Mailing-List: contact user-help@zookeeper.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@zookeeper.apache.org
Received-SPF: pass (athena.apache.org: domain of Camille.Fournier@gs.com
 designates 204.4.187.100 as permitted sender)
From: "Fournier, Camille F. [Tech]" <Camille.Fournier@gs.com>
To: "'user@zookeeper.apache.org'" <user@zookeeper.apache.org>
Date: Fri, 11 Feb 2011 18:00:21 -0500
Subject: RE: tickTime and sessionTimeout
Thread-Topic: tickTime and sessionTimeout
Thread-Index: AcvKOpPuuhI8hAR9RkSgIV1TLfzJiQAAG02g
Message-ID: 
 <69D3016305F9084FBD2C4A0DF189BD5C16B7F384FD@GSCMAMP02EX.firmwide.corp.gs.com>
References: 
 <6642FC1CAF133548AA8FDF497C547F0A23C0C5265B@NYWEXMBX2126.msad.ms.com>
 <4D548CC9.6090102@yahoo-inc.com>
 <AANLkTimpodJPZ9j_GY5Q8qLxLkQUk_=brsaz2C6jmj4D@mail.gmail.com>
 <AANLkTinj6s5D+Bg6azG8yTju_RLEOqxNgoYURHqJeD+H@mail.gmail.com>
 <AANLkTi=_-VF5fWd-0+dqj3TbGu4=W+ks2U68fzgqye2_@mail.gmail.com>
In-Reply-To: <AANLkTi=_-VF5fWd-0+dqj3TbGu4=W+ks2U68fzgqye2_@mail.gmail.com>
Accept-Language: en-US
Content-Language: en-US
acceptlanguage: en-US
Content-Type: text/plain; charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

What is your ZooKeeper setup here? And do you continue to see this issue if=
 you increase your session timeout?

C

-----Original Message-----
From: Nick Patania [mailto:Nicholas.Patania@morganstanley.com]=20
Sent: Friday, February 11, 2011 5:24 PM
To: user@zookeeper.apache.org
Subject: Re: tickTime and sessionTimeout

Patrick, thanks for your input.

I have rerun the test several times now while logging GC on the server
and running ping from CLIENT_1:

  - No GC happens on the server during the period of interest (a
couple of young generation runs happen before I kill HOST_0, and they
complete in under 3ms).
  - Round trip times for ping from CLIENT_1 are consistently under
250us throughout.

Regarding client GC -- I can consistently reproduce this using a C
client.  Regarding the theory of swapping on CLIENT_1 -- if that were
the cause, the problem wouldn't be 100% reproducible.  I also looked
through the client log for SESSION_1 -- I see "Got ping response ...
after 1ms" repeatedly, followed by "Client session timed out, have not
heard from server in 666ms"...

