Re: [Tarantool-patches] [PATCH] net.box: drop conn:timeout()

[Vladimir Davydov via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

On Tue, Jul 27, 2021 at 12:37:17AM +0200, Vladislav Shpilevoy wrote:
> See 5 comments below.

All fixed, thanks. The patch is below:

https://github.com/tarantool/tarantool/tree/vdavydov/net-box-drop-conn-timeout

From f1dbd33e4ccbc586d12460b9061c4c6a30b95f32 Mon Sep 17 00:00:00 2001
From: Vladimir Davydov <vdavydov@tarantool.org>
Date: Mon, 26 Jul 2021 11:59:15 +0300
Subject: [PATCH] net.box: drop conn:timeout()

conn:timeout(timeout) writes (now + timeout) to conn._deadlines table
keyed by fiber.self(). The deadline will then be used by all conn
methods unless specified explicitly in the options argument.

Usage of fiber.self() degrades net.box performance by about 15% in case
timeout is not specified, because it is a C call and so interferes with
JIT. See the ticket for the test details.

Since the feature is unusable and was deprecated more than four years
ago (in 1.7.4) in favor of specifying timeout in the options argument
(see commit 58da206c33197 ("net.box: add { timeout = } option to
requests")), it should be fine to drop it.

Closes #6242

@TarantoolBot document
Title: Delete documentation entry for net.box conn:timeout()

conn:timeout() was deprecated more than four years ago (in 1.7.4). Since
it results in performance degradation in case timeout is not specified
explicitly in request options, we decided to drop it. Please remove it
from the documentation as well:

https://www.tarantool.io/en/doc/latest/reference/reference_lua/net_box/#conn-timeout

diff --git a/changelogs/unreleased/gh-6242-net-box-drop-conn-timeout.md b/changelogs/unreleased/gh-6242-net-box-drop-conn-timeout.md
new file mode 100644
index 000000000000..9571c0afc577
--- /dev/null
+++ b/changelogs/unreleased/gh-6242-net-box-drop-conn-timeout.md
@@ -0,0 +1,9 @@
+## feature/core
+
+* **[Breaking change]** timeout() method of net.box connection, which was
+  marked deprecated more than four years ago (in 1.7.4) was dropped, because
+  it negatively affected performance of hot net.box methods, like call() and
+  select(), in case those are called without specifying a timeout (gh-6242).
+
+---
+Breaking change: timeout() method of net.box connection was dropped.
diff --git a/src/box/lua/net_box.lua b/src/box/lua/net_box.lua
index 3878abf21914..d70927989b71 100644
--- a/src/box/lua/net_box.lua
+++ b/src/box/lua/net_box.lua
@@ -1047,9 +1047,6 @@ local function new_sm(host, port, opts, connection, greeting)
         setmetatable(remote, console_mt)
     else
         setmetatable(remote, remote_mt)
-        -- @deprecated since 1.7.4
-        remote._deadlines = setmetatable({}, {__mode = 'k'})
-
         remote._space_mt = space_metatable(remote)
         remote._index_mt = index_metatable(remote)
         if opts.call_16 then
@@ -1176,17 +1173,11 @@ function remote_methods:_request(method, opts, request_ctx, ...)
             return res
         end
         if opts.timeout then
-            -- conn.space:request(, { timeout = timeout })
             deadline = fiber_clock() + opts.timeout
-        else
-            -- conn:timeout(timeout).space:request()
-            -- @deprecated since 1.7.4
-            deadline = self._deadlines[fiber_self()]
         end
         on_push = opts.on_push or on_push_sync_default
         on_push_ctx = opts.on_push_ctx
     else
-        deadline = self._deadlines[fiber_self()]
         on_push = on_push_sync_default
     end
     -- Execute synchronous request.
@@ -1289,28 +1280,9 @@ end
 
 function remote_methods:wait_state(state, timeout)
     check_remote_arg(self, 'wait_state')
-    if timeout == nil then
-        local deadline = self._deadlines[fiber_self()]
-        timeout = deadline and max(0, deadline - fiber_clock())
-    end
     return self._transport.wait_state(state, timeout)
 end
 
