It helped, thanks. Now I have single reusable BufferedMutator instance and I don't call .close() after mutations, I call .flush() Is it ok?
2016-02-09 23:09 GMT+01:00 Stack <st...@duboce.net>: > On Tue, Feb 9, 2016 at 9:46 AM, Serega Sheypak <serega.shey...@gmail.com> > wrote: > > > I've modified my code: > > > > void saveUsers(Collection<User> users){ > > if(users && !users.isEmpty()){ > > > > // Get Connection instance, instance created once. , BM is > new > > for each request.' > > > > > If new for each request, don't bother using BM. Otherwise, put the BM in > same place you keep your Connection and just be sure to call close on BM > when your app goes down. > St.Ack > > > > > > > > def mutator = > > getConnection().getBufferedMutator(getBufferedMutatorParams()) > > > > List<Put> putList = users.collect{toPut(it)} > > mutator.mutate(putList) > > *mutator.close() // exception here* > > } > > } > > > > Exception is still thrown > > > > 2016-02-09 15:43 GMT+01:00 Stack <st...@duboce.net>: > > > > > On Tue, Feb 9, 2016 at 6:37 AM, Serega Sheypak < > serega.shey...@gmail.com > > > > > > wrote: > > > > > > > Hi, thanks for reply! > > > > > > > > > > > > > What should we add here to make the doc more clear on > > BufferedMutator? > > > > > > > > > > > > > > > > > > > http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/BufferedMutator.html > > > > It's pretty clear. > > > > > > > > > And in the example? > > > > Example shows that both connection and buffered mutator are thread > safe > > > and > > > > they are closed at once. > > > > - Should keep single instance of connection and bufferedmutator per > > > thread? > > > > > > > > > > No. Connection says you should generally share the Connection instance. > > > Ditto for BufferedMutator. It is backed by a buffer so you are batching > > > your writes when you use it. If you share the BM, your batching will > more > > > 'regular'. > > > > > > > > > > - Should I keep connection per thread and instantiate mutator for > each > > > > request? > > > > > > > > > > See above. > > > > > > > > > > - what happens if autoflush enabled? > > > > > > > > > > When the backing buffer is full, it gets flushed to the cluster. > > > > > > > > > > - is it possible to turn on sync mode for saving data? > > > > > > > > > > Yes. Don't use a BufferedMutator. Your throughput will go down as you > do > > an > > > RPC per write. > > > > > > > > > > - Connection could get into failed/invalid state for some reason (RS > > > down, > > > > RS up, some networking partitioned happend). Is it possible? > > > > > > > > > > > > It could happen but I think by now we've seen nearly all of the ways in > > > which a Connection can fail and internally, it compensates. > > > > > > > > > > > > > If it's > > > > possible, then what is the right way to handle it: "close" failed > > > > connection and ask for new one? > > > > > > > > > > > Good question. Connection internally will retry and 'ride over' near > all > > > cluster issues but the catastrophic. > > > > > > St.Ack > > > > > > > > > > > > > > I assume users is collection of User's. > > > > > Have you tried obtaining / closing mutator for each User instead of > > > > sharing > > > > > the mutator ? > > > > > > > > > If another flush, say because there were lots of puts, then when > > close > > > > > comes in, we are out of threads and you'd get below. > > > > Looks like it's the root cause, let me try! > > > > > > > > Thank you for detailed explanation! > > > > > > > > > > > > > > > > 2016-02-09 7:10 GMT+01:00 Stack <st...@duboce.net>: > > > > > > > > > On Mon, Feb 8, 2016 at 3:01 PM, Serega Sheypak < > > > serega.shey...