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https://issues.apache.org/jira/browse/CASSANDRA-4032?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Peter Schuller updated CASSANDRA-4032:
--------------------------------------

    Description: 
Reproduce by just starting a fresh cassandra with a heap large enough for live 
ratio calculation (which is {{O(n)}}) to be insanely slow, and then running 
{{./bin/stress -d host -n100000000 -t10}}. With a large enough heap and default 
flushing behavior this is bad enough that stress gets timeouts.

Example ("blocked for" is my debug log added around submit()):

{code}
 INFO [MemoryMeter:1] 2012-03-09 15:07:30,857 Memtable.java (line 198) 
CFS(Keyspace='Keyspace1', ColumnFamily='Standard1') liveRatio is 
8.89014894083727 (just-counted was 8.89014894083727).  calculation took 28273ms 
for 1320245 columns
 WARN [MutationStage:8] 2012-03-09 15:07:30,857 Memtable.java (line 209) 
submit() blocked for: 231135
{code}

The calling code was written assuming a RejectedExecutionException is thrown, 
but it's not because {{DebuggableThreadPoolExecutor}} installs a blocking 
rejection handler.


  was:
Reproduce by just starting a fresh cassandra with a heap large enough for live 
ratio calculation (which is {{O(n)}}) to be insanely slow, and then running 
{{./bin/stress -d smf1-amv-01-sr1 -n100000000 -t10}}. With a large enough heap 
and default flushing behavior this is bad enough that stress gets timeouts.

Example ("blocked for" is my debug log added around submit()):

{code}
 INFO [MemoryMeter:1] 2012-03-09 15:07:30,857 Memtable.java (line 198) 
CFS(Keyspace='Keyspace1', ColumnFamily='Standard1') liveRatio is 
8.89014894083727 (just-counted was 8.89014894083727).  calculation took 28273ms 
for 1320245 columns
 WARN [MutationStage:8] 2012-03-09 15:07:30,857 Memtable.java (line 209) 
submit() blocked for: 231135
{code}

The calling code was written assuming a RejectedExecutionException is thrown, 
but it's not because {{DebuggableThreadPoolExecutor}} installs a blocking 
rejection handler.


    
> memtable.updateLiveRatio() is blocking, causing insane latencies for writes
> ---------------------------------------------------------------------------
>
>                 Key: CASSANDRA-4032
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-4032
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Peter Schuller
>            Assignee: Peter Schuller
>             Fix For: 1.1.0
>
>
> Reproduce by just starting a fresh cassandra with a heap large enough for 
> live ratio calculation (which is {{O(n)}}) to be insanely slow, and then 
> running {{./bin/stress -d host -n100000000 -t10}}. With a large enough heap 
> and default flushing behavior this is bad enough that stress gets timeouts.
> Example ("blocked for" is my debug log added around submit()):
> {code}
>  INFO [MemoryMeter:1] 2012-03-09 15:07:30,857 Memtable.java (line 198) 
> CFS(Keyspace='Keyspace1', ColumnFamily='Standard1') liveRatio is 
> 8.89014894083727 (just-counted was 8.89014894083727).  calculation took 
> 28273ms for 1320245 columns
>  WARN [MutationStage:8] 2012-03-09 15:07:30,857 Memtable.java (line 209) 
> submit() blocked for: 231135
> {code}
> The calling code was written assuming a RejectedExecutionException is thrown, 
> but it's not because {{DebuggableThreadPoolExecutor}} installs a blocking 
> rejection handler.

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