Hi,

We have changed some parameters on our 16(!) region servers : 1GB
more -Xmx, more rpc handler (from 10 to 30) longer timeout, but
nothing seems to improve the response time:

- Scans with HBase 0.92  are x3 SLOWER than with HBase 0.90.3
- A lot of simultaneous gets lead to a huge slow down of batch put &
ramdom read response time

... despite the fact that our RS CPU load is really low (10%)

Note: we have not (yet) activated MSlabs, nor direct read on HDFS.

Any idea please ? I'm really stuck on that issue.

Best regards,

Le 16/11/12 20:55, Vincent Barat a �crit :
> Hi,
>
> Right now (and previously with 0.90.3) we were using the default
> value (10).
> We are trying right now to increase to 30 to see if it is better.
>
> Thanks for your concern
>
> Le 16/11/12 18:13, Ted Yu a �crit :
>> Vincent:
>> What's the value for hbase.regionserver.handler.count ?
>>
>> I assume you keep the same value as that from 0.90.3
>>
>> Thanks
>>
>> On Fri, Nov 16, 2012 at 8:14 AM, Vincent
>> Barat<[EMAIL PROTECTED]>wrote:
>>
>>> Le 16/11/12 01:56, Stack a �crit :
>>>
>>>   On Thu, Nov 15, 2012 at 5:21 AM, Guillaume
>>> Perrot<[EMAIL PROTECTED]>
>>>> wrote:
>>>>
>>>>> It happens when several tables are being compacted and/or when
>>>>> there is
>>>>> several scanners running.
>>>>>
>>>> It happens for a particular region?  Anything you can tell
>>>> about the
>>>> server looking in your cluster monitoring?  Is it running hot?  
>>>> What
>>>> do the hbase regionserver stats in UI say?  Anything
>>>> interesting about
>>>> compaction queues or requests?
>>>>
>>> Hi, thanks for your answser Stack. I will take the lead on that
>>> thread
>>> from now on.
>>>
>>> It does not happens on any particular region. Actually, things
>>> get better
>>> now since compactions have been performed on all tables and have
>>> been
>>> stopped.
>>>
>>> Nevertheless, we face a dramatic decrease of performances
>>> (especially on
>>> random gets) of the overall cluster:
>>>
>>> Despite the fact we double our number of region servers (from 8
>>> to 16) and
>>> despite the fact that these region server CPU load are just
>>> about 10% to
>>> 30%, performances are really bad : very often an light increase
>>> of request
>>> lead to a clients locked on request, very long response time. It
>>> looks like
>>> a contention / deadlock somewhere in the HBase client and C code.
>>>
>>>
>>>
>>>> If you look at the thread dump all handlers are occupied serving
>>>> requests?  These timedout requests couldn't get into the server?
>>>>
>>> We will investigate on that and report to you.
>>>
>>>
>>>   Before the timeouts, we observe an increasing CPU load on a
>>> single region
>>>>> server and if we add region servers and wait for rebalancing,
>>>>> we always
>>>>> have the same region server causing problems like these:
>>>>>
>>>>> 2012-11-14 20:47:08,443 WARN
>>>>> org.apache.hadoop.ipc.**HBaseServer: IPC
>>>>> Server Responder, call
>>>>> multi(org.apache.hadoop.hbase.**client.MultiAction@2c3da1aa), rpc
>>>>> version=1, client version=29, methodsFingerPrint=54742778 from
>>>>> <ip>:45334: output error
>>>>> 2012-11-14 20:47:08,443 WARN
>>>>> org.apache.hadoop.ipc.**HBaseServer: IPC
>>>>> Server handler 3 on 60020 caught: java.nio.channels.**
>>>>> ClosedChannelException
>>>>> at sun.nio.ch.SocketChannelImpl.**ensureWriteOpen(**
>>>>> SocketChannelImpl.java:133)
>>>>> at
>>>>> sun.nio.ch.SocketChannelImpl.**write(SocketChannelImpl.java:**324)
>>>>>
>>>>> at
>>>>> org.apache.hadoop.hbase.ipc.**HBaseServer.channelWrite(**
>>>>> HBaseServer.java:1653)
>>>>> at
>>>>> org.apache.hadoop.hbase.ipc.**HBaseServer$Responder.
>>>>> processResponse(HBaseServer.**java:924)
>>>>> at
>>>>> org.apache.hadoop.hbase.ipc.**HBaseServer$Responder.
>>>>> doRespond(HBaseServer.java:**1003)
>>>>> at
>>>>> org.apache.hadoop.hbase.ipc.**HBaseServer$Call.**sendResponseIfReady(
>>>>>
>>>>> HBaseServer.java:409)
>>>>> at
>>>>> org.apache.hadoop.hbase.ipc.**HBaseServer$Handler.run(**

On Tue, Nov 20, 2012 at 8:21 AM, Vincent Barat <[EMAIL PROTECTED]> wrote:
> We have changed some parameters on our 16(!) region servers : 1GB more -Xmx,
> more rpc handler (from 10 to 30) longer timeout, but nothing seems to
> improve the response time:
>

