[Tarantool-patches] [PATCH] net.box: allow to store user-defined fields in future object
Vladimir Davydov
vdavydov at tarantool.org
Tue Aug 10 19:53:54 MSK 2021
Before commit 954194a1ca5c ("net.box: rewrite request implementation in
C"), net.box future was a plain Lua table so that the caller could
attach extra information to it. Now it isn't true anymore - a future is
a userdata object, and it doesn't have indexing methods.
For backward compatibility, let's add __index and __newindex fields and
store user-defined fields in an mhash, which is created lazily on the
first __newindex invocation. __index falls back on the metatable methods
if a field isn't found in the mhash.
Follow-up #6241
Closes #6306
---
https://github.com/tarantool/tarantool/tree/vdavydov/netbox-allow-to-store-user-data-in-future
https://github.com/tarantool/tarantool/issues/6241
https://github.com/tarantool/tarantool/issues/6306
As a result of this patch, async net.box.call performance degrades by
about 2-3% because of an extra C function call executed per each future
member access:
| KRPS (PROC TIME) | KRPS (WALL TIME)
before | 276 +- 9 | 448 +- 22
after | 270 +- 8 | 434 +- 21
Still, it's better than wrapping a future object into a table, which
degrades performance by 10%.
src/box/lua/net_box.c | 91 ++++++++++++++++
test/box/net.box_fiber-async_gh-3107.result | 103 +++++++++++++++++-
test/box/net.box_fiber-async_gh-3107.test.lua | 37 ++++++-
3 files changed, 223 insertions(+), 8 deletions(-)
diff --git a/src/box/lua/net_box.c b/src/box/lua/net_box.c
index 06e574cdf746..162ff6c82fb0 100644
--- a/src/box/lua/net_box.c
+++ b/src/box/lua/net_box.c
@@ -134,6 +134,14 @@ struct netbox_request {
* the response hasn't been received yet.
*/
struct error *error;
+ /**
+ * User-defined fields: field name -> Lua object reference.
+ * We allow the user to attach extra information to a future object,
+ * e.g. a reference to a connection or the invoked method name/args.
+ * All the information is stored in this table, which is created
+ * lazily, on the first __newindex invocation.
+ */
+ struct mh_strnptr_t *index;
};
static const char netbox_registry_typename[] = "net.box.registry";
@@ -166,6 +174,15 @@ netbox_request_destroy(struct netbox_request *request)
luaL_unref(tarantool_L, LUA_REGISTRYINDEX, request->result_ref);
if (request->error != NULL)
error_unref(request->error);
+ if (request->index != NULL) {
+ struct mh_strnptr_t *h = request->index;
+ mh_int_t k;
+ mh_foreach(h, k) {
+ int ref = (intptr_t)mh_strnptr_node(h, k)->val;
+ luaL_unref(tarantool_L, LUA_REGISTRYINDEX, ref);
+ }
+ mh_strnptr_delete(h);
+ }
}
/**
@@ -1358,6 +1375,77 @@ luaT_netbox_request_gc(struct lua_State *L)
return 0;
}
+static int
+luaT_netbox_request_index(struct lua_State *L)
+{
+ struct netbox_request *request = luaT_check_netbox_request(L, 1);
+ size_t field_name_len;
+ const char *field_name = lua_tolstring(L, 2, &field_name_len);
+ if (field_name == NULL)
+ return luaL_error(L, "invalid index");
+ if (request->index != NULL) {
+ mh_int_t k = mh_strnptr_find_inp(request->index, field_name,
+ field_name_len);
+ if (k != mh_end(request->index)) {
+ int field_value_ref = (intptr_t)mh_strnptr_node(
+ request->index, k)->val;
