Reduce distance to default, add a tiny bit more explanation.

2 files changed, 10 insertions, 16 deletions

diff --git a/src/rabbit_queue_index.erl b/src/rabbit_queue_index.erl
index 75b13e02..fa751d0c 100644
--- a/src/rabbit_queue_index.erl
+++ b/src/rabbit_queue_index.erl
@@ -889,16 +889,6 @@ write_entry_to_segment(RelSeq, {Pub, Del, Ack}, Hdl) ->
              no_pub ->
                  ok;
              {MsgOrId, MsgProps, IsPersistent} ->
-                 %% Body = create_pub_record_body(MsgOrId, MsgProps),
-                 %% io:format("pub ~p~n",
-                 %%           [[{persist, IsPersistent},
-                 %%                         {relseq, RelSeq},
-                 %%                         {body, Body}]]),
-                 %% io:format("write ~p~n",
-                 %%           [iolist_to_binary([<<?PUB_PREFIX:?PUB_PREFIX_BITS,
-                 %%                                (bool_to_int(IsPersistent)):1,
-                 %%                                RelSeq:?REL_SEQ_BITS>>,
-                 %%                              Body])]),
                  file_handle_cache:append(
                    Hdl, [<<?PUB_PREFIX:?PUB_PREFIX_BITS,
                            (bool_to_int(IsPersistent)):1,
diff --git a/src/rabbit_variable_queue.erl b/src/rabbit_variable_queue.erl
index 9711673c..094db17f 100644
--- a/src/rabbit_variable_queue.erl
+++ b/src/rabbit_variable_queue.erl
@@ -32,11 +32,11 @@
 
 %%----------------------------------------------------------------------------
 %% Definitions:
-
+%%
 %% alpha: this is a message where both the message itself, and its
 %%        position within the queue are held in RAM
 %%
-%% beta: this is a message where the message itself is only held on
+%% beta:  this is a message where the message itself is only held on
 %%        disk, but its position within the queue is held in RAM.
 %%
 %% gamma: this is a message where the message itself is only held on
@@ -54,6 +54,11 @@
 %% appears. It's frequently the case that gammas are defined by betas
 %% who have had their queue position recorded on disk.
 %%
+%% Furthermore note that for small messages we can persist the message
+%% to the queue index rather than the message store; if this happens
+%% then the message will still be in memory when the message is a
+%% beta.
+%%
 %% In general, messages move q1 -> q2 -> delta -> q3 -> q4, though
 %% many of these steps are frequently skipped. q1 and q4 only hold
 %% alphas, q2 and q3 hold both betas and gammas. When a message
@@ -1669,8 +1674,7 @@ next({delta, #delta{start_seq_id = SeqId,
                     end_seq_id   = SeqIdEnd} = Delta, State}, IndexState) ->
     SeqIdB = rabbit_queue_index:next_segment_boundary(SeqId),
     SeqId1 = lists:min([SeqIdB, SeqIdEnd]),
-    {List, IndexState1} =
-        rabbit_queue_index:read(SeqId, SeqId1, IndexState),
+    {List, IndexState1} = rabbit_queue_index:read(SeqId, SeqId1, IndexState),
     next({delta, Delta#delta{start_seq_id = SeqId1}, List, State}, IndexState1);
 next({delta, Delta, [], State}, IndexState) ->
     next({delta, Delta, State}, IndexState);
@@ -1852,8 +1856,8 @@ maybe_deltas_to_betas(State = #vqstate {
     DeltaSeqId1 =
         lists:min([rabbit_queue_index:next_segment_boundary(DeltaSeqId),
                    DeltaSeqIdEnd]),
-    {List, IndexState1} =
-        rabbit_queue_index:read(DeltaSeqId, DeltaSeqId1, IndexState),
+    {List, IndexState1} = rabbit_queue_index:read(DeltaSeqId, DeltaSeqId1,
+                                                  IndexState),
     {Q3a, RamCountsInc, RamBytesInc, IndexState2} =
         betas_from_index_entries(List, TransientThreshold,
                                  RPA, DPA, QPA, IndexState1),