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authorRob Harrop <rob@rabbitmq.com>2010-11-05 09:18:05 +0000
committerRob Harrop <rob@rabbitmq.com>2010-11-05 09:18:05 +0000
commit8a7809f7d02db1354a8d1d335031c76592a5e468 (patch)
tree40abcddd23e77ff52222fd3dff28febfa82269e0
parent5d600413dee1ad71d4bb6efc1597e1c3e334fb9b (diff)
downloadrabbitmq-server-8a7809f7d02db1354a8d1d335031c76592a5e468.tar.gz
Clarification of the comments in VQ
-rw-r--r--src/rabbit_variable_queue.erl15
1 files changed, 8 insertions, 7 deletions
diff --git a/src/rabbit_variable_queue.erl b/src/rabbit_variable_queue.erl
index 11e55353..1b86320b 100644
--- a/src/rabbit_variable_queue.erl
+++ b/src/rabbit_variable_queue.erl
@@ -91,7 +91,7 @@
%% calculate, given our current ingress and egress rates, how many
%% messages we should hold in RAM. We track the ingress and egress
%% rates for both messages and pending acks and rates for both are
-%% included when calculating the number of messages to hold in
+%% considered when calculating the number of messages to hold in
%% RAM. When we need to push alphas to betas or betas to gammas, we
%% favour writing out messages that are further from the head of the
%% queue. This minimises writes to disk, as the messages closer to the
@@ -179,12 +179,13 @@
%% written to disk, acks are stored in message form to avoid the
%% overhead of writing to disk.
%%
-%% During memory reduction, messages stored as transient ack records
-%% are pushed out to disk before messages in the queue. More
-%% precisely, messages from the queue will not be pushed out to disk
-%% while the number of messages stored for acks is greater than
-%% zero. Messages for acks are written to disk in batches of at most
-%% ?IO_BATCH_SIZE.
+%% During memory reduction, acks stored in message form are converted
+%% to tuple form, and the corresponding messages are pushed out to
+%% disk. Message form acks are always pushed to disk before messages
+%% stored in the queue. More precisely, messages from the queue will
+%% not be pushed out to disk while the number of messages form acks is
+%% greater than zero. Message form acks are converted to tuple form in
+%% batches of at most ?IO_BATCH_SIZE.
%%
%% Notes on Clean Shutdown
%% (This documents behaviour in variable_queue, queue_index and