On Fri, Feb 11, 2011 at 1:46 PM, Patrick Hunt <phunt@apache.org> wrote:
> Those are pretty short timeouts, many sources of delay could be
> causing this. Network jitter/latency, GC/swap (server or client), IO
> write latency, etc... See if any of this might be your issue:
> https://cwiki.apache.org/confluence/display/ZOOKEEPER/Troubleshooting
>
> I can clearly see this sequence in your log for session1:
>
> ---
> 2011-02-11 14:18:52,672 - =A0sessionid:SESSION_1 type:ping
>
> 2011-02-11 14:18:54,502 - Expiring session SESSION_1, timeout of 1000ms e=
xceeded
>
> 2011-02-11 14:18:55,011 - Processing request:: sessionid:SESSION_1 type:p=
ing
> ---
>
> from the looks of it session 1 doesn't send a ping to the server for
> ~2.5 seconds, as a result it's expired.
>
> You should also look at your session 1 client log and see what it's
> view of the world is like. (is it gc/swapping?). Use the "stat" 4
> letter word to see the server's request processing latency, see if
> that's high (higer than the timeout is bad news). Again, checkout the
> troubleshooting guide.
>
> Patrick
>
> ps please use pastebin or attachment, otw the formatting of wrecked
> and it's harder to read the log
>
> On Fri, Feb 11, 2011 at 6:41 AM, Nick Patania
> <Nicholas.Patania@morganstanley.com> wrote:
>> This is the portion that seems relevant. =A0For readability, I replaced
>> the host and session for the host that I kill with HOST_0 and
>> SESSION_0 (I expect these to timeout). =A0The client that should be
>> healthy is HOST_1 and SESSION_1.
>>
>>
>> 2011-02-11 14:18:51,901 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@78] - Processing request::
>> sessionid:SESSION_0 type:ping cxid:0xfffffffffffffffe
>> zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:51,901 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@160] - sessionid:SESSION_0
>> type:ping cxid:0xfffffffffffffffe zxid:0xfffffffffffffffe
>> txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:52,005 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@78] - Processing request::
>> sessionid:SESSION_1 type:ping cxid:0xfffffffffffffffe
>> zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:52,005 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@160] - sessionid:SESSION_1
>> type:ping cxid:0xfffffffffffffffe zxid:0xfffffffffffffffe
>> txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:52,339 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@78] - Processing request::
>> sessionid:SESSION_1 type:ping cxid:0xfffffffffffffffe
>> zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:52,339 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@160] - sessionid:SESSION_1
>> type:ping cxid:0xfffffffffffffffe zxid:0xfffffffffffffffe
>> txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:52,672 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@78] - Processing request::
>> sessionid:SESSION_1 type:ping cxid:0xfffffffffffffffe
>> zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:52,672 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@160] - sessionid:SESSION_1
>> type:ping cxid:0xfffffffffffffffe zxid:0xfffffffffffffffe
>> txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:53,002 - INFO =A0[SessionTracker:ZooKeeperServer@314] -
>> Expiring session SESSION_0, timeout of 1000ms exceeded
>> 2011-02-11 14:18:53,002 - INFO
>> [ProcessThread:-1:PrepRequestProcessor@387] - Processed session
>> termination for sessionid: SESSION_0
>> 2011-02-11 14:18:53,010 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@78] - Processing request::
>> sessionid:SESSION_0 type:closeSession cxid:0x0 zxid:0x103 txntype:-11
>> reqpath:n/a
>> 2011-02-11 14:18:53,010 - INFO =A0[SyncThread:0:NIOServerCnxn@1435] -
>> Closed socket connection for client /HOST_0:34618 which had sessionid
>> SESSION_0
>> 2011-02-11 14:18:54,502 - INFO =A0[SessionTracker:ZooKeeperServer@314] -
>> Expiring session SESSION_1, timeout of 1000ms exceeded
>> 2011-02-11 14:18:54,502 - INFO
>> [ProcessThread:-1:PrepRequestProcessor@387] - Processed session
>> termination for sessionid: SESSION_1
>> 2011-02-11 14:18:55,011 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@78] - Processing request::
>> sessionid:SESSION_1 type:ping cxid:0xfffffffffffffffe
>> zxid:0xfffffffffffffffe txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:55,011 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@160] - sessionid:SESSION_1
>> type:ping cxid:0xfffffffffffffffe zxid:0xfffffffffffffffe
>> txntype:unknown reqpath:n/a
>> 2011-02-11 14:18:55,011 - INFO
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:NIOServerCnxn$Factory@251]
>> - Accepted socket connection from /HOST_1:40556
>> 2011-02-11 14:18:55,019 - DEBUG
>> [SyncThread:0:FinalRequestProcessor@78] - Processing request::
>> sessionid:SESSION_1 type:closeSession cxid:0x0 zxid:0x104 txntype:-11
>> reqpath:n/a
>> 2011-02-11 14:18:55,019 - DEBUG
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:ZooKeeperServer@590] -
>> Dropping request: No session with sessionid SESSION_1 exists, probably
>> expired and removed
>> 2011-02-11 14:18:55,019 - INFO =A0[SyncThread:0:NIOServerCnxn@1435] -
>> Closed socket connection for client /HOST_1:40555 which had sessionid
>> SESSION_1
>> 2011-02-11 14:18:55,020 - DEBUG [SyncThread:0:NIOServerCnxn@1451] -
>> ignoring exception during output shutdown