You have taken a look at the perf chapter Vincent:
http://hbase.apache.org/book.html#performance

You carried forward your old hbase-default.xml or did you remove it
(0.92 should have defaults in hbase-X.X.X.jar -- some defaults will
have changed).
> - Scans with HBase 0.92  are x3 SLOWER than with HBase 0.90.3

Any scan caching going on?
> - A lot of simultaneous gets lead to a huge slow down of batch put & ramdom
> read response time
>

The gets are returning lots of data? (If you thread dump the server at
this time -- see at top of the regionserver UI -- can you see what we
are hung up on?  Are all handlers occupied?).
> ... despite the fact that our RS CPU load is really low (10%)
>

As has been suggested earlier, perhaps up the handlers?
> Note: we have not (yet) activated MSlabs, nor direct read on HDFS.
>

MSlab will help you avoid stop-the-world GCs.  Direct read of HDFS
should speed up random access.

St.Ack

> Any idea please ? I'm really stuck on that issue.
>
> Best regards,
>
> Le 16/11/12 20:55, Vincent Barat a écrit :
>>
>> Hi,
>>
>> Right now (and previously with 0.90.3) we were using the default value
>> (10).
>> We are trying right now to increase to 30 to see if it is better.
>>
>> Thanks for your concern
>>
>> Le 16/11/12 18:13, Ted Yu a écrit :
>>>
>>> Vincent:
>>> What's the value for hbase.regionserver.handler.count ?
>>>
>>> I assume you keep the same value as that from 0.90.3
>>>
>>> Thanks
>>>
>>> On Fri, Nov 16, 2012 at 8:14 AM, Vincent
>>> Barat<[EMAIL PROTECTED]>wrote:
>>>
>>>> Le 16/11/12 01:56, Stack a écrit :
>>>>
>>>>   On Thu, Nov 15, 2012 at 5:21 AM, Guillaume Perrot<[EMAIL PROTECTED]>
>>>>>
>>>>> wrote:
>>>>>
>>>>>> It happens when several tables are being compacted and/or when there
>>>>>> is
>>>>>> several scanners running.
>>>>>>
>>>>> It happens for a particular region?  Anything you can tell about the
>>>>> server looking in your cluster monitoring?  Is it running hot?  What
>>>>> do the hbase regionserver stats in UI say?  Anything interesting about
>>>>> compaction queues or requests?
>>>>>
>>>> Hi, thanks for your answser Stack. I will take the lead on that thread
>>>> from now on.
>>>>
>>>> It does not happens on any particular region. Actually, things get
>>>> better
>>>> now since compactions have been performed on all tables and have been
>>>> stopped.
>>>>
>>>> Nevertheless, we face a dramatic decrease of performances (especially on
>>>> random gets) of the overall cluster:
>>>>
>>>> Despite the fact we double our number of region servers (from 8 to 16)
>>>> and
>>>> despite the fact that these region server CPU load are just about 10% to
>>>> 30%, performances are really bad : very often an light increase of
>>>> request
>>>> lead to a clients locked on request, very long response time. It looks
>>>> like
>>>> a contention / deadlock somewhere in the HBase client and C code.
>>>>
>>>>
>>>>
>>>>> If you look at the thread dump all handlers are occupied serving
>>>>> requests?  These timedout requests couldn't get into the server?
>>>>>
>>>> We will investigate on that and report to you.
>>>>
>>>>
>>>>   Before the timeouts, we observe an increasing CPU load on a single
>>>> region
>>>>>>
>>>>>> server and if we add region servers and wait for rebalancing, we
>>>>>> always
>>>>>> have the same region server causing problems like these:
>>>>>>
>>>>>> 2012-11-14 20:47:08,443 WARN org.apache.hadoop.ipc.**HBaseServer: IPC
>>>>>> Server Responder, call
>>>>>> multi(org.apache.hadoop.hbase.**client.MultiAction@2c3da1aa), rpc
>>>>>> version=1, client version=29, methodsFingerPrint=54742778 from
>>>>>> <ip>:45334: output error
>>>>>> 2012-11-14 20:47:08,443 WARN org.apache.hadoop.ipc.**HBaseServer: IPC
>>>>>> Server handler 3 on 60020 caught: java.nio.channels.**