+ lua_rawgeti(L, LUA_REGISTRYINDEX, field_value_ref);
+ return 1;
+ }
+ }
+ /* Fall back on metatable methods. */
+ return luaL_getmetafield(L, 1, field_name) != LUA_TNIL ? 1 : 0;
+}
+
+static int
+luaT_netbox_request_newindex(struct lua_State *L)
+{
+ struct netbox_request *request = luaT_check_netbox_request(L, 1);
+ struct mh_strnptr_t *h = request->index;
+ size_t field_name_len;
+ const char *field_name = lua_tolstring(L, 2, &field_name_len);
+ if (field_name == NULL)
+ return luaL_error(L, "invalid index");
+ int field_value_ref = luaL_ref(L, LUA_REGISTRYINDEX);
+ if (field_value_ref == LUA_REFNIL) {
+ /* The field is set to nil. Delete it from the index. */
+ if (h == NULL)
+ return 0;
+ mh_int_t k = mh_strnptr_find_inp(h, field_name,
+ field_name_len);
+ int ref = (intptr_t)mh_strnptr_node(h, k)->val;
+ luaL_unref(L, LUA_REGISTRYINDEX, ref);
+ mh_strnptr_del(h, k, NULL);
+ return 0;
+ }
+ if (h == NULL) {
+ /* Lazily create the index on the first invocation. */
+ h = request->index = mh_strnptr_new();
+ if (h == NULL) {
+ luaL_unref(L, LUA_REGISTRYINDEX, field_value_ref);
+ return luaL_error(L, "out of memory");
+ }
+ }
+ /* Insert a reference to the new value into the index. */
+ struct mh_strnptr_node_t node = {
+ .str = field_name,
+ .len = field_name_len,
+ .hash = mh_strn_hash(field_name, field_name_len),
+ .val = (void *)(intptr_t)field_value_ref,
+ };
+ struct mh_strnptr_node_t old_node = { NULL, 0, 0, NULL };
+ struct mh_strnptr_node_t *p_old_node = &old_node;
+ if (mh_strnptr_put(h, &node, &p_old_node,
+ NULL) == mh_end(h)) {
+ luaL_unref(L, LUA_REGISTRYINDEX, field_value_ref);
+ return luaL_error(L, "out of memory");
+ }
+ /* Drop the reference to the overwritten value. */
+ if (p_old_node != NULL)
+ luaL_unref(L, LUA_REGISTRYINDEX, (intptr_t)old_node.val);
+ return 0;
+}
+
/**
* Returns true if the response was received for the given request.
*/
@@ -1602,6 +1690,7 @@ netbox_make_request(struct lua_State *L, int idx,
fiber_cond_create(&request->cond);
request->result_ref = LUA_NOREF;
request->error = NULL;
+ request->index = NULL;
if (netbox_request_register(request, registry) != 0) {
netbox_request_destroy(request);
luaT_error(L);
@@ -1988,6 +2077,8 @@ luaopen_net_box(struct lua_State *L)
static const struct luaL_Reg netbox_request_meta[] = {
{ "__gc", luaT_netbox_request_gc },
+ { "__index", luaT_netbox_request_index },
+ { "__newindex", luaT_netbox_request_newindex },
{ "is_ready", luaT_netbox_request_is_ready },
{ "result", luaT_netbox_request_result },
{ "wait_result", luaT_netbox_request_wait_result },
diff --git a/test/box/net.box_fiber-async_gh-3107.result b/test/box/net.box_fiber-async_gh-3107.result
index aaaca351a579..e44db726c8cb 100644
--- a/test/box/net.box_fiber-async_gh-3107.result
+++ b/test/box/net.box_fiber-async_gh-3107.result
@@ -10,10 +10,7 @@ net = require('net.box')
cond = nil
---
...
-box.schema.func.create('long_function')
----
-...
-box.schema.user.grant('guest', 'execute', 'function', 'long_function')
+box.schema.user.grant('guest', 'execute', 'universe')
---
...
function long_function(...) cond = fiber.cond() cond:wait() return ... end
@@ -104,7 +101,103 @@ err:find('Usage') ~= nil
---
- true
...
