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Yuki Morishita commented on CASSANDRA-7546: ------------------------------------------- +1 to v2 (it lacks Locks.java but I assume it is unchanged). My concern is use of monitorEnter/monitorExit as I'm not sure the downside of those, but I don't think I have better alternative. [~graham.sanderson] can I go ahead and commit to 2.1 or you want me to wait until you do native_objects test? > AtomicSortedColumns.addAllWithSizeDelta has a spin loop that allocates memory > ----------------------------------------------------------------------------- > > Key: CASSANDRA-7546 > URL: https://issues.apache.org/jira/browse/CASSANDRA-7546 > Project: Cassandra > Issue Type: Bug > Components: Core > Reporter: graham sanderson > Assignee: graham sanderson > Fix For: 2.1.1 > > Attachments: 7546.20.txt, 7546.20_2.txt, 7546.20_3.txt, > 7546.20_4.txt, 7546.20_5.txt, 7546.20_6.txt, 7546.20_7.txt, 7546.20_7b.txt, > 7546.20_alt.txt, 7546.20_async.txt, 7546.21_v1.txt, > cassandra-2.1-7546-v2.txt, cassandra-2.1-7546.txt, graph2_7546.png, > graph3_7546.png, graphs1.png, hint_spikes.png, suggestion1.txt, > suggestion1_21.txt, young_gen_gc.png > > > In order to preserve atomicity, this code attempts to read, clone/update, > then CAS the state of the partition. > Under heavy contention for updating a single partition this can cause some > fairly staggering memory growth (the more cores on your machine the worst it > gets). > Whilst many usage patterns don't do highly concurrent updates to the same > partition, hinting today, does, and in this case wild (order(s) of magnitude > more than expected) memory allocation rates can be seen (especially when the > updates being hinted are small updates to different partitions which can > happen very fast on their own) - see CASSANDRA-7545 > It would be best to eliminate/reduce/limit the spinning memory allocation > whilst not slowing down the very common un-contended case. -- This message was sent by Atlassian JIRA (v6.3.4#6332)