rabbitmq · acogoluegnes · Jul 4, 2025 · Sep 9, 2025 · Sep 12, 2025 · Sep 15, 2025
diff --git a/deps/rabbit/Makefile b/deps/rabbit/Makefile
@@ -119,6 +119,7 @@ define PROJECT_ENV
       	{dead_letter_worker_consumer_prefetch, 32},
       	{dead_letter_worker_publisher_confirm_timeout, 180000},
 		{vhost_process_reconciliation_run_interval, 30},
+		{stream_read_ahead, true},
 		%% for testing
 		{vhost_process_reconciliation_enabled, true},
 		{license_line, "Licensed under the MPL 2.0. Website: https://rabbitmq.com"}

diff --git a/deps/rabbit/priv/schema/rabbit.schema b/deps/rabbit/priv/schema/rabbit.schema
@@ -2785,6 +2785,9 @@ fun(Conf) ->
     end
 end}.
 
+{mapping, "stream.read_ahead", "rabbit.stream_read_ahead",
+    [{datatype, {enum, [true, false]}}]}.
+
 {mapping, "cluster_tags.$tag", "rabbit.cluster_tags", [
     {datatype, [binary]}
 ]}.

diff --git a/deps/rabbit/src/rabbit_stream_queue.erl b/deps/rabbit/src/rabbit_stream_queue.erl
@@ -51,6 +51,7 @@
 -export([format_osiris_event/2]).
 -export([update_stream_conf/2]).
 -export([readers/1]).
+-export([read_ahead_on/0]).
 
 -export([parse_offset_arg/1,
          filter_spec/1]).
@@ -463,10 +464,11 @@ query_local_pid(#stream_client{stream_id = StreamId} = State) ->
 begin_stream(#stream_client{name = QName,
                             readers = Readers0,
                             local_pid = LocalPid} = State,
-             Tag, Offset, Mode, AckRequired, Filter, Options)
+             Tag, Offset, Mode, AckRequired, Filter, Options0)
   when is_pid(LocalPid) ->
     CounterSpec = {{?MODULE, QName, Tag, self()}, []},
-    {ok, Seg0} = osiris:init_reader(LocalPid, Offset, CounterSpec, Options),
+    Options1 = Options0#{read_ahead => read_ahead_on()},
+    {ok, Seg0} = osiris:init_reader(LocalPid, Offset, CounterSpec, Options1),
     NextOffset = osiris_log:next_offset(Seg0) - 1,
     osiris:register_offset_listener(LocalPid, NextOffset),
     StartOffset = case Offset of
@@ -491,7 +493,7 @@ begin_stream(#stream_client{name = QName,
                    last_consumed_offset = StartOffset,
                    log = Seg0,
                    filter = Filter,
-                   reader_options = Options},
+                   reader_options = Options1},
     {ok, State#stream_client{readers = Readers0#{Tag => Str0}}}.
 
 cancel(_Q, #{consumer_tag := ConsumerTag,
@@ -659,8 +661,8 @@ handle_event(_QName, {stream_local_member_change, Pid},
                                  osiris_log:close(Log0),
                                  CounterSpec = {{?MODULE, QName, self()}, []},
                                  ?LOG_DEBUG("Re-creating Osiris reader for consumer ~tp at offset ~tp "
-                                                  " with options ~tp",
-                                                  [T, Offset, Options]),
+                                            " with options ~tp",
+                                            [T, Offset, Options]),
                                  {ok, Log1} = osiris:init_reader(Pid, Offset, CounterSpec, Options),
                                  NextOffset = osiris_log:next_offset(Log1) - 1,
                                  ?LOG_DEBUG("Registering offset listener at offset ~tp", [NextOffset]),
@@ -1176,7 +1178,7 @@ stream_entries(QName, Name, CTag, LocalPid,
                        credit = Credit} = Str0) ->
     case Credit > 0 of
         true ->
-            case chunk_iterator(Str0, LocalPid) of
+            case chunk_iterator(Str0, LocalPid, undefined) of
                 {ok, Str} ->
                     stream_entries(QName, Name, CTag, LocalPid, Str);
                 {end_of_stream, Str} ->
@@ -1229,7 +1231,7 @@ stream_entries(QName, Name, CTag, LocalPid,
             gen_server:cast(self(), queue_event(QName, {resume_filtering, CTag})),
             {Str0#stream{filtering_paused = true}, lists:reverse(Acc0)};
         end_of_chunk ->
-            case chunk_iterator(Str0, LocalPid) of
+            case chunk_iterator(Str0, LocalPid, Iter0) of
                 {ok, Str} ->
                     stream_entries(QName, Name, CTag, LocalPid, Str, Acc0);
                 {end_of_stream, Str} ->
@@ -1294,8 +1296,8 @@ stream_entries(QName, Name, CTag, LocalPid,
 
