diff --git a/mod/box/box.lua b/mod/box/box.lua
index 10d395c3e8f1331ca91c69c09c4aa3db40204d03..96f4f0a83077af8e431b9a00c57455768bf811e3 100644
--- a/mod/box/box.lua
+++ b/mod/box/box.lua
@@ -253,12 +253,19 @@ function box.on_reload_configuration()
index_mt.max = function(index) return index.idx:max() end
-- iteration
index_mt.pairs = function(index)
- return index.idx.next, index.idx, nil end
+ return index.idx.next, index.idx, nil
+ end
--
index_mt.next = function(index, ...)
- return index.idx:next(...) end
+ return index.idx:next(...)
+ end
index_mt.prev = function(index, ...)
- return index.idx:prev(...) end
+ return index.idx:prev(...)
+ end
+ -- index subtree size
+ index_mt.count = function(index, ...)
+ return index.idx:count(...)
+ end
--
index_mt.select_range = function(index, limit, ...)
local range = {}
diff --git a/mod/box/box_lua.m b/mod/box/box_lua.m
index 6dcf1458a3efc96503e806d5cd9461abf5462e92..98301087e52426371511a40d5857ca4009881c24 100644
--- a/mod/box/box_lua.m
+++ b/mod/box/box_lua.m
@@ -562,6 +562,50 @@ lbox_index_prev_equal(struct lua_State *L)
return tuple ? 2 : 1;
}
+/**
+ * Lua index subtree count function.
+ * Function iterates over an index, counting
+ * number of tuples which equals key search criteria.
+ * Key can be multi-parted.
+ */
+static int
+lbox_index_count(struct lua_State *L)
+{
+ Index *index = lua_checkindex(L, 1);
+ int argc = lua_gettop(L) - 1;
+ /* preparing single or multi-part key */
+ void *key;
+ int key_part_count;
+ if (argc == 1 && lua_type(L, 2) == LUA_TUSERDATA) {
+ /* Searching by tuple. */
+ struct tuple *tuple = lua_checktuple(L, 2);
+ key = tuple->data;
+ key_part_count = tuple->field_count;
+ } else {
+ /* Single or multi- part key. */
+ key_part_count = argc;
+ struct tbuf *data = tbuf_alloc(fiber->gc_pool);
+ for (int i = 0; i < argc; ++i)
+ append_key_part(L, i + 2, data,
+ index->key_def->parts[i].type);
+ key = data->data;
+ }
+ u32 count = 0;
+ /* preparing index iterator */
+ struct iterator *it = index->position;
+ [index initIteratorByKey: it :ITER_FORWARD :key :key_part_count];
+ /* iterating over the index and counting tuples */
+ struct tuple *tuple;
+ while ((tuple = it->next_equal(it)) != NULL) {
+ if (tuple->flags & GHOST)
+ continue;
+ count++;
+ }
+ /* returning subtree size */
+ lua_pushnumber(L, count);
+ return 1;
+}
+
static const struct luaL_reg lbox_index_meta[] = {
{"__tostring", lbox_index_tostring},
{"__len", lbox_index_len},
@@ -572,6 +616,7 @@ static const struct luaL_reg lbox_index_meta[] = {
{"prev", lbox_index_prev},
{"next_equal", lbox_index_next_equal},
{"prev_equal", lbox_index_prev_equal},
+ {"count", lbox_index_count},
{NULL, NULL}
};
diff --git a/test/box_big/lua.result b/test/box_big/lua.result
index 2cc668b07f6f3862cbc5e9eea049b47c11b95f8b..fbd794dec5fce8c7c286512f4594976d6b8062fb 100644
--- a/test/box_big/lua.result
+++ b/test/box_big/lua.result
@@ -258,3 +258,55 @@ lua for k, v in box.space[16].index[1].idx.prev_equal, box.space[16].index[1].id
'pid_5': {'sid_2', 'tid_995'}
'pid_6': {'sid_2', 'tid_994'}
...
+lua box.insert(17, 1, 1, 1)
+---
+ - 1: {1, 1}
+...
+lua box.insert(17, 2, 2, 0)
+---
+ - 2: {2, 0}
+...