Le 21/11/12 06:05, Stack a �crit :
> On Tue, Nov 20, 2012 at 8:21 AM, Vincent Barat <[EMAIL PROTECTED]> wrote:
>> We have changed some parameters on our 16(!) region servers : 1GB more -Xmx,
>> more rpc handler (from 10 to 30) longer timeout, but nothing seems to
>> improve the response time:
>>
> You have taken a look at the perf chapter Vincent:
> http://hbase.apache.org/book.html#performance
>
> You carried forward your old hbase-default.xml or did you remove it
> (0.92 should have defaults in hbase-X.X.X.jar -- some defaults will
> have changed).
We use the new default settings for HBase, just a few changes (more
RPC handlers and longer timeout (but this last was a bad idea).
>> - Scans with HBase 0.92  are x3 SLOWER than with HBase 0.90.3
> Any scan caching going on?
yes the cache is set between 64 and 1024 depending on the need
>> - A lot of simultaneous gets lead to a huge slow down of batch put & ramdom
>> read response time
>>
> The gets are returning lots of data? (If you thread dump the server at
> this time -- see at top of the regionserver UI -- can you see what we
> are hung up on?  Are all handlers occupied?).
We will check this...
>> ... despite the fact that our RS CPU load is really low (10%)
>>
> As has been suggested earlier, perhaps up the handlers?
>
>
>> Note: we have not (yet) activated MSlabs, nor direct read on HDFS.
>>
> MSlab will help you avoid stop-the-world GCs.  Direct read of HDFS
> should speed up random access.
OK, I guess we will give it a try, but on a second step.

Thansk for your help
>
> St.Ack
>
>> Any idea please ? I'm really stuck on that issue.
>>
>> Best regards,
>>
>> Le 16/11/12 20:55, Vincent Barat a �crit :
>>> Hi,
>>>
>>> Right now (and previously with 0.90.3) we were using the default value
>>> (10).
>>> We are trying right now to increase to 30 to see if it is better.
>>>
>>> Thanks for your concern
>>>
>>> Le 16/11/12 18:13, Ted Yu a �crit :
>>>> Vincent:
>>>> What's the value for hbase.regionserver.handler.count ?
>>>>
>>>> I assume you keep the same value as that from 0.90.3
>>>>
>>>> Thanks
>>>>
>>>> On Fri, Nov 16, 2012 at 8:14 AM, Vincent
>>>> Barat<[EMAIL PROTECTED]>wrote:
>>>>
>>>>> Le 16/11/12 01:56, Stack a �crit :
>>>>>
>>>>>    On Thu, Nov 15, 2012 at 5:21 AM, Guillaume Perrot<[EMAIL PROTECTED]>
>>>>>> wrote:
>>>>>>
>>>>>>> It happens when several tables are being compacted and/or when there
>>>>>>> is
>>>>>>> several scanners running.
>>>>>>>
>>>>>> It happens for a particular region?  Anything you can tell about the
>>>>>> server looking in your cluster monitoring?  Is it running hot?  What
>>>>>> do the hbase regionserver stats in UI say?  Anything interesting about
>>>>>> compaction queues or requests?
>>>>>>
>>>>> Hi, thanks for your answser Stack. I will take the lead on that thread
>>>>> from now on.
>>>>>
>>>>> It does not happens on any particular region. Actually, things get
>>>>> better
>>>>> now since compactions have been performed on all tables and have been
>>>>> stopped.
>>>>>
>>>>> Nevertheless, we face a dramatic decrease of performances (especially on
>>>>> random gets) of the overall cluster:
>>>>>
>>>>> Despite the fact we double our number of region servers (from 8 to 16)
>>>>> and
>>>>> despite the fact that these region server CPU load are just about 10% to
>>>>> 30%, performances are really bad : very often an light increase of
>>>>> request
>>>>> lead to a clients locked on request, very long response time. It looks
>>>>> like
>>>>> a contention / deadlock somewhere in the HBase client and C code.
>>>>>
>>>>>
>>>>>
>>>>>> If you look at the thread dump all handlers are occupied serving
>>>>>> requests?  These timedout requests couldn't get into the server?
>>>>>>
>>>>> We will investigate on that and report to you.
>>>>>
>>>>>
>>>>>    Before the timeouts, we observe an increasing CPU load on a single
>>>>> region
>>>>>>> server and if we add region servers and wait for rebalancing, we
>>>>>>> always
>>>>>>> have the same region server causing problems like these:

Do your PUTs and GETs have small amounts of data? If yes, then you can
increase the number of handlers.
We have a 8-node cluster on 0.92.1, and these are some of the setting
we changed from 0.90.4

hbase.regionserver.handler.count = 150
hbase.hregion.max.filesize=2147483648 (2GB)

The regions servers are run with a 16GB heap (-Xmx16000M)

With these settings, at peak we can handle ~2K concurrent clients.

