David - the plan is to synthesize the waiting state. Exactly how is not yet certain.
On Wednesday, October 15, 2014, Maxim Khutornenko <ma...@apache.org> wrote: > It is certainly possible to add new state or a status message but I > don't think it's a blocker for the first iteration. Provided there is > enough demand a state/message could be synthesized during the 'get' > call based on the volatile state. > > On Wed, Oct 15, 2014 at 6:36 PM, David McLaughlin <da...@dmclaughlin.com > <javascript:;>> wrote: > > +1 for pause being explicit RPC pauses, but does it really add complexity > > to just add a new state (WAITING?) when no heartbeat is sent? Not being > > able to see that an update was blocked because of a lack of heartbeat > seems > > like a missing feature. > > > > On Wed, Oct 15, 2014 at 5:12 PM, Maxim Khutornenko <ma...@apache.org > <javascript:;>> wrote: > > > >> +1. Updated the doc: > >> > >> > https://github.com/maxim111333/incubator-aurora/blob/hb_doc/docs/update-heartbeat.md > >> > >> On Wed, Oct 15, 2014 at 5:09 PM, Bill Farner <wfar...@apache.org > <javascript:;>> wrote: > >> > +1 to the scheduler not proceeding on an update when heartbeats are > >> absent, > >> > and requiring the heartbeat service to explicitly call pauseJobUpdate > >> when > >> > it detects problems. > >> > > >> > -=Bill > >> > > >> > On Wed, Oct 15, 2014 at 4:59 PM, Kevin Sweeney > >> <kswee...@twitter.com.invalid > >> >> wrote: > >> > > >> >> Chatted with Maxim and Bill, I think we figured it out > >> >> > >> >> I think the confusion stems from the fact that there are two types of > >> >> pauses in this system, explicit, persisted pauses generated by the > >> >> pauseJobUpdate RPC and implicit, volatile pauses caused due to the > >> absence > >> >> of a sufficiently fresh heartbeat (such as in the case of a network > >> >> partition). > >> >> > >> >> In case a monitoring service detects a problem it should call the > >> explicit > >> >> pauseJobUpdate RPC, which will cause a state change that requires an > >> >> explicit resumeJobUpdate RPC to resume. That feature already exists. > >> >> > >> >> But, we need one more thing to make this reliable - heartbeats to > >> protect > >> >> against network partitions between the scheduler and the monitoring > >> >> service. These can be volatile and lightweight - the scheduler just > >> checks > >> >> for a sufficiently fresh heartbeat before it performs an update > action, > >> and > >> >> if none is present it simply refuses to perform the action. If the > >> >> partition heals a new heartbeat will arrive (if the update being > >> monitored > >> >> should still be allowed to proceed) and the scheduler will allow the > >> update > >> >> to proceed. > >> >> > >> >> > >> >> On Wed, Oct 15, 2014 at 11:56 AM, Bill Farner <wfar...@apache.org > <javascript:;>> > >> wrote: > >> >> > >> >> > I think we should assess that after building the rest of the > feature. > >> >> IIUC > >> >> > the rest of the code doesn't care if the update is initially > paused. > >> >> > > >> >> > -=Bill > >> >> > > >> >> > On Wed, Oct 15, 2014 at 11:50 AM, Maxim Khutornenko < > ma...@apache.org <javascript:;> > >> > > >> >> > wrote: > >> >> > > >> >> > > Can we get a consensus here? Looks like the only sticky point > left > >> is > >> >> > > around starting an update in paused vs. non-paused state. I can > >> argue > >> >> > > either way as it's easy to add later if needed. > >> >> > > > >> >> > > On Tue, Oct 14, 2014 at 1:03 PM, Bill Farner <wfar...@apache.org > <javascript:;>> > >> >> wrote: > >> >> > > > I'm not arguing against the merits of the approach. Just > feeling > >> out > >> >> > > > whether that should be done _after_ the rest of the heartbeat > >> >> support. > >> >> > > > Seems like it can be cleanly added at the end to get something > >> usable > >> >> > > > earlier. > >> >> > > > > >> >> > > > -=Bill > >> >> > > > > >> >> > > > On Tue, Oct 14, 2014 at 12:38 PM, Kevin Sweeney < > >> kevi...