Dear All,
I am currently using Hadoop 0.23.1 with HBase 0.94.1 in a pseudo-distributed
mode. I am trying to use HBase Thrift API (not using Thrift2 yet) in a
nonblocking and async mode to insert a bulk of records. I am sharing the set of
steps for everyone's information and setting the context to my problem
Please find below the code that I am using for initializing the async client
TBinaryProtocol.Factory binProtoFactory=new TBinaryProtocol.Factory();
TAsyncClientManager clientManager=null;
TNonblockingSocket nonBlockingSocket=null;
try {
clientManager=new TAsyncClientManager();
} catch (IOException e) {
throw new RuntimeException(e);
}
try {
nonBlockingSocket=new TNonblockingSocket(HOST_NAME,PORT_NUMBER);
} catch (IOException e) {
throw new RuntimeException(e);
}
And, I am initializing the client as shown below
Hbase.AsyncClient client=new Hbase.AsyncClient(binProtoFactory, clientManager,
nonBlockingSocket);
I could see two ways of using the client, i.e. one client for all the records
to be inserted or separate instance of client for every record. I thought since
this is a non-blocking channel, it would make sense to initialize 1 client for
all the requests, since all the requests would be streamed using a framed
transport.
// 1 async client for all the requests
Hbase.AsyncClient client=new Hbase.AsyncClient(binProtoFactory, clientManager,
nonBlockingSocket);
// mutate rows called in a loop to insert multiple records, using the same
client
client.mutateRow(table, ByteBuffer.wrap(key), mutations,mutationAttributes,new
HBaseInsertAsyncHandler());
But soon I found that I was wrong as I got back the following error.
java.lang.IllegalStateException: Client is currently executing another method:
org.apache.hadoop.hbase.thrift.generated.Hbase$AsyncClient$mutateRow_call
at org.apache.thrift.async.TAsyncClient.checkReady(TAsyncClient.java:78)
at
org.apache.hadoop.hbase.thrift.generated.Hbase$AsyncClient.mutateRow(Hbase.java:2714)
Reading through the following JIRA educated me a bit more on this
https://issues.apache.org/jira/browse/THRIFT-945
So, I changed my code to initialize the client per record to be inserted.
//called both these statements for every record to be inserted in a loop
Hbase.AsyncClient client=new Hbase.AsyncClient(binProtoFactory, clientManager,
nonBlockingSocket);
client.mutateRow(table, ByteBuffer.wrap(key), mutations,mutationAttributes,new
HBaseInsertAsyncHandler());
Even this failed with the following error
2012-11-19 17:25:15,275 WARN [TAsyncClientManager#SelectorThread 9]
async.TAsyncClientManager (TAsyncClientManager.java:startPendingMethods(177)) -
Caught exception in TAsyncClientManager!
java.nio.channels.ClosedChannelException
at
java.nio.channels.spi.AbstractSelectableChannel.register(AbstractSelectableChannel.java:167)
at java.nio.channels.SelectableChannel.register(SelectableChannel.java:254)
at
org.apache.thrift.transport.TNonblockingSocket.registerSelector(TNonblockingSocket.java:99)
at org.apache.thrift.async.TAsyncMethodCall.start(TAsyncMethodCall.java:141)
at
org.apache.thrift.async.TAsyncClientManager$SelectThread.startPendingMethods(TAsyncClientManager.java:169)
at
org.apache.thrift.async.TAsyncClientManager$SelectThread.run(TAsyncClientManager.java:114)
So, it looked to me as if the channel registration could not happen in time for
it to get initialized and since the records are getting inserted in a loop, it
possibly needs a time window for initialization to get complete and insert the
record. So I had to introduce a delay for every such insertion, which I do not
prefer to do. The code changes for that are as shown below
Hbase.AsyncClient client=new Hbase.AsyncClient(binProtoFactory, clientManager,
nonBlockingSocket);
client.mutateRow(table, ByteBuffer.wrap(key), mutations,mutationAttributes,new
HBaseInsertAsyncHandler());
synchronized (client.getProtocolFactory()) {
client.getProtocolFactory().wait(20);
}
With the above change, I could see the records getting inserted into HBase
using async thrift client, but I think this is not the right solution and will
look for some guidance from the community to have a more consistent way to
utilize the the async thrift capability without any specific wait or sleep
times, as putting a wait call, kills the async advantage and introduces delays
in the overall throughput. Looking forward for your help.
Thanks and Regards
Pankaj Misra
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