+lua box.insert(17, 3, 2, 1)
+---
+ - 3: {2, 1}
+...
+lua box.insert(17, 4, 3, 0)
+---
+ - 4: {3, 0}
+...
+lua box.insert(17, 5, 3, 1)
+---
+ - 5: {3, 1}
+...
+lua box.insert(17, 6, 3, 2)
+---
+ - 6: {3, 2}
+...
+lua box.space[17].index[1].idx:count(1)
+---
+ - 1
+...
+lua box.space[17].index[1].idx:count(2)
+---
+ - 2
+...
+lua box.space[17].index[1].idx:count(2, 1)
+---
+ - 1
+...
+lua box.space[17].index[1].idx:count(2, 2)
+---
+ - 0
+...
+lua box.space[17].index[1].idx:count(3)
+---
+ - 3
+...
+lua box.space[17].index[1].idx:count(3, 3)
+---
+ - 0
+...
+lua box.space[17].index[1].idx:count()
+---
+ - 6
+...
diff --git a/test/box_big/lua.test b/test/box_big/lua.test
index 019549a4d9cfb16cc7036e3297cb6f8846d59bf5..4e6de1151bf38f21594c54ed6d18081ee7fd6418 100644
--- a/test/box_big/lua.test
+++ b/test/box_big/lua.test
@@ -89,3 +89,20 @@ exec admin "lua for k, v in box.space[16].index[1].idx.next_equal, box.space[16]
exec admin "lua for k, v in box.space[16].index[1].idx.prev_equal, box.space[16].index[1].idx, 'sid_1' do print(v) end"
exec admin "lua for k, v in box.space[16].index[1].idx.next_equal, box.space[16].index[1].idx, 'sid_2' do print(v) end"
exec admin "lua for k, v in box.space[16].index[1].idx.prev_equal, box.space[16].index[1].idx, 'sid_2' do print(v) end"
+
+#
+# Tests for lua idx:count()
+#
+exec admin "lua box.insert(17, 1, 1, 1)"
+exec admin "lua box.insert(17, 2, 2, 0)"
+exec admin "lua box.insert(17, 3, 2, 1)"
+exec admin "lua box.insert(17, 4, 3, 0)"
+exec admin "lua box.insert(17, 5, 3, 1)"
+exec admin "lua box.insert(17, 6, 3, 2)"
+exec admin "lua box.space[17].index[1].idx:count(1)"
+exec admin "lua box.space[17].index[1].idx:count(2)"
+exec admin "lua box.space[17].index[1].idx:count(2, 1)"
+exec admin "lua box.space[17].index[1].idx:count(2, 2)"
+exec admin "lua box.space[17].index[1].idx:count(3)"
+exec admin "lua box.space[17].index[1].idx:count(3, 3)"
+exec admin "lua box.space[17].index[1].idx:count()"
diff --git a/test/box_big/tarantool.cfg b/test/box_big/tarantool.cfg
index 22a8974f230645c54afe0491fa37688da7618aad..90748b5d5193f65b46cc6b20c08963570928c81c 100644
--- a/test/box_big/tarantool.cfg
+++ b/test/box_big/tarantool.cfg
@@ -212,3 +212,17 @@ space[16].index[1].key_field[0].fieldno = 1
space[16].index[1].key_field[0].type = "STR"
space[16].index[1].key_field[1].fieldno = 2
space[16].index[1].key_field[1].type = "STR"
+
+# lua index.idx:count() testing
+# https://blueprints.launchpad.net/tarantool/+spec/lua-builtin-size-of-subtree
+space[17].enabled = true
+space[17].index[0].type = "HASH"
+space[17].index[0].unique = 1
+space[17].index[0].key_field[0].fieldno = 0
+space[17].index[0].key_field[0].type = "NUM"
+space[17].index[1].type = "TREE"
+space[17].index[1].unique = 0
+space[17].index[1].key_field[0].fieldno = 1
+space[17].index[1].key_field[0].type = "NUM"
+space[17].index[1].key_field[1].fieldno = 2
+space[17].index[1].key_field[1].type = "NUM"