diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/rabbit_variable_queue.erl | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/src/rabbit_variable_queue.erl b/src/rabbit_variable_queue.erl index de1fdbf962..d50490544c 100644 --- a/src/rabbit_variable_queue.erl +++ b/src/rabbit_variable_queue.erl @@ -178,12 +178,12 @@ %% (betas+gammas+delta)/(target_ram_count+betas+gammas+delta). I.e. as %% the target_ram_count shrinks to 0, so must betas and gammas. %% -%% The conversion of betas to gammas is done in batches of at least -%% ?IO_BATCH_SIZE. This value should not be too small, otherwise the -%% frequent operations on the queues of q2 and q3 will not be -%% effectively amortised (switching the direction of queue access -%% defeats amortisation). Note that there is a natural upper bound due -%% to credit_flow limits on the alpha to beta conversion. +%% The conversion of betas to deltas is done if there are at least +%% ?IO_BATCH_SIZE betas in q2 & q3. This value should not be too small, +%% otherwise the frequent operations on the queues of q2 and q3 will not be +%% effectively amortised (switching the direction of queue access defeats +%% amortisation). Note that there is a natural upper bound due to credit_flow +%% limits on the alpha to beta conversion. %% %% The conversion from alphas to betas is chunked due to the %% credit_flow limits of the msg_store. This further smooths the @@ -2384,6 +2384,9 @@ reduce_memory_use(State = #vqstate { end, State3 = + %% If there are more messages with their queue position held in RAM, + %% a.k.a. betas, in Q2 & Q3 than IoBatchSize, + %% write their queue position to disk, a.k.a. push_betas_to_deltas case chunk_size(?QUEUE:len(Q2) + ?QUEUE:len(Q3), permitted_beta_count(State1)) of S2 when S2 >= IoBatchSize -> |