Change RPC callQueue size from "handlerCount * MAX_QUEUE_SIZE_PER_HANDLER;"
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Key: HBASE-3813
URL: https://issues.apache.org/jira/browse/HBASE-3813
Project: HBase
Issue Type: Bug
Affects Versions: 0.90.3
Reporter: stack
Priority: Critical
Yesterday debugging w/ Jack we noticed that with few handlers on a big box, he
was seeing stats like this:
{code}
2011-04-21 11:54:49,451 DEBUG org.apache.hadoop.ipc.HBaseServer: Server
connection from X.X.X.X:60931; # active connections: 11; # queued calls: 2500
{code}
We had 2500 items in the rpc queue waiting to be processed.
Turns out he had too few handlers for number of clients (but also, it seems
like he figured hw issues in that his RAM bus was running at 1/4 the rate that
it should have been running at).
Chatting w/ J-D this morning, he asked if the queues hold 'data'. The queues
hold 'Calls'. Calls are the client request. They contain data.
Jack had 2500 items queued. If each item to insert was 1MB, thats 25k * 1MB of
memory that is outside of our generally accounting.
Currently the queue size is handlers * MAX_QUEUE_SIZE_PER_HANDLER where
MAX_QUEUE_SIZE_PER_HANDLER is hardcoded to be 100.
If the queue is full we block (LinkedBlockingQueue).
Going to change the queue size from 100 to 10 by default -- but also will make
it configurable and will doc. this as possible cause of OOME. Will try it on
production here before committing patch.
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