File 4411-Replace-some-uses-of-ets-lookup-by-ets-lookup_elemen.patch of Package erlang
From 8134a8078433d46acb4e20df98ec7939845567e3 Mon Sep 17 00:00:00 2001
From: Robin Morisset <rmorisset@fb.com>
Date: Tue, 11 Oct 2022 15:45:15 +0200
Subject: [PATCH] Replace some uses of ets:lookup by ets:lookup_element in the
stdlib
When only one field of an ETS record is needed, using ets:lookup_element is usually faster than ets:lookup.
This patch makes sure that we do so whenever possible, taking advantage of the recently landed
ets:lookup_element/4 (https://github.com/erlang/otp/pull/6234) in places.
---
lib/asn1/src/asn1_db.erl | 11 ++++-------
lib/kernel/src/application.erl | 9 ++-------
lib/kernel/src/application_controller.erl | 17 +++++++++--------
lib/kernel/src/inet_db.erl | 4 +---
lib/kernel/src/pg.erl | 14 ++------------
lib/stdlib/src/beam_lib.erl | 3 +--
6 files changed, 19 insertions(+), 39 deletions(-)
diff --git a/lib/asn1/src/asn1_db.erl b/lib/asn1/src/asn1_db.erl
index 7486fa2db9..28c1fc4563 100644
--- a/lib/asn1/src/asn1_db.erl
+++ b/lib/asn1/src/asn1_db.erl
@@ -82,11 +82,11 @@ loop(#state{parent = Parent, monitor = MRef, table = Table,
includes = Includes} = State) ->
receive
{set, Mod, K2, V} ->
- [{_, Modtab}] = ets:lookup(Table, Mod),
+ Modtab = ets:lookup_element(Table, Mod, 2),
ets:insert(Modtab, {K2, V}),
loop(State);
{set, Mod, Kvs} ->
- [{_, Modtab}] = ets:lookup(Table, Mod),
+ Modtab = ets:lookup_element(Table, Mod, 2),
ets:insert(Modtab, Kvs),
loop(State);
{From, {get, Mod, K2}} ->
@@ -105,7 +105,7 @@ loop(#state{parent = Parent, monitor = MRef, table = Table,
end,
loop(State);
{save, OutFile, Mod} ->
- [{_,Mtab}] = ets:lookup(Table, Mod),
+ Mtab = ets:lookup_element(Table, Mod, 2),
TempFile = OutFile ++ ".#temp",
ok = ets:tab2file(Mtab, TempFile),
ok = file:rename(TempFile, OutFile),
@@ -146,10 +146,7 @@ get_table(Table, Mod, Includes) ->
end.
lookup(Tab, K) ->
- case ets:lookup(Tab, K) of
- [] -> undefined;
- [{K,V}] -> V
- end.
+ ets:lookup_element(Tab, K, 2, undefined).
info(EruleMaps) ->
{asn1ct:vsn(),EruleMaps}.
diff --git a/lib/kernel/src/application.erl b/lib/kernel/src/application.erl
index 3eb87d73c7..1730e1e822 100644
--- a/lib/kernel/src/application.erl
+++ b/lib/kernel/src/application.erl
@@ -397,13 +397,8 @@ get_env(Application, Key) ->
Def :: term(),
Val :: term().
-get_env(Application, Key, Def) ->
- case get_env(Application, Key) of
- {ok, Val} ->
- Val;
- undefined ->
- Def
- end.
+get_env(Application, Key, Default) ->
+ application_controller:get_env(Application, Key, Default).
