Hi, On Tue, Mar 10, 2009 at 12:07 PM, Prasad Chakka <pra...@facebook.com> wrote:
> I use a thread specific storage to do something similar. Ie. I keep the > initialized session in the tss so new threads will not have it initialized. > Would that work here? > I am sorry you misunderstanded our meaning, we are talking about new threads with a new session state should be initialized. > > > The Thrift Interface handler is constructed just once for the lifetime of > the HiveServer. The session object is initialized inside this constructor. > The SessionState.start() is called only once (in the constructor) > > All connections/requests then go through the same handler object – but when > they run in worker threads – they don’t have a current session object for > that thread. > This the right thing I want to explain. > > > I think the solution here is to initialize TThreadPoolServer using a custom > implementation of TProcessorFactory. The getProcessor() call can return a > freshly constructed handler (with new SessionState etc.). This will work in > all scenarios I think. (btw – the same thread can serve different > connections – but from reading the code – a getProcessor() call will be made > for every connection) > > (see TThreadPoolServer.WorkerProcess and TThreadPoolServer.serve()) > This idea will work if the TProcessorFactory could caught the event server has already accepted a client, I think. > > > ------------------------------ > > *From:* Prasad Chakka [mailto:pra...@facebook.com <pra...@facebook.com>] > *Sent:* Monday, March 09, 2009 8:23 PM > *To:* hive-user@hadoop.apache.org > *Subject:* Re: thread cofinement session state > > I am assuming he is using the same code as MetaStore server. AFAIK, > TThreadPoolServer is supposed to use a new thread for each connection. > > ------------------------------ > > *From: *Joydeep Sen Sarma <jssa...@facebook.com> > *Reply-To: *<hive-user@hadoop.apache.org> > *Date: *Mon, 9 Mar 2009 20:16:22 -0700 > *To: *<hive-user@hadoop.apache.org> > *Subject: *RE: thread cofinement session state > > (also been reading up on this code a bit just now) > > That’s weird. It seems to be using TThreadPoolServer and that seems to just > service all requests from a single connection in one thread. (and uses the > same processor I assume that seems to initialize the session state in the > interface constructor) > > Are ur execute calls happening on the same connection? > > ------------------------------ > > > *From:* Min Zhou [mailto:coderp...@gmail.com <coderp...@gmail.com>] > *Sent:* Monday, March 09, 2009 8:03 PM > *To:* hive-user@hadoop.apache.org > *Subject:* thread cofinement session state > > Hi list, > I found each invoke of HiveServer's execute method run in different > threads. Those threads which execute a HSQL query(not a client connection > may execute several pieces of queries), have not their own session state. > when I call SessionState.get(), it will return null beacuse session state on > this thread hadnot been constructed before. see also fragment of > ExecDriver.java: > > public static String getRealFiles(Configuration conf) { > // fill in local files to be added to the task environment > SessionState ss = SessionState.get(); // return ss will get null !!! > ... > } > > Is it a bug? > > Thanks, > Min > -- > My research interests are distributed systems, parallel computing and > bytecode based virtual machine. > > http://coderplay.javaeye.com > > -- My research interests are distributed systems, parallel computing and bytecode based virtual machine. http://coderplay.javaeye.com