-box.schema.func.drop('long_function')
+-- Storing user data in future object.
+future = c:eval('return 123', {}, {is_async = true})
+---
+...
+future.abc -- nil
+---
+- null
+...
+future.abc = 'abc'
+---
+...
+future.abc -- abc
+---
+- abc
+...
+future.abc = nil
+---
+...
+future.abc -- nil
+---
+- null
+...
+future[{}] -- error
+---
+- error: '[string "return future[{}] -- error "]:1: invalid index'
+...
+future[{}] = 'abc' -- error
+---
+- error: '[string "future[{}] = ''abc'' -- error "]:1: invalid index'
+...
+future:wait_result() -- 123
+---
+- [123]
+...
+-- Garbage collection of stored user data.
+future = c:eval('return 123', {}, {is_async = true})
+---
+...
+future.data1 = {1}
+---
+...
+future.data2 = {2}
+---
+...
+future.data3 = {3}
+---
+...
+gc = setmetatable({}, {__mode = 'v'})
+---
+...
+gc.data1 = future.data1
+---
+...
+gc.data2 = future.data2
+---
+...
+gc.data3 = future.data3
+---
+...
+future.data1 = nil
+---
+...
+_ = collectgarbage('collect')
+---
+...
+gc.data1 == nil
+---
+- true
+...
+future.data2 = 123
+---
+...
+_ = collectgarbage('collect')
+---
+...
+gc.data2 == nil
+---
+- true
+...
+future:wait_result() -- 123
+---
+- [123]
+...
+future = nil
+---
+...
+_ = collectgarbage('collect')
+---
+...
+_ = collectgarbage('collect')
+---
+...
+gc.data3 == nil
+---
+- true
+...
+box.schema.user.revoke('guest', 'execute', 'universe')
---
...
c:close()
diff --git a/test/box/net.box_fiber-async_gh-3107.test.lua b/test/box/net.box_fiber-async_gh-3107.test.lua
index d23f368cbce4..5571aeb935e0 100644
--- a/test/box/net.box_fiber-async_gh-3107.test.lua
+++ b/test/box/net.box_fiber-async_gh-3107.test.lua
@@ -5,8 +5,7 @@ net = require('net.box')
-- gh-3107: fiber-async netbox.
--
cond = nil
-box.schema.func.create('long_function')
-box.schema.user.grant('guest', 'execute', 'function', 'long_function')
+box.schema.user.grant('guest', 'execute', 'universe')
function long_function(...) cond = fiber.cond() cond:wait() return ... end
function finalize_long() while not cond do fiber.sleep(0.01) end cond:signal() cond = nil end
s = box.schema.create_space('test')
@@ -36,7 +35,39 @@ err:find('Usage') ~= nil
_, err = pcall(future.wait_result, future, '100')
err:find('Usage') ~= nil
-box.schema.func.drop('long_function')
+-- Storing user data in future object.
+future = c:eval('return 123', {}, {is_async = true})
+future.abc -- nil
+future.abc = 'abc'
+future.abc -- abc
+future.abc = nil
+future.abc -- nil
+future[{}] -- error
+future[{}] = 'abc' -- error
+future:wait_result() -- 123
+
+-- Garbage collection of stored user data.
+future = c:eval('return 123', {}, {is_async = true})
+future.data1 = {1}
+future.data2 = {2}
+future.data3 = {3}
+gc = setmetatable({}, {__mode = 'v'})
+gc.data1 = future.data1
+gc.data2 = future.data2
+gc.data3 = future.data3
+future.data1 = nil
+_ = collectgarbage('collect')
+gc.data1 == nil
+future.data2 = 123
+_ = collectgarbage('collect')
+gc.data2 == nil
+future:wait_result() -- 123
+future = nil
+_ = collectgarbage('collect')
+_ = collectgarbage('collect')
+gc.data3 == nil
+
+box.schema.user.revoke('guest', 'execute', 'universe')
c:close()
s:drop()
--
2.25.1
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