>> java.net.SocketException: Transport endpoint is not connected
>> =A0 =A0 =A0 =A0at sun.nio.ch.SocketChannelImpl.shutdown(Native Method)
>> =A0 =A0 =A0 =A0at sun.nio.ch.SocketChannelImpl.shutdownOutput(SocketChan=
nelImpl.java:651)
>> =A0 =A0 =A0 =A0at sun.nio.ch.SocketAdaptor.shutdownOutput(SocketAdaptor.=
java:368)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn.closeSock(NI=
OServerCnxn.java:1447)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn.close(NIOSer=
verCnxn.java:1412)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn$Factory.clos=
eSessionWithoutWakeup(NIOServerCnxn.java:343)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn$Factory.clos=
eSession(NIOServerCnxn.java:330)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.FinalRequestProcessor.proc=
essRequest(FinalRequestProcessor.java:133)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.SyncRequestProcessor.flush=
(SyncRequestProcessor.java:161)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.SyncRequestProcessor.run(S=
yncRequestProcessor.java:98)
>> 2011-02-11 14:18:55,021 - DEBUG [SyncThread:0:NIOServerCnxn@1459] -
>> ignoring exception during input shutdown
>> java.net.SocketException: Transport endpoint is not connected
>> =A0 =A0 =A0 =A0at sun.nio.ch.SocketChannelImpl.shutdown(Native Method)
>> =A0 =A0 =A0 =A0at sun.nio.ch.SocketChannelImpl.shutdownInput(SocketChann=
elImpl.java:640)
>> =A0 =A0 =A0 =A0at sun.nio.ch.SocketAdaptor.shutdownInput(SocketAdaptor.j=
ava:360)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn.closeSock(NI=
OServerCnxn.java:1455)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn.close(NIOSer=
verCnxn.java:1412)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn$Factory.clos=
eSessionWithoutWakeup(NIOServerCnxn.java:343)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn$Factory.clos=
eSession(NIOServerCnxn.java:330)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.FinalRequestProcessor.proc=
essRequest(FinalRequestProcessor.java:133)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.SyncRequestProcessor.flush=
(SyncRequestProcessor.java:161)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.SyncRequestProcessor.run(S=
yncRequestProcessor.java:98)
>> 2011-02-11 14:18:55,022 - WARN
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:NIOServerCnxn$Factory@272]
>> - Ignoring unexpected runtime exception
>> java.nio.channels.CancelledKeyException
>> =A0 =A0 =A0 =A0at sun.nio.ch.SelectionKeyImpl.ensureValid(SelectionKeyIm=
pl.java:55)
>> =A0 =A0 =A0 =A0at sun.nio.ch.SelectionKeyImpl.readyOps(SelectionKeyImpl.=
java:69)
>> =A0 =A0 =A0 =A0at org.apache.zookeeper.server.NIOServerCnxn$Factory.run(=
NIOServerCnxn.java:241)
>> 2011-02-11 14:18:55,023 - DEBUG
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:NIOServerCnxn@735] -
>> Session establishment request from client /HOST_1:40556 client's
>> lastZxid is 0x0
>> 2011-02-11 14:18:55,023 - INFO
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:NIOServerCnxn@770] - Client
>> attempting to renew session SESSION_1 at /HOST_1:40556
>> 2011-02-11 14:18:55,024 - INFO
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:NIOServerCnxn@1573] -
>> Invalid session SESSION_1 for client /HOST_1:40556, probably expired
>> 2011-02-11 14:18:55,025 - WARN
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:NIOServerCnxn@634] -
>> EndOfStreamException: Unable to read additional data from client
>> sessionid SESSION_1, likely client has closed socket
>> 2011-02-11 14:18:55,025 - INFO
>> [NIOServerCxn.Factory:0.0.0.0/0.0.0.0:4799:NIOServerCnxn@1435] -
>> Closed socket connection for client /HOST_1:40556 which had sessionid
>> SESSION_1
>>
>>
>> On Thu, Feb 10, 2011 at 8:11 PM, Benjamin Reed <breed@yahoo-inc.com> wro=
te:
>>> do you see anything in the server log?
>>>
>>> ben
>>>
>>> On 02/10/2011 03:16 PM, Patania, Nick wrote:
>>>>
>>>> Hello,
>>>>
>>>> I run the following test:
>>>>
>>>>
>>>> * =A0 =A0 =A0 =A0 Two clients connect to a zookeeper server; the tickT=
ime on the
>>>> server is 500, and the sessionTimeout on the client is 1000.
>>>>
>>>> * =A0 =A0 =A0 =A0 Kill the host running one of the clients.
>>>>
>>>> * =A0 =A0 =A0 =A0 The second client receives a session timeout.
>>>>
>>>> Is there any reason why this might happen?
>>>>
>>>> Thanks
>>>> Nick Patania
>>>>
>>>>
>>>> ----------------------------------------------------------------------=
----
>>>> NOTICE: Morgan Stanley is not acting as a municipal advisor and the
>>>> opinions or views contained herein are not intended to be, and do not
>>>> constitute, advice within the meaning of Section 975 of the Dodd-Frank=
 Wall
>>>> Street Reform and Consumer Protection Act. If you have received this
>>>> communication in error, please destroy all electronic and paper copies=
 and
>>>> notify the sender immediately. Mistransmission is not intended to waiv=
e
>>>> confidentiality or privilege. Morgan Stanley reserves the right, to th=
e
>>>> extent permitted under applicable law, to monitor electronic communica=
tions.
>>>> This message is subject to terms available at the following link:
>>>> http://www.morganstanley.com/disclaimers. If you cannot access these l=
inks,
>>>> please notify us by reply message and we will send the contents to you=
. By
>>>> messaging with Morgan Stanley you consent to the foregoing.
>>>
>>>
>>
>