 chunk_iterator(#stream{credit = Credit,
                        listening_offset = LOffs,
-                       log = Log0} = Str0, LocalPid) ->
-    case osiris_log:chunk_iterator(Log0, Credit) of
+                       log = Log0} = Str0, LocalPid, PrevIterator) ->
+    case osiris_log:chunk_iterator(Log0, Credit, PrevIterator) of
         {ok, _ChunkHeader, Iter, Log} ->
             {ok, Str0#stream{chunk_iterator = Iter,
                              log = Log}};
@@ -1527,3 +1529,6 @@ queue_vm_stats_sups() ->
 queue_vm_ets() ->
     {[],
      []}.
+
+read_ahead_on() ->
+    application:get_env(rabbit, stream_read_ahead, true).
diff --git a/deps/rabbit/test/config_schema_SUITE_data/rabbit.snippets b/deps/rabbit/test/config_schema_SUITE_data/rabbit.snippets
@@ -1223,6 +1223,28 @@ credential_validator.regexp = ^abc\\d+",
    [{osiris, [
       {port_range, {4100, 4600}}
      ]}],
+   []},
+
+  %%
+  %% Stream read ahead on/off
+  %%
+
+  {stream_read_ahead,
+   "
+    stream.read_ahead = true
+   ",
+   [{rabbit, [
+      {stream_read_ahead, true}
+     ]}],
+   []},
+
+  {stream_read_ahead,
+   "
+    stream.read_ahead = false
+   ",
+   [{rabbit, [
+      {stream_read_ahead, false}
+     ]}],
    []}
 
 ].
diff --git a/deps/rabbitmq_stream/src/rabbit_stream_reader.erl b/deps/rabbitmq_stream/src/rabbit_stream_reader.erl
@@ -2812,11 +2812,14 @@ init_reader(ConnectionTransport,
             Properties,
             OffsetSpec) ->
     CounterSpec = {{?MODULE, QueueResource, SubscriptionId, self()}, []},
-    Options = maps:merge(#{transport => ConnectionTransport,
-                           chunk_selector => get_chunk_selector(Properties)},
-                         rabbit_stream_utils:filter_spec(Properties)),
-    {ok, Segment} =
-        osiris:init_reader(LocalMemberPid, OffsetSpec, CounterSpec, Options),
+    Options0 = #{transport => ConnectionTransport,
+                 chunk_selector => get_chunk_selector(Properties),
+                 read_ahead => rabbit_stream_queue:read_ahead_on()},
+
+    Options1 = maps:merge(Options0,
+                          rabbit_stream_utils:filter_spec(Properties)),
+    {ok, Segment} = osiris:init_reader(LocalMemberPid, OffsetSpec,
+                                       CounterSpec, Options1),
     ?LOG_DEBUG("Next offset for subscription ~tp is ~tp",
                      [SubscriptionId, osiris_log:next_offset(Segment)]),
     Segment.
@@ -3571,12 +3574,9 @@ subscription_exists(StreamSubscriptions, SubscriptionId) ->
     lists:any(fun(Id) -> Id =:= SubscriptionId end, SubscriptionIds).
 