Alok

On Tue, Nov 20, 2012 at 8:21 AM, Vincent Barat <[EMAIL PROTECTED]> wrote:
> Hi,
>
> We have changed some parameters on our 16(!) region servers : 1GB more -Xmx,
> more rpc handler (from 10 to 30) longer timeout, but nothing seems to
> improve the response time:
>
> - Scans with HBase 0.92  are x3 SLOWER than with HBase 0.90.3
> - A lot of simultaneous gets lead to a huge slow down of batch put & ramdom
> read response time
>
> ... despite the fact that our RS CPU load is really low (10%)
>
> Note: we have not (yet) activated MSlabs, nor direct read on HDFS.
>
> Any idea please ? I'm really stuck on that issue.
>
> Best regards,
>
> Le 16/11/12 20:55, Vincent Barat a écrit :
>>
>> Hi,
>>
>> Right now (and previously with 0.90.3) we were using the default value
>> (10).
>> We are trying right now to increase to 30 to see if it is better.
>>
>> Thanks for your concern
>>
>> Le 16/11/12 18:13, Ted Yu a écrit :
>>>
>>> Vincent:
>>> What's the value for hbase.regionserver.handler.count ?
>>>
>>> I assume you keep the same value as that from 0.90.3
>>>
>>> Thanks
>>>
>>> On Fri, Nov 16, 2012 at 8:14 AM, Vincent
>>> Barat<[EMAIL PROTECTED]>wrote:
>>>
>>>> Le 16/11/12 01:56, Stack a écrit :
>>>>
>>>>   On Thu, Nov 15, 2012 at 5:21 AM, Guillaume Perrot<[EMAIL PROTECTED]>
>>>>>
>>>>> wrote:
>>>>>
>>>>>> It happens when several tables are being compacted and/or when there
>>>>>> is
>>>>>> several scanners running.
>>>>>>
>>>>> It happens for a particular region?  Anything you can tell about the
>>>>> server looking in your cluster monitoring?  Is it running hot?  What
>>>>> do the hbase regionserver stats in UI say?  Anything interesting about
>>>>> compaction queues or requests?
>>>>>
>>>> Hi, thanks for your answser Stack. I will take the lead on that thread
>>>> from now on.
>>>>
>>>> It does not happens on any particular region. Actually, things get
>>>> better
>>>> now since compactions have been performed on all tables and have been
>>>> stopped.
>>>>
>>>> Nevertheless, we face a dramatic decrease of performances (especially on
>>>> random gets) of the overall cluster:
>>>>
>>>> Despite the fact we double our number of region servers (from 8 to 16)
>>>> and
>>>> despite the fact that these region server CPU load are just about 10% to
>>>> 30%, performances are really bad : very often an light increase of
>>>> request
>>>> lead to a clients locked on request, very long response time. It looks
>>>> like
>>>> a contention / deadlock somewhere in the HBase client and C code.
>>>>
>>>>
>>>>
>>>>> If you look at the thread dump all handlers are occupied serving
>>>>> requests?  These timedout requests couldn't get into the server?
>>>>>
>>>> We will investigate on that and report to you.
>>>>
>>>>
>>>>   Before the timeouts, we observe an increasing CPU load on a single
>>>> region
>>>>>>
>>>>>> server and if we add region servers and wait for rebalancing, we
>>>>>> always
>>>>>> have the same region server causing problems like these:
>>>>>>
>>>>>> 2012-11-14 20:47:08,443 WARN org.apache.hadoop.ipc.**HBaseServer: IPC
>>>>>> Server Responder, call
>>>>>> multi(org.apache.hadoop.hbase.**client.MultiAction@2c3da1aa), rpc
>>>>>> version=1, client version=29, methodsFingerPrint=54742778 from
>>>>>> <ip>:45334: output error
>>>>>> 2012-11-14 20:47:08,443 WARN org.apache.hadoop.ipc.**HBaseServer: IPC
>>>>>> Server handler 3 on 60020 caught: java.nio.channels.**
>>>>>> ClosedChannelException
>>>>>> at sun.nio.ch.SocketChannelImpl.**ensureWriteOpen(**
>>>>>> SocketChannelImpl.java:133)
>>>>>> at sun.nio.ch.SocketChannelImpl.**write(SocketChannelImpl.java:**324)

Hi,

I've checked my 30 RPC handler, they are all in a WAITING state:

Here is some extract for one of our RS (this is similar to all of them):

requestsPerSecond=593, numberOfOnlineRegions=584,
numberOfStores=1147, numberOfStorefiles=1980,
storefileIndexSizeMB=15, rootIndexSizeKB=16219,
totalStaticIndexSizeKB=246127, totalStaticBloomSizeKB=12936,
memstoreSizeMB=1421, readRequestsCount=633241097,
writeRequestsCount=9375846, compactionQueueSize=0, flushQueueSize=0,
usedHeapMB=3042, maxHeapMB=4591, blockCacheSizeMB=890.19,
blockCacheFreeMB=257.65, blockCacheCount=14048,
blockCacheHitCount=5854936149, blockCacheMissCount=14761288,
blockCacheEvictedCount=4870523, blockCacheHitRatio=99%,
blockCacheHitCachingRatio=99%, hdfsBlocksLocalityIndex=29

