_id);
+            }
+        }
 
         slapi_pblock_get(pb, SLAPI_TXN, &txn.back_txn_txn);
         if (entryrdn_get_noancestorid()) {
@@ -1252,12 +1303,20 @@ subtree_candidates(
             *err = entryrdn_get_subordinates(be,
                                              slapi_entry_get_sdn_const(e->ep_entry),
                                              e->ep_id, &descendants, &txn, 0);
+            if (op_stat) {
+                /* record entryrdn lookups */
+                stat_add_srch_lookup(op_stat, LDBM_ENTRYRDN_STR, indextype_EQUALITY, key_value, descendants ? descendants->b_nids : 0);
+            }
             idl_insert(&descendants, e->ep_id);
             candidates = idl_intersection(be, candidates, descendants);
             idl_free(&tmp);
             idl_free(&descendants);
         } else if (!has_tombstone_filter && !is_bulk_import) {
             *err = ldbm_ancestorid_read_ext(be, &txn, e->ep_id, &descendants, allidslimit);
+            if (op_stat) {
+                /* records ancestorid lookups */
+                stat_add_srch_lookup(op_stat, LDBM_ANCESTORID_STR, indextype_EQUALITY, key_value, descendants ? descendants->b_nids : 0);
+            }
             idl_insert(&descendants, e->ep_id);
             candidates = idl_intersection(be, candidates, descendants);
             idl_free(&tmp);