@apache.org <javascript:;>> > >> >> > > wrote: > >> >> > > > > >> >> > > >> I'm +1 for using lack of heartbeats as a uniform > >> >> unknown-or-unhealthy > >> >> > > >> signal, and punting on a more complex NACK signal (which we'd > >> have > >> >> to > >> >> > > >> reliably persist). > >> >> > > >> > >> >> > > >> I think the only disagreement in this thread is whether the > >> default > >> >> > > state > >> >> > > >> for a new update should be running or waiting-for-heartbeat. I > >> think > >> >> > > >> waiting for a heartbeat is not only a more correct > implementation > >> >> (no > >> >> > > risk > >> >> > > >> of acting after a failover but before the heartbeat timeout) > but > >> >> > > simpler to > >> >> > > >> implement (initialize the PulseMonitor data structure as empty > >> >> rather > >> >> > > than > >> >> > > >> with a synthetic heartbeat). > >> >> > > >> > >> >> > > >> From an API consumer perspective the sequence is: > >> >> > > >> > >> >> > > >> 1. API client sends a startUpdate RPC to the scheduler > >> >> > > >> 2. API client receives an OK response, then arranges for > >> something > >> >> to > >> >> > > call > >> >> > > >> heartbeat with that updateId on some interval > >> >> > > >> 3. Whatever is supposed to send heartbeats sends one > immediately, > >> >> then > >> >> > > >> starts sending them on some smaller interval > >> >> > > >> > >> >> > > >> Waiting for the first heartbeat ensures that this sequence has > >> been > >> >> > > >> completed successfully, while not waiting for it only ensure > that > >> >> > step 1 > >> >> > > >> has happened. > >> >> > > >> > >> >> > > >> > >> >> > > >> On Tue, Oct 14, 2014 at 12:18 PM, Bill Farner < > >> wfar...@apache.org <javascript:;>> > >> >> > > wrote: > >> >> > > >> > >> >> > > >> > Wait - simpler solution than what? We're talking about not > >> doing > >> >> > > either. > >> >> > > >> > > >> >> > > >> > -=Bill > >> >> > > >> > > >> >> > > >> > On Tue, Oct 14, 2014 at 12:16 PM, Kevin Sweeney < > >> >> kevi...@apache.org <javascript:;> > >> >> > > > >> >> > > >> > wrote: > >> >> > > >> > > >> >> > > >> > > I think waiting for the first heartbeat before taking any > >> action > >> >> > is > >> >> > > the > >> >> > > >> > > simpler solution here as it allows the implementation to > be > >> >> > entirely > >> >> > > >> > > soft-state and still catches the bugs I described. > >> >> > > >> > > > >> >> > > >> > > The implementation is just PulseMonitorImpl<UpdateId> - > >> >> heartbeat > >> >> > > calls > >> >> > > >> > > pulse and mutation operations check isAlive. I think the > code > >> >> > might > >> >> > > >> > > actually work as-is. > >> >> > > >> > > > >> >> > > >> > > On Tue, Oct 14, 2014 at 12:11 PM, Maxim Khutornenko < > >> >> > > ma...@apache.org <javascript:;>> > >> >> > > >> > > wrote: > >> >> > > >> > > > >> >> > > >> > > > Pausing update on creation seems like a logical approach > >> when > >> >> > > dealing > >> >> > > >> > > > with inverted dependency model. I.e. updater is happy to > >> act > >> >> as > >> >> > > long > >> >> > > >> > > > as it's greenlighted by the external signal. It's also > >> aligned > >> >> > > with a > >> >> > > >> > > > failover experience where coordinated updates are > >> rehydrated > >> >> in > >> >> > > >> paused > >> >> > > >> > > > state waiting for HB awakening. That said, I am OK > punting > >> it > >> >> > for > >> >> > > the > >> >> > > >> > > > sake of simplicity for now. > >> >> > > >> > > > > >> >> > > >> > > > Kevin? > >> >> > > >> > > > > >> >> > > >> > > > On Tue, Oct 14, 2014 at 12:05 PM, Bill Farner < > >> >> > wfar...@apache.org <javascript:;> > >> >> > > > > >> >> > > >> > > wrote: > >> >> > > >> > > > > If the goal is to reduce complexity now and add > features > >> >> > later, > >> >> > > why > >> >> > > >> > not > >> >> > > >> > > > > nuke both for now - kick off the update right away, > and > >> let > >> >> > > lack of > >> >> > > >> > > > > heartbeats serve as a uniform "unknown or unhealthy" > >> signal? > >> >> > > >> > > > > > >> >> > > >> > > > > -=Bill > >> >> > > >> > > > > > >> >> > > >> > > > > On Mon, Oct 13, 2014 at 5:25 PM, Maxim Khutornenko < > >> >> > > >> ma...