Le 21/11/12 05:53, Alok Singh a �crit :
> Do your PUTs and GETs have small amounts of data? If yes, then you can
> increase the number of handlers.
> We have a 8-node cluster on 0.92.1, and these are some of the setting
> we changed from 0.90.4
>
> hbase.regionserver.handler.count = 150
> hbase.hregion.max.filesize=2147483648 (2GB)
>
> The regions servers are run with a 16GB heap (-Xmx16000M)
>
> With these settings, at peak we can handle ~2K concurrent clients.
>
> Alok
>
> On Tue, Nov 20, 2012 at 8:21 AM, Vincent Barat <[EMAIL PROTECTED]> wrote:
>> Hi,
>>
>> We have changed some parameters on our 16(!) region servers : 1GB more -Xmx,
>> more rpc handler (from 10 to 30) longer timeout, but nothing seems to
>> improve the response time:
>>
>> - Scans with HBase 0.92  are x3 SLOWER than with HBase 0.90.3
>> - A lot of simultaneous gets lead to a huge slow down of batch put & ramdom
>> read response time
>>
>> ... despite the fact that our RS CPU load is really low (10%)
>>
>> Note: we have not (yet) activated MSlabs, nor direct read on HDFS.
>>
>> Any idea please ? I'm really stuck on that issue.
>>
>> Best regards,
>>
>> Le 16/11/12 20:55, Vincent Barat a �crit :
>>> Hi,
>>>
>>> Right now (and previously with 0.90.3) we were using the default value
>>> (10).
>>> We are trying right now to increase to 30 to see if it is better.
>>>
>>> Thanks for your concern
>>>
>>> Le 16/11/12 18:13, Ted Yu a �crit :
>>>> Vincent:
>>>> What's the value for hbase.regionserver.handler.count ?
>>>>
>>>> I assume you keep the same value as that from 0.90.3
>>>>
>>>> Thanks
>>>>
>>>> On Fri, Nov 16, 2012 at 8:14 AM, Vincent
>>>> Barat<[EMAIL PROTECTED]>wrote:
>>>>
>>>>> Le 16/11/12 01:56, Stack a �crit :
>>>>>
>>>>>    On Thu, Nov 15, 2012 at 5:21 AM, Guillaume Perrot<[EMAIL PROTECTED]>
>>>>>> wrote:
>>>>>>
>>>>>>> It happens when several tables are being compacted and/or when there
>>>>>>> is
>>>>>>> several scanners running.
>>>>>>>
>>>>>> It happens for a particular region?  Anything you can tell about the
>>>>>> server looking in your cluster monitoring?  Is it running hot?  What
>>>>>> do the hbase regionserver stats in UI say?  Anything interesting about
>>>>>> compaction queues or requests?
>>>>>>
>>>>> Hi, thanks for your answser Stack. I will take the lead on that thread
>>>>> from now on.
>>>>>
>>>>> It does not happens on any particular region. Actually, things get
>>>>> better
>>>>> now since compactions have been performed on all tables and have been
>>>>> stopped.
>>>>>
>>>>> Nevertheless, we face a dramatic decrease of performances (especially on
>>>>> random gets) of the overall cluster:
>>>>>
>>>>> Despite the fact we double our number of region servers (from 8 to 16)
>>>>> and
>>>>> despite the fact that these region server CPU load are just about 10% to
>>>>> 30%, performances are really bad : very often an light increase of
>>>>> request
>>>>> lead to a clients locked on request, very long response time. It looks
>>>>> like
>>>>> a contention / deadlock somewhere in the HBase client and C code.
>>>>>
>>>>>
>>>>>
>>>>>> If you look at the thread dump all handlers are occupied serving
>>>>>> requests?  These timedout requests couldn't get into the server?
>>>>>
*Vincent Barat*
*CTO
* logo
*Contact info *
[EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]%20>
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Hi,

I've checked my 30 RPC handlers, they are all in a WAITING state:

Thread 89 (PRI IPC Server handler 6 on 60020):
   State: WAITING
   Blocked count: 238
   Waited count: 617
   Waiting on
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject@131f139b
   Stack:
     sun.misc.Unsafe.park(Native Method)
java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1299)
Here is some extract for one of our RS (this is similar to all of them):

requestsPerSecond=593, numberOfOnlineRegions=584,
numberOfStores=1147, numberOfStorefiles=1980,
storefileIndexSizeMB=15, rootIndexSizeKB=16219,
totalStaticIndexSizeKB=246127, totalStaticBloomSizeKB=12936,
memstoreSizeMB=1421, readRequestsCount=633241097,
writeRequestsCount=9375846, compactionQueueSize=0, flushQueueSize=0,
usedHeapMB=3042, maxHeapMB=4591, blockCacheSizeMB=890.19,
blockCacheFreeMB=257.65, blockCacheCount=14048,
blockCacheHitCount=5854936149, blockCacheMissCount=14761288,
blockCacheEvictedCount=4870523, blockCacheHitRatio=99%,
blockCacheHitCachingRatio=99%, hdfsBlocksLocalityIndex=29

Maybe soem advice ?

