We only see this on the .META. region not otherwise... On Wed, Dec 5, 2012 at 4:37 PM, Varun Sharma <[email protected]> wrote:
> I see but is this pointing to the fact that we are heading to disk for > scanning META - if yes, that would be pretty bad, no ? Currently I am > trying to see if the freeze coincides with Block Cache being full (we have > an inmemory column) - is the META table cached just like other tables ? > > Varun > > > On Wed, Dec 5, 2012 at 4:20 PM, lars hofhansl <[email protected]> wrote: > >> Looks like you're running into HBASE-5898. >> >> >> >> ----- Original Message ----- >> From: Varun Sharma <[email protected]> >> To: [email protected] >> Cc: >> Sent: Wednesday, December 5, 2012 3:51 PM >> Subject: .META. region server DDOSed by too many clients >> >> Hi, >> >> I am running hbase 0.94.0 and I have a significant write load being put on >> a table with 98 regions on a 15 node cluster - also this write load comes >> from a very large number of clients (~ 1000). I am running with 10 >> priority >> IPC handlers and 200 IPC handlers. It seems the region server holding >> .META >> is DDOSed. All the 200 handlers are busy serving the .META. region and >> they >> are all locked onto on object. The Jstack is here for the regoin server >> >> "IPC Server handler 182 on 60020" daemon prio=10 tid=0x00007f329872c800 >> nid=0x4401 waiting on condition [0x00007f328807f000] >> java.lang.Thread.State: WAITING (parking) >> at sun.misc.Unsafe.park(Native Method) >> - parking to wait for <0x0000000542d72e30> (a >> java.util.concurrent.locks.ReentrantLock$NonfairSync) >> at >> java.util.concurrent.locks.LockSupport.park(LockSupport.java:186) >> at >> >> java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:838) >> at >> >> java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:871) >> at >> >> java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1201) >> at >> >> java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:214) >> at >> java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:290) >> at >> >> java.util.concurrent.ConcurrentHashMap$Segment.put(ConcurrentHashMap.java:445) >> at >> >> java.util.concurrent.ConcurrentHashMap.putIfAbsent(ConcurrentHashMap.java:925) >> at >> org.apache.hadoop.hbase.util.IdLock.getLockEntry(IdLock.java:71) >> at >> >> org.apache.hadoop.hbase.io.hfile.HFileReaderV2.readBlock(HFileReaderV2.java:290) >> at >> >> org.apache.hadoop.hbase.io.hfile.HFileBlockIndex$BlockIndexReader.seekToDataBlock(HFileBlockIndex.java:213) >> at >> >> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.seekTo(HFileReaderV2.java:455) >> at >> >> org.apache.hadoop.hbase.io.hfile.HFileReaderV2$AbstractScannerV2.reseekTo(HFileReaderV2.java:493) >> at >> >> org.apache.hadoop.hbase.regionserver.StoreFileScanner.reseekAtOrAfter(StoreFileScanner.java:242) >> at >> >> org.apache.hadoop.hbase.regionserver.StoreFileScanner.reseek(StoreFileScanner.java:167) >> at >> >> org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner.doRealSeek(NonLazyKeyValueScanner.java:54) >> at >> >> org.apache.hadoop.hbase.regionserver.KeyValueHeap.generalizedSeek(KeyValueHeap.java:299) >> at >> >> org.apache.hadoop.hbase.regionserver.KeyValueHeap.reseek(KeyValueHeap.java:244) >> at >> >> org.apache.hadoop.hbase.regionserver.StoreScanner.reseek(StoreScanner.java:521) >> - locked <0x000000063b4965d0> (a >> org.apache.hadoop.hbase.regionserver.StoreScanner) >> at >> >> org.apache.hadoop.hbase.regionserver.StoreScanner.next(StoreScanner.java:402) >> - locked <0x000000063b4965d0> (a >> org.apache.hadoop.hbase.regionserver.StoreScanner) >> at >> >> org.apache.hadoop.hbase.regionserver.KeyValueHeap.next(KeyValueHeap.java:127) >> at >> >> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.nextInternal(HRegion.java:3354) >> at >> >> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:3310) >> - locked <0x0000000523c211e0> (a >> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl) >> at >> >> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl.next(HRegion.java:3327) >> - locked <0x0000000523c211e0> (a >> org.apache.hadoop.hbase.regionserver.HRegion$RegionScannerImpl) >> at >> org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4066) >> at >> org.apache.hadoop.hbase.regionserver.HRegion.get(HRegion.java:4039) >> at >> >> org.apache.hadoop.hbase.regionserver.HRegionServer.get(HRegionServer.java:1941) >> >> The client side trace shows that we are looking for META region. >> >> thrift-worker-3499" daemon prio=10 tid=0x00007f789dd98800 nid=0xb52 >> waiting >> for monitor entry [0x00007f778672d000] >> java.lang.Thread.State: BLOCKED (on object monitor) >> at >> >> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegionInMeta(HConnectionManager.java:943) >> - waiting to lock <0x0000000707978298> (a java.lang.Object) >> at >> >> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.locateRegion(HConnectionManager.java:836) >> at >> >> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.processBatchCallback(HConnectionManager.java:1482) >> at >> >> org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.processBatch(HConnectionManager.java:1367) >> at org.apache.hadoop.hbase.client.HTable.batch(HTable.java:729) >> - locked <0x000000070821d5a0> (a >> org.apache.hadoop.hbase.client.HTable) >> at org.apache.hadoop.hbase.client.HTable.get(HTable.java:698) >> at >> >> org.apache.hadoop.hbase.client.HTablePool$PooledHTable.get(HTablePool.java:371) >> >> On the RS page, I see 68 million read requests for the META region while >> for the other 98 regions - we have done like 20 million write requests in >> total - regions have not moved around at all and no crashes have happened. >> Why do we have such an incredible number of scans over META and is there >> something I can do about this issue ? >> >> Varun >> >> >