@apache.org <javascript:;> > >> >> > > >> > > > >> >> > > >> > > > wrote: > >> >> > > >> > > > > > >> >> > > >> > > > >> I am still +1 on the idea to have default paused > state > >> on > >> >> > > >> creation. > >> >> > > >> > I > >> >> > > >> > > > >> think we could still differentiate between initially > >> paused > >> >> > and > >> >> > > >> > timed > >> >> > > >> > > > >> out states internally by looking at pause reason. > It's > >> >> quite > >> >> > > >> > different > >> >> > > >> > > > >> if we want to store explicit NACK reasons from the > >> external > >> >> > > >> service > >> >> > > >> > > > >> though. That would require persistence and a bit more > >> >> > > complicated > >> >> > > >> > > > >> logic. > >> >> > > >> > > > >> > >> >> > > >> > > > >> On Mon, Oct 13, 2014 at 5:15 PM, Kevin Sweeney < > >> >> > > >> kevi...@apache.org <javascript:;>> > >> >> > > >> > > > wrote: > >> >> > > >> > > > >> > I like the idea of implementing this scheduler-side > >> >> purely > >> >> > > >> through > >> >> > > >> > > > >> volatile > >> >> > > >> > > > >> > state, but the lack of feedback (generic vs > specific > >> >> error > >> >> > > >> > messages > >> >> > > >> > > > when > >> >> > > >> > > > >> an > >> >> > > >> > > > >> > update is paused) leaves something to be desired. > >> Maybe > >> >> we > >> >> > > can > >> >> > > >> > > address > >> >> > > >> > > > >> that > >> >> > > >> > > > >> > with a metadata field in the initial call to > >> startUpdate > >> >> > > (with > >> >> > > >> an > >> >> > > >> > > > >> optional > >> >> > > >> > > > >> > link to a page where one can get more rich > information > >> >> > about > >> >> > > the > >> >> > > >> > > > state of > >> >> > > >> > > > >> > the monitor sending/not sending heartbeats). > >> >> > > >> > > > >> > > >> >> > > >> > > > >> > The main drawback is that we may have to wait a > >> maximum > >> >> of > >> >> > > one > >> >> > > >> > > > heartbeat > >> >> > > >> > > > >> > interval to find out that an update should be > paused. > >> >> > > >> > > > >> > > >> >> > > >> > > > >> > On Mon, Oct 13, 2014 at 4:55 PM, Maxim Khutornenko > < > >> >> > > >> > > ma...@apache.org <javascript:;>> > >> >> > > >> > > > >> wrote: > >> >> > > >> > > > >> > > >> >> > > >> > > > >> >> The main reason I preferred the lack-of-ACK > approach > >> >> over > >> >> > an > >> >> > > >> > > explicit > >> >> > > >> > > > >> >> NACK one is simplicity. As Joshua pointed out > there > >> is > >> >> > more > >> >> > > >> state > >> >> > > >> > > to > >> >> > > >> > > > >> >> handle in that case. The lack-of-ACK model can be > >> >> > completely > >> >> > > >> > > > >> >> implemented in volatile memory sidestepping the > >> >> persistent > >> >> > > >> > storage > >> >> > > >> > > > >> >> entirely. With the NACK we would need to reliably > >> >> persist > >> >> > > >> > external > >> >> > > >> > > > >> >> service call reasons to survive scheduler > failovers. > >> >> Not a > >> >> > > huge > >> >> > > >> > > > >> >> challenge but something to keep in mind. > >> >> > > >> > > > >> >> > >> >> > > >> > > > >> >> I still think the simplicity/reliability tradeoff > is > >> >> > > acceptable > >> >> > > >> > > here > >> >> > > >> > > > >> >> if we rely on external service to abort > heartbeats in > >> >> case > >> >> > > of a > >> >> > > >> > > > health > >> >> > > >> > > > >> >> alert fired. This can be explicitly documented as > an > >> >> > > external > >> >> > > >> > > > >> >> integration requirement. However, If the consensus > >> is to > >> >> > go > >> >> > > a > >> >> > > >> > more > >> >> > > >> > > > >> >> reliable (though more complicated) NACK route I am > >> happy > >> >> > to > >> >> > > >> > > > reconsider > >> >> > > >> > > > >> >> the current proposal. > >> >> > > >> > > > >> >> > >> >> > > >> > > > >> >> On Mon, Oct 13, 2014 at 3:50 PM, Joshua Cohen < > >> >> > > >> > > > jco...