Le 21/11/12 05:53, Alok Singh a �crit :
> Do your PUTs and GETs have small amounts of data? If yes, then you can
> increase the number of handlers.
> We have a 8-node cluster on 0.92.1, and these are some of the setting
> we changed from 0.90.4
>
> hbase.regionserver.handler.count = 150
> hbase.hregion.max.filesize=2147483648 (2GB)
>
> The regions servers are run with a 16GB heap (-Xmx16000M)
>
> With these settings, at peak we can handle ~2K concurrent clients.
>
> Alok
>
> On Tue, Nov 20, 2012 at 8:21 AM, Vincent Barat<[EMAIL PROTECTED]>  wrote:
>> Hi,
>>
>> We have changed some parameters on our 16(!) region servers : 1GB more -Xmx,
>> more rpc handler (from 10 to 30) longer timeout, but nothing seems to
>> improve the response time:
>>
>> - Scans with HBase 0.92  are x3 SLOWER than with HBase 0.90.3
>> - A lot of simultaneous gets lead to a huge slow down of batch put & ramdom
>> read response time
>>
>> ... despite the fact that our RS CPU load is really low (10%)
>>
>> Note: we have not (yet) activated MSlabs, nor direct read on HDFS.
>>
>> Any idea please ? I'm really stuck on that issue.
>>
>> Best regards,
>>
>> Le 16/11/12 20:55, Vincent Barat a �crit :
>>> Hi,
>>>
>>> Right now (and previously with 0.90.3) we were using the default value
>>> (10).
>>> We are trying right now to increase to 30 to see if it is better.
>>>
>>> Thanks for your concern
>>>
>>> Le 16/11/12 18:13, Ted Yu a �crit :
>>>> Vincent:
>>>> What's the value for hbase.regionserver.handler.count ?
>>>>
>>>> I assume you keep the same value as that from 0.90.3
>>>>
>>>> Thanks
>>>>
>>>> On Fri, Nov 16, 2012 at 8:14 AM, Vincent
>>>> Barat<[EMAIL PROTECTED]>wrote:
>>>>
>>>>> Le 16/11/12 01:56, Stack a �crit :
>>>>>
>>>>>    On Thu, Nov 15, 2012 at 5:21 AM, Guillaume Perrot<[EMAIL PROTECTED]>
>>>>>> wrote:
>>>>>>
>>>>>>> It happens when several tables are being compacted and/or when there
>>>>>>> is
>>>>>>> several scanners running.
>>>>>>>
>>>>>> It happens for a particular region?  Anything you can tell about the
>>>>>> server looking in your cluster monitoring?  Is it running hot?  What
>>>>>> do the hbase regionserver stats in UI say?  Anything interesting about
>>>>>> compaction queues or requests?
>>>>>>
>>>>> Hi, thanks for your answser Stack. I will take the lead on that thread
>>>>> from now on.
>>>>>
>>>>> It does not happens on any particular region. Actually, things get
>>>>> better
>>>>> now since compactions have been performed on all tables and have been
>>>>> stopped.
>>>>>
>>>>> Nevertheless, we face a dramatic decrease of performances (especially on
>>>>> random gets) of the overall cluster:

On Wed, Nov 21, 2012 at 1:04 AM, Vincent Barat <[EMAIL PROTECTED]> wrote:
> Hi,
>
> I've checked my 30 RPC handlers, they are all in a WAITING state:
>
> Thread 89 (PRI IPC Server handler 6 on 60020):
>   State: WAITING
>   Blocked count: 238
>   Waited count: 617
>   Waiting on
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject@131f139b
>   Stack:
>     sun.misc.Unsafe.park(Native Method)
> java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
> java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1987)
> java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:399)
> org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1299)
>

So Vincent, the servers are quiet?   Which would match your low CPU
observation.  Clients are unable to send them load for some reason?
How many disks.  What is your block cache hit number (see regionserver
log -- it gets printed every so often .... or in the below I see 99%
so your numbers should be good coming out of the regionserver).

>
>
> Here is some extract for one of our RS (this is similar to all of them):
>
> requestsPerSecond=593, numberOfOnlineRegions=584, numberOfStores=1147,
> numberOfStorefiles=1980, storefileIndexSizeMB=15, rootIndexSizeKB=16219,
> totalStaticIndexSizeKB=246127, totalStaticBloomSizeKB=12936,
> memstoreSizeMB=1421, readRequestsCount=633241097,
> writeRequestsCount=9375846, compactionQueueSize=0, flushQueueSize=0,
> usedHeapMB=3042, maxHeapMB=4591, blockCacheSizeMB=890.19,
> blockCacheFreeMB=257.65, blockCacheCount=14048,
> blockCacheHitCount=5854936149, blockCacheMissCount=14761288,
> blockCacheEvictedCount=4870523, blockCacheHitRatio=99%,
> blockCacheHitCachingRatio=99%, hdfsBlocksLocalityIndex=29
>

600 regions is a lot per server.  You should put it on your TODO list
to have less per server -- bigger regions which you can do now you are
on 0.92.

If you major compact -- do it when site is less heavily loaded -- does
our performance go up.

Are all query types slow or just certain types?

St.Ack

Le 21/11/12 18:39, Stack a �crit :
> So Vincent, the servers are quiet?   Which would match your low CPU
> observation.  Clients are unable to send them load for some reason?
> How many disks.  What is your block cache hit number (see regionserver
> log -- it gets printed every so often .... or in the below I see 99%
> so your numbers should be good coming out of the regionserver).
It does not seem to be a load issue : as you say CPU is low and RPC
handlers are under used.
We got plenty of disk space, and or block cache hit is 99% on all
region servers...

