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Update & clarify module doc for emqx_mqueue.erl

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spring2maz 2018-09-12 20:01:31 +02:00 committed by Feng Lee
parent 0c39a7620e
commit 8db9f3e81d
1 changed files with 8 additions and 5 deletions
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13
src/emqx_mqueue.erl
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@ -18,7 +18,7 @@
%%
%% This module implements a simple in-memory queue for MQTT persistent session.
%%
%% If the broker restarted or crashed, all the messages queued will be gone.
%% If the broker restarts or crashes, all queued messages will be lost.
%%
%% Concept of Message Queue and Inflight Window:
%%
@ -29,12 +29,15 @@
%% |<--- Win Size --->|
%%
%%
%% 1. Inflight Window to store the messages delivered and awaiting for puback.
%% 1. Inflight Window is to store the messages
%% that are delivered but still awaiting for puback.
%%
%% 2. Enqueue messages when the inflight window is full.
%% 2. Messages are enqueued to tail when the inflight window is full.
%%
%% 3. If the queue is full, dropped qos0 messages if store_qos0 is true,
%% otherwise dropped the oldest one.
%% 3. QoS=0 messages are only enqueued when `store_qos0' is given `true`
%% in init options
%%
%% 4. If the queue is full drop the oldest one unless `max_len' is set to `0'.
%%
%% @end