 send_file_callback(?VERSION_1,
-                   Transport,
                    _Log,
                    #consumer{configuration =
-                                 #consumer_configuration{socket = S,
-                                                         subscription_id =
-                                                             SubscriptionId,
+                                 #consumer_configuration{subscription_id = SubId,
                                                          counters = Counters}},
                    Counter) ->
     fun(#{chunk_id := FirstOffsetInChunk, num_entries := NumEntries},
@@ -3587,19 +3587,16 @@ send_file_callback(?VERSION_1,
              ?REQUEST:1,
              ?COMMAND_DELIVER:15,
              ?VERSION_1:16,
-             SubscriptionId:8/unsigned>>,
-       Transport:send(S, FrameBeginning),
+             SubId:8/unsigned>>,
        atomics:add(Counter, 1, Size),
        increase_messages_consumed(Counters, NumEntries),
-       set_consumer_offset(Counters, FirstOffsetInChunk)
+       set_consumer_offset(Counters, FirstOffsetInChunk),
+       FrameBeginning
     end;
 send_file_callback(?VERSION_2,
-                   Transport,
                    Log,
                    #consumer{configuration =
-                                 #consumer_configuration{socket = S,
-                                                         subscription_id =
-                                                             SubscriptionId,
+                                 #consumer_configuration{subscription_id = SubId,
                                                          counters = Counters}},
                    Counter) ->
     fun(#{chunk_id := FirstOffsetInChunk, num_entries := NumEntries},
@@ -3611,12 +3608,12 @@ send_file_callback(?VERSION_2,
              ?REQUEST:1,
              ?COMMAND_DELIVER:15,
              ?VERSION_2:16,
-             SubscriptionId:8/unsigned,
+             SubId:8/unsigned,
              CommittedChunkId:64>>,
-       Transport:send(S, FrameBeginning),
        atomics:add(Counter, 1, Size),
        increase_messages_consumed(Counters, NumEntries),
-       set_consumer_offset(Counters, FirstOffsetInChunk)
+       set_consumer_offset(Counters, FirstOffsetInChunk),
+       FrameBeginning
     end.
 
 send_chunks(DeliverVersion,
@@ -3686,9 +3683,7 @@ send_chunks(DeliverVersion,
             Retry,
             Counter) ->
     case osiris_log:send_file(Socket, Log,
-                              send_file_callback(DeliverVersion,
-                                                 Transport,
-                                                 Log,
+                              send_file_callback(DeliverVersion, Log,
                                                  Consumer,
                                                  Counter))
     of

diff --git a/deps/rabbitmq_stream/test/rabbit_stream_SUITE.erl b/deps/rabbitmq_stream/test/rabbit_stream_SUITE.erl
@@ -19,6 +19,7 @@
 
 -include_lib("eunit/include/eunit.hrl").
 -include_lib("rabbit_common/include/rabbit.hrl").
+-include_lib("amqp10_common/include/amqp10_framing.hrl").
 -include_lib("rabbitmq_ct_helpers/include/rabbit_assert.hrl").
 -include_lib("rabbitmq_stream_common/include/rabbit_stream.hrl").
 
@@ -1773,3 +1774,9 @@ request(CorrId, Cmd) ->
 
 rand_bin() ->
     base64:encode(rand:bytes(20)).
+
+generate_log(MsgSize, MsgsPerChunk, NumMessages, Directory) ->
+    Body = binary:copy(<<"a">>, MsgSize),
+    Data = #'v1_0.data'{content = Body},
+    Bin = amqp10_framing:encode_bin(Data),
+    osiris_log:generate_log(Bin, MsgsPerChunk, NumMessages, Directory).
diff --git a/rabbitmq-components.mk b/rabbitmq-components.mk
@@ -49,7 +49,7 @@ dep_jose = hex 1.11.10
 dep_khepri = hex 0.17.2
 dep_khepri_mnesia_migration = hex 0.8.0
 dep_meck = hex 1.0.0
-dep_osiris = git https://github.com/rabbitmq/osiris v1.9.0
+dep_osiris = git https://github.com/rabbitmq/osiris send-file-improvements
 dep_prometheus = hex 5.1.1
 dep_ra = hex 2.17.1
 dep_ranch = hex 2.2.0