Today we tried to remove some region servers (yes: we had only 8
before moving to 0.92, and we added 8 more because we thought it was
a performance issue).
We now have 12 of them, are actually the perfs are similar (just
more CPU load of course, but similar response time).
> 600 regions is a lot per server.  You should put it on your TODO list
> to have less per server -- bigger regions which you can do now you are
> on 0.92.
This is definitively in our TODO. Nevertheless, our 8 RS (0.90.3)
before the move had more than 1100 regions each! Without any issue.
We increased or region size by X4 (now we use default 1GB setting).
And we plan to merge some tables.
>
> If you major compact -- do it when site is less heavily loaded -- does
> our performance go up.
>
> Are all query types slow or just certain types?
actually thing are ok for a time (say 2 to 4ms response time) then
we got "scanner lease" exeptions... We cannot figure out what
triggers this exception (we though it was a contention somewhere, or
a server slow down, but our last investigation seem to point a bug
between server and clients).

Here is a typical set of exceptiojn we have from time to time:

client (a PIG script using HBaseStorage):
----------------------------------

2012-11-21 14:47:29,925 | ERROR | main | Launcher   | Backend error
message
org.apache.hadoop.hbase.regionserver.LeaseException:
org.apache.hadoop.hbase.regionserver.LeaseException: lease
'4537659031468873643' does not exist
         at
org.apache.hadoop.hbase.regionserver.Leases.removeLease(Leases.java:231)
         at
org.apache.hadoop.hbase.regionserver.HRegionServer.next(HRegionServer.java:2117)
         at sun.reflect.GeneratedMethodAccessor25.invoke(Unknown Source)
         at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
         at java.lang.reflect.Method.invoke(Method.java:597)
         at
org.apache.hadoop.hbase.ipc.WritableRpcEngine$Server.call(WritableRpcEngine.java:364)
         at
org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1326)

         at
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
         at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
         at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
         at
java.lang.reflect.Constructor.newInstance(Constructor.java:513)
         at
org.apache.hadoop.hbase.RemoteExceptionHandler.decodeRemoteException(RemoteExceptionHandler.java:96)
         at
org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:84)
         at
org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:39)
         at
org.apache.hadoop.hbase.client.HConnectionManager$HConnectionImplementation.getRegionServerWithRetries(HConnectionManager.java:1325)
         at
org.apache.hadoop.hbase.client.HTable$ClientScanner.next(HTable.java:1293)
         at
org.apache.hadoop.hbase.mapreduce.TableRecordReaderImpl.nextKeyValue(TableRecordReaderImpl.java:133)
         at
org.apache.hadoop.hbase.mapreduce.TableRecordReader.nextKeyValue(TableRecordReader.java:142)
         at
org.apache.pig.backend.hadoop.hbase.HBaseTableInputFormat$HBaseTableRecordReader.nextKeyValue(HBaseTableInputFormat.java:162)
         at
org.apache.pig.backend.hadoop.hbase.HBaseStorage.getNext(HBaseStorage.java:452)
         at
org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.PigRecordReader.nextKeyValue(PigRecordReader.java:194)
         at
org.apache.hadoop.mapred.MapTask$NewTrackingRecordReader.nextKeyValue(MapTask.java:532)
         at
org.apache.hadoop.mapreduce.MapContext.nextKeyValue(MapContext.java:67)
         at org.apache.hadoop.mapreduce.Mapper.run(Mapper.java:143)
         at
org.apache.hadoop.mapred.MapTask.runNewMapper(MapTask.java:764)
         at org.apache.hadoop.mapred.MapTask.run(MapTask.java:370)
         at org.apache.hadoop.mapred.Child$4.run(Child.java:255)
         at java.security.AccessController.doPrivileged(Native Method)
         at javax.security.auth.Subject.doAs(Subject.java:396)
         at
org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1121)
         at org.apache.hadoop.mapred.Child.main(Child.java:249)

Region server:

2012-11-21 14:45:55,199 ERROR
org.apache.hadoop.hbase.regionserver.HRegionServer:
org.apache.hadoop.hbase.regionserver.LeaseException: lease
'4537659031468873643' does not exist
         at
org.apache.hadoop.hbase.regionserver.Leases.removeLease(Leases.java:231)
         at
org.apache.hadoop.hbase.regionserver.HRegionServer.next(HRegionServer.java:2117)
         at sun.reflect.GeneratedMethodAccessor25.invoke(Unknown Source)
         at
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
         at
org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1326)

2012-11-21 14:45:57,320 WARN org.apache.hadoop.ipc.HBaseServer:
(responseTooSlow):
{"processingtimems":63895,"call":"next(4537659031468873643, 512),
rpc version=1, client version=29,
methodsFingerPrint=54742778","client":"10.124.45.132:19289","starttimems":13535090\
93424,"queuetimems":0,"class":"HRegionServer","responsesize":6,"method":"next"}
2012-11-21 14:45:57,320 WARN org.apache.hadoop.ipc.HBaseServer: IPC
Server Responder, call next(45376