-local compat_warning_said = false
-
--- @deprecated since 1.7.4
-function remote_methods:timeout(timeout)
-    check_remote_arg(self, 'timeout')
-    if not compat_warning_said then
-        compat_warning_said = true
-        log.warn("netbox:timeout(timeout) is deprecated since 1.7.4, "..
-                 "please use space:<request>(..., {timeout = t}) instead.")
-    end
-    -- Sic: this is broken by design
-    self._deadlines[fiber_self()] = (timeout and fiber_clock() + timeout)
-    return self
-end
-
 function remote_methods:_install_schema(schema_version, spaces, indices,
                                         collations)
     local sl, space_mt, index_mt = {}, self._space_mt, self._index_mt
diff --git a/test/box/net.box_count_inconsistent_gh-3262.result b/test/box/net.box_count_inconsistent_gh-3262.result
index c77677625d97..286f9ded8aea 100644
--- a/test/box/net.box_count_inconsistent_gh-3262.result
+++ b/test/box/net.box_count_inconsistent_gh-3262.result
@@ -427,55 +427,6 @@ cn:eval('return ret_after(...)', {1.00}, { timeout = 1e-9 })
 ---
 - error: Timeout exceeded
 ...
---
--- :timeout()
--- @deprecated since 1.7.4
---
-cn:timeout(1).space.net_box_test_space.index.primary:select{234}
----
-- - [234, 1, 2, 3]
-...
-cn:call('ret_after', {.01})
----
-- [[0.01]]
-...
-cn:timeout(1):call('ret_after', {.01})
----
-- [[0.01]]
-...
-cn:timeout(.01):call('ret_after', {1})
----
-- error: Timeout exceeded
-...
-cn = remote:timeout(0.0000000001):connect(LISTEN.host, LISTEN.service, { user = 'netbox', password = '123' })
----
-...
-cn:close()
----
-...
-cn = remote:timeout(1):connect(LISTEN.host, LISTEN.service, { user = 'netbox', password = '123' })
----
-...
-remote.self:ping()
----
-- true
-...
-remote.self.space.net_box_test_space:select{234}
----
-- - [234, 1, 2, 3]
-...
-remote.self:timeout(123).space.net_box_test_space:select{234}
----
-- - [234, 1, 2, 3]
-...
-remote.self:is_connected()
----
-- true
-...
-remote.self:wait_connected()
----
-- true
-...
 cn:close()
 ---
 ...
diff --git a/test/box/net.box_count_inconsistent_gh-3262.test.lua b/test/box/net.box_count_inconsistent_gh-3262.test.lua
index e84e85cf3829..a6d87cdcc830 100644
--- a/test/box/net.box_count_inconsistent_gh-3262.test.lua
+++ b/test/box/net.box_count_inconsistent_gh-3262.test.lua
@@ -155,26 +155,6 @@ cn:call('ret_after', {1.00}, { timeout = 1e-9 })
 cn:eval('return ret_after(...)', {0.01}, { timeout = 1.00 })
 cn:eval('return ret_after(...)', {1.00}, { timeout = 1e-9 })
 
---
--- :timeout()
--- @deprecated since 1.7.4
---
-
-cn:timeout(1).space.net_box_test_space.index.primary:select{234}
-cn:call('ret_after', {.01})
-cn:timeout(1):call('ret_after', {.01})
-cn:timeout(.01):call('ret_after', {1})
-
-cn = remote:timeout(0.0000000001):connect(LISTEN.host, LISTEN.service, { user = 'netbox', password = '123' })
-cn:close()
-cn = remote:timeout(1):connect(LISTEN.host, LISTEN.service, { user = 'netbox', password = '123' })
-
-remote.self:ping()
-remote.self.space.net_box_test_space:select{234}
-remote.self:timeout(123).space.net_box_test_space:select{234}
-remote.self:is_connected()
-remote.self:wait_connected()
-
 cn:close()
 -- cleanup database after tests
 space:drop()