@gmail.com > > > > > > > > > > wrote: > > > > > > > > > > > Hi, I'm confused with new HBase 1.0 API. API says that > application > > > > should > > > > > > manage connections (Previously HConnections) on their own. > Nothing > > is > > > > > > managed itnernally now. > > > > > > > > > > > > > > > > > That is right. > > > > > > > > > > > > > > > > > > > > > > > > > > Here is an example: > > > > > > > > > > > > > > > > > > > > > > > > > > > https://hbase.apache.org/xref/org/apache/hadoop/hbase/client/example/BufferedMutatorExample.html > > > > > > > > > > > > It gives no clue about lifecycle :( > > > > > > > > > > > > > > > > > > > > > Connection is fairly explicit: > > > > > > > > > > > > > > > > > > > > http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/Connection.html > > > > > > > > > > What should we add here to make the doc more clear on > > BufferedMutator? > > > > > > > > > > > > > > > > > > > > http://hbase.apache.org/apidocs/org/apache/hadoop/hbase/client/BufferedMutator.html > > > > > > > > > > And in the example? > > > > > > > > > > > > > > > > > > > > > Right now I create single connection instance for servlet and > > > > > > BufferedMutator per request. > > > > > > > > > > > > > > > > > > > > > > > The recommendation is a singled BufferedMutator shared across > > requests. > > > > > > > > > > > > > > > > > > > > > > > > > > //getConnection returns single instance, it doesn't return new > > > > connection > > > > > > each time > > > > > > def mutator = > > > > > > getConnection().getBufferedMutator(getBufferedMutatorParams()) > > > > > > > > > > > > > > > > > > > > > getConnection is your method? > > > > > > > > > > > > > > > getBufferedMutator creates a new one? > > > > > > > > > > > > > > > > > > > > > users.each{ mutator.mutate(toPut(it))} > > > > > > mutator.close() //exception is thrown here > > > > > > > > > > > > > > > > > The close is flushing out all the writes. > > > > > > > > > > If a BufferedMutator per servlet instance, there are probably many > > when > > > > > many requests coming in. > > > > > > > > > > See what happens when you create one: > > > > > > > > > > > > > > > > > > > > > > > > > http://hbase.apache.org/xref/org/apache/hadoop/hbase/client/ConnectionImplementation.html#313 > > > > > > > > > > which calls through to here.... > > > > > > > > > > > > > > > > > > > > http://hbase.apache.org/xref/org/apache/hadoop/hbase/client/HTable.html#126 > > > > > > > > > > ... which creates an executor of max 1 task only. > > > > > > > > > > If another flush, say because there were lots of puts, then when > > close > > > > > comes in, we are out of threads and you'd get below. > > > > > > > > > > St.Ack > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > And I get tons of exceptions thrown on "mutator.close()", what > do I > > > do > > > > > > wrong? > > > > > > > > > > > > WARNING: #905, the task was rejected by the pool. This is > > unexpected. > > > > > > Server is node04.server.com, 60020,1447338864601 > > > > > > java.util.concurrent.RejectedExecutionException: Task > > > > > > java.util.concurrent.FutureTask@5cff3b40 rejected from > > > > > > java.util.concurrent.ThreadPoolExecutor@686c2853[Terminated, > pool > > > > size = > > > > > > 0, > > > > > > active threads = 0, queued tasks = 0, completed tasks = 1] > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2047) > > > > > > at > > > > > > > > > > > > > > > > > > > > > java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:823) > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1369) > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > java.util.concurrent.AbstractExecutorService.submit(AbstractExecutorService.java:112) > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > org.apache.hadoop.hbase.client.AsyncProcess$AsyncRequestFutureImpl.sendMultiAction(AsyncProcess.java:956) > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > org.apache.hadoop.hbase.client.AsyncProcess$AsyncRequestFutureImpl.access$000(AsyncProcess.java:574) > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > org.apache.hadoop.hbase.client.AsyncProcess.submitMultiActions(AsyncProcess.java:423) > > > > > > at > > > > > > > > > > > > org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:403) > > > > > > at > > > > > > > > > > > > org.apache.hadoop.hbase.client.AsyncProcess.submit(AsyncProcess.java:320) > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > org.apache.hadoop.hbase.client.BufferedMutatorImpl.backgroundFlushCommits(BufferedMutatorImpl.java:206) > > > > > > at > > > > > > > > > > > > > > > > > > > > > > > > > > > org.apache.hadoop.hbase.client.BufferedMutatorImpl.close(BufferedMutatorImpl.java:158) > > > > > > at > > > org.apache.hadoop.hbase.client.BufferedMutator$close$0.call(Unknown > > > > > > Source) > > > > > > > > > > > > > > > > > > > > >