-spec get_all_env() -> Env when
Env :: [{Par :: atom(), Val :: term()}].
diff --git a/lib/kernel/src/application_controller.erl b/lib/kernel/src/application_controller.erl
index b82c3b0784..c5b4445bb8 100644
--- a/lib/kernel/src/application_controller.erl
+++ b/lib/kernel/src/application_controller.erl
@@ -27,7 +27,7 @@
change_application_data/2, prep_config_change/0, config_change/1,
which_applications/0, which_applications/1,
loaded_applications/0, info/0, set_env/2,
- get_pid_env/2, get_env/2, get_pid_all_env/1, get_all_env/1,
+ get_pid_env/2, get_env/2, get_env/3, get_pid_all_env/1, get_all_env/1,
get_pid_key/2, get_key/2, get_pid_all_key/1, get_all_key/1,
get_master/1, get_application/1, get_application_module/1,
start_type/1, permit_application/2, do_config_diff/2,
@@ -343,11 +343,15 @@ get_pid_env(Master, Key) ->
end.
get_env(AppName, Key) ->
- case ets:lookup(ac_tab, {env, AppName, Key}) of
- [{_, Val}] -> {ok, Val};
- _ -> undefined
+ NotFound = make_ref(),
+ case ets:lookup_element(ac_tab, {env, AppName, Key}, 2, NotFound) of
+ NotFound -> undefined;
+ Val -> {ok, Val}
end.
+get_env(AppName, Key, Default) ->
+ ets:lookup_element(ac_tab, {env, AppName, Key}, 2, Default).
+
get_pid_all_env(Master) ->
case ets:match(ac_tab, {{application_master, '$1'}, Master}) of
[[AppName]] -> get_all_env(AppName);
@@ -442,10 +446,7 @@ start_type(Master) ->
get_master(AppName) ->
- case ets:lookup(ac_tab, {application_master, AppName}) of
- [{_, Pid}] -> Pid;
- _ -> undefined
- end.
+ ets:lookup_element(ac_tab, {application_master, AppName}, 2, undefined).
get_application(Master) ->
case ets:match(ac_tab, {{application_master, '$1'}, Master}) of
diff --git a/lib/kernel/src/inet_db.erl b/lib/kernel/src/inet_db.erl
index 408f563909..4937bc0751 100644
--- a/lib/kernel/src/inet_db.erl
+++ b/lib/kernel/src/inet_db.erl
@@ -579,9 +579,7 @@ res_update(Option, TagTm) ->
end.
db_get(Name) ->
- try ets:lookup_element(inet_db, Name, 2)
- catch error:badarg -> undefined
- end.
+ ets:lookup_element(inet_db, Name, 2, undefined).
add_rr(RR) ->
%% Questionable if we need to support this;
diff --git a/lib/kernel/src/pg.erl b/lib/kernel/src/pg.erl
index 017b1942b4..94c9772468 100644
--- a/lib/kernel/src/pg.erl
+++ b/lib/kernel/src/pg.erl
@@ -203,12 +203,7 @@ get_members(Group) ->
-spec get_members(Scope :: atom(), Group :: group()) -> [pid()].
get_members(Scope, Group) ->
- try
- ets:lookup_element(Scope, Group, 2)
- catch
- error:badarg ->
- []
- end.
+ ets:lookup_element(Scope, Group, 2, []).
%%--------------------------------------------------------------------
%% @doc
@@ -219,12 +214,7 @@ get_local_members(Group) ->
-spec get_local_members(Scope :: atom(), Group :: group()) -> [pid()].
get_local_members(Scope, Group) ->
- try
- ets:lookup_element(Scope, Group, 3)
- catch
- error:badarg ->
- []
- end.
+ ets:lookup_element(Scope, Group, 3, []).
%%--------------------------------------------------------------------
%% @doc
diff --git a/lib/stdlib/src/beam_lib.erl b/lib/stdlib/src/beam_lib.erl
index 0753fbbd2b..b5249df414 100644
--- a/lib/stdlib/src/beam_lib.erl
+++ b/lib/stdlib/src/beam_lib.erl
@@ -832,8 +832,7 @@ symbol(_, AT, I1, I2, _I3, _Cnt) ->
{atm(AT, I1), I2}.
atm(AT, N) ->
- [{_N, S}] = ets:lookup(AT, N),
- S.
+ ets:lookup_element(AT, N, 2).
%% AT is updated.
ensure_atoms({empty, AT}, Cs) ->
--
2.35.3