Yes we put and get small amount of data.
We already increased handler count to 30, maybe it is not enough...
We will try this.
Le 21/11/12 05:53, Alok Singh a �crit :
> Do your PUTs and GETs have small amounts of data? If yes, then you can
> increase the number of handlers.
> We have a 8-node cluster on 0.92.1, and these are some of the setting
> we changed from 0.90.4
>
> hbase.regionserver.handler.count = 150
> hbase.hregion.max.filesize=2147483648 (2GB)
>
> The regions servers are run with a 16GB heap (-Xmx16000M)
>
> With these settings, at peak we can handle ~2K concurrent clients.
>
> Alok
>
> On Tue, Nov 20, 2012 at 8:21 AM, Vincent Barat <[EMAIL PROTECTED]> wrote:
>> Hi,
>>
>> We have changed some parameters on our 16(!) region servers : 1GB more -Xmx,
>> more rpc handler (from 10 to 30) longer timeout, but nothing seems to
>> improve the response time:
>>
>> - Scans with HBase 0.92  are x3 SLOWER than with HBase 0.90.3
>> - A lot of simultaneous gets lead to a huge slow down of batch put & ramdom
>> read response time
>>
>> ... despite the fact that our RS CPU load is really low (10%)
>>
>> Note: we have not (yet) activated MSlabs, nor direct read on HDFS.
>>
>> Any idea please ? I'm really stuck on that issue.
>>
>> Best regards,
>>
>> Le 16/11/12 20:55, Vincent Barat a �crit :
>>> Hi,
>>>
>>> Right now (and previously with 0.90.3) we were using the default value
>>> (10).
>>> We are trying right now to increase to 30 to see if it is better.
>>>
>>> Thanks for your concern
>>>
>>> Le 16/11/12 18:13, Ted Yu a �crit :
>>>> Vincent:
>>>> What's the value for hbase.regionserver.handler.count ?
>>>>
>>>> I assume you keep the same value as that from 0.90.3
>>>>
>>>> Thanks
>>>>
>>>> On Fri, Nov 16, 2012 at 8:14 AM, Vincent
>>>> Barat<[EMAIL PROTECTED]>wrote:
>>>>
>>>>> Le 16/11/12 01:56, Stack a �crit :
>>>>>
>>>>>    On Thu, Nov 15, 2012 at 5:21 AM, Guillaume Perrot<[EMAIL PROTECTED]>
>>>>>> wrote:
>>>>>>
>>>>>>> It happens when several tables are being compacted and/or when there
>>>>>>> is
>>>>>>> several scanners running.
>>>>>>>
>>>>>> It happens for a particular region?  Anything you can tell about the
>>>>>> server looking in your cluster monitoring?  Is it running hot?  What
>>>>>> do the hbase regionserver stats in UI say?  Anything interesting about
>>>>>> compaction queues or requests?
>>>>>>
>>>>> Hi, thanks for your answser Stack. I will take the lead on that thread
>>>>> from now on.
>>>>>
>>>>> It does not happens on any particular region. Actually, things get
>>>>> better
>>>>> now since compactions have been performed on all tables and have been
>>>>> stopped.
>>>>>
>>>>> Nevertheless, we face a dramatic decrease of performances (especially on
>>>>> random gets) of the overall cluster:
>>>>>
>>>>> Despite the fact we double our number of region servers (from 8 to 16)
>>>>> and
>>>>> despite the fact that these region server CPU load are just about 10% to
>>>>> 30%, performances are really bad : very often an light increase of
>>>>> request
>>>>> lead to a clients locked on request, very long response time. It looks
>>>>> like
>>>>> a contention / deadlock somewhere in the HBase client and C code.
>>>>>
>>>>>
>>>>>
>>>>>> If you look at the thread dump all handlers are occupied serving
>>>>>> requests?  These timedout requests couldn't get into the server?
>>>>>>
>>>>> We will investigate on that and report to you.
>>>>>
>>>>>
>>>>>    Before the timeouts, we observe an increasing CPU load on a single
>>>>> region
>>>>>>> server and if we add region servers and wait for rebalancing, we
>>>>>>> always
>>>>>>> have the same region server causing problems like these:
>>>>>>>
>>>>>>> 2012-11-14 20:47:08,443 WARN org.apache.hadoop.ipc.**HBaseServer: IPC
>>>>>>> Server Responder, call
>>>>>>> multi(org.apache.hadoop.hbase.**client.MultiAction@2c3da1aa), rpc
>>>>>>> version=1, client version=29, methodsFingerPrint=54742778 from
>>>>>>> <ip>:45334: output error
>>>>>>> 2012-11-14 20:47:08,443 WARN org.apache.hadoop.ipc.**HBaseServer: IPC