@twopensource.com <javascript:;>> > >> >> > > >> > > > >> >> wrote: > >> >> > > >> > > > >> >> > "The heratbeatJobUpdate RPC serves as an ACK, > but > >> we > >> >> > don't > >> >> > > >> > have a > >> >> > > >> > > > >> NACK. > >> >> > > >> > > > >> >> If > >> >> > > >> > > > >> >> > we are going to let lack-of-ACK serve as the > NACK, > >> i > >> >> > don't > >> >> > > >> > think > >> >> > > >> > > > it's > >> >> > > >> > > > >> >> safe > >> >> > > >> > > > >> >> > to resume when we receive another ACK. In other > >> >> words, > >> >> > a > >> >> > > >> > service > >> >> > > >> > > > >> >> toggling > >> >> > > >> > > > >> >> > unhealthy might not be deemed safe to proceed." > >> >> > > >> > > > >> >> > > >> >> > > >> > > > >> >> > Lack-of-ACK is the scenario where connectivity > >> between > >> >> > the > >> >> > > >> > > monitor > >> >> > > >> > > > and > >> >> > > >> > > > >> >> the > >> >> > > >> > > > >> >> > scheduler is unavailable. Shouldn't the NACK > >> scenario > >> >> > > >> > (everything > >> >> > > >> > > > is > >> >> > > >> > > > >> not > >> >> > > >> > > > >> >> > ok!) be handled by the monitoring service > >> triggering > >> >> an > >> >> > > >> > explicit > >> >> > > >> > > > >> pause? > >> >> > > >> > > > >> >> > I.e. section 2 should be updated to say > "External > >> >> > service > >> >> > > >> > detects > >> >> > > >> > > > >> service > >> >> > > >> > > > >> >> > health problems and pauses the update" and > section > >> 4 > >> >> > > becomes > >> >> > > >> > the > >> >> > > >> > > > >> current > >> >> > > >> > > > >> >> > section 2 (i.e. "Should a heartbeat not be > received > >> >> the > >> >> > > >> > scheduler > >> >> > > >> > > > >> pauses > >> >> > > >> > > > >> >> > the update."). > >> >> > > >> > > > >> >> > > >> >> > > >> > > > >> >> > I agree that it's unsafe to to resume updates > after > >> >> > > >> receiving a > >> >> > > >> > > > >> heartbeat > >> >> > > >> > > > >> >> > after previously pausing due to a missed > >> heartbeat. In > >> >> > > that > >> >> > > >> > > > scenario > >> >> > > >> > > > >> I'd > >> >> > > >> > > > >> >> > think we'd want an explicit resumeJobUpdate. If > the > >> >> > > scenario > >> >> > > >> > > we're > >> >> > > >> > > > >> trying > >> >> > > >> > > > >> >> > to handle is *never* received a heartbeat, > that's a > >> >> > > separate > >> >> > > >> > > > matter, > >> >> > > >> > > > >> in > >> >> > > >> > > > >> >> > that case unpausing upon receiving the first > >> heartbeat > >> >> > > would > >> >> > > >> > make > >> >> > > >> > > > >> sense, > >> >> > > >> > > > >> >> > but it feels like that complicates things quite > a > >> bit > >> >> > > (now we > >> >> > > >> > > need > >> >> > > >> > > > to > >> >> > > >> > > > >> >> > differentiate between heartbeat #1 and hearbeat > >> #N). > >> >> > > >> > > > >> >> > > >> >> > > >> > > > >> >> > On Mon, Oct 13, 2014 at 2:50 PM, Bill Farner < > >> >> > > >> > wfar...@apache.org <javascript:;> > >> >> > > >> > > > > >> >> > > >> > > > >> wrote: > >> >> > > >> > > > >> >> > > >> >> > > >> > > > >> >> >> What is the guidance for deploying while the > >> >> heartbeat > >> >> > > >> service > >> >> > > >> > > is > >> >> > > >> > > > >> >> broken? > >> >> > > >> > > > >> >> >> I think i know the answer, but it's important > to > >> >> spell > >> >> > > out. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > Create a new coordinated job update in a > paused > >> >> > > >> > > > >> (ROLL_FORWARD_PAUSED) > >> >> > > >> > > > >> >> >> > state to avoid any progress until the first > >> >> heartbeat > >> >> > > call > >> >> > > >> > > > arrives. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> I'm not sold on this being ultimately > >> beneficial. In > >> >> > the > >> >> > > >> > worst > >> >> > > >> > > > case, > >> >> > > >> > > > >> >> >> impact is still limited by the health check > >> >> threshold. > >> >> > > >> Seems > >> >> > > >> > > like > >> >> > > >> > > > >> >> >> premature optimization at best, and an odd one > if > >> we > >> >> > > proceed > >> >> > > >> > > > without > >> >> > > >> > > > >> a > >> >> > > >> > > > >> >> >> 'NACK' signal via the heartbeatJobUpdate RPC. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> Allow resuming of the > paused-due-to-no-heartbeat > >> >> update > >> >> > > via > >> >> > > >> a > >> >> > > >> > > > >> >> >> > resumeJobUpdate call. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> Are heartbeats required while rolling back? If > >> so, > >> >> > that > >> >> > > >> might > >> >> > > >> > > > impact > >> >> > > >> > > > >> >> the > >> >> > > >> > > > >> >> >> design here and in other places. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> Allow resuming of the > paused-due-to-no-heartbeat > >> >> update > >> >> > > via > >> >> > > >> a > >> >> > > >> > > > fresh > >> >> > > >> > > > >> >> >> > heartbeatJobUpdate call. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> The heratbeatJobUpdate RPC serves as an ACK, > but > >> we > >> >> > don't > >> >> > > >> > have a > >> >> > > >> > > > >> NACK. > >> >> > > >> > > > >> >> If > >> >> > > >> > > > >> >> >> we are going to let lack-of-ACK serve as the > >> NACK, i > >> >> > > don't > >> >> > > >> > think > >> >> > > >> > > > it's > >> >> > > >> > > > >> >> safe > >> >> > > >> > > > >> >> >> to resume when we receive another ACK. In > other > >> >> > words, a > >> >> > > >> > > service > >> >> > > >> > > > >> >> toggling > >> >> > > >> > > > >> >> >> unhealthy might not be deemed safe to proceed. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> Perhaps just sending OK (or a NOOP equivalent) > in > >> >> case > >> >> > > of a > >> >> > > >> > > > >> user-paused > >> >> > > >> > > > >> >> job > >> >> > > >> > > > >> >> >> > update would make more sense as there is > nothing > >> >> > > >> monitoring > >> >> > > >> > > > service > >> >> > > >> > > > >> >> could > >> >> > > >> > > > >> >> >> > do in that case. This should work fine with > >> >> > > pause/resume > >> >> > > >> > > > >> >> -aware/-agnostic > >> >> > > >> > > > >> >> >> > monitoring service implementation. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> This seems reasonable to me - heartbeats for a > >> paused > >> >> > > update > >> >> > > >> > > > should > >> >> > > >> > > > >> not > >> >> > > >> > > > >> >> >> pose a risk, but can be safely ignored. > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> -=Bill > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> On Mon, Oct 13, 2014 at 12:48 PM, Maxim > >> Khutornenko < > >> >> > > >> > > > >> ma...@apache.org <javascript:;>> > >> >> > > >> > > > >> >> >> wrote: > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> >> > Agreed. That would be a logical > generalization > >> of > >> >> the > >> >> > > post > >> >> > > >> > > > failover > >> >> > > >> > > > >> >> >> > behavior. > >> >> > > >> > > > >> >> >> > > >> >> > > >> > > > >> >> >> > I have updated the above document with the > >> >> following > >> >> > > >> > changes: > >> >> > > >> > > > >> >> >> > - Reply with PAUSED any time a job was > paused by > >> >> > user; > >> >> > > >> > > > >> >> >> > - Start in paused state by default. > >> >> > > >> > > > >> >> >> > > >> >> > > >> > > > >> >> >> > On Mon, Oct 13, 2014 at 11:32 AM, Kevin > Sweeney > >> < > >> >> > > >> > > > >> kevi...@apache.org <javascript:;>> > >> >> > > >> > > > >> >> >> > wrote: > >> >> > > >> > > > >> >> >> > > The doc mentioned that the scheduler will > >> start > >> >> an > >> >> > > >> update > >> >> > > >> > > > >> subject to > >> >> > > >> > > > >> >> >> the > >> >> > > >> > > > >> >> >> > > heartbeat countdown, and if it doesn't > >> receive a > >> >> > > >> heartbeat > >> >> > > >> > > it > >> >> > > >> > > > >> will > >> >> > > >> > > > >> >> >> pause > >> >> > > >> > > > >> >> >> > > the update. Why not start with the update > >> >> > > >> > > > >> >> paused-due-to-no-heartbeat to > >> >> > > >> > > > >> >> >> > > fail-fast any connectivity issues between > the > >> >> > service > >> >> > > >> > > > providing > >> >> > > >> > > > >> the > >> >> > > >> > > > >> >> >> > > heartbeats and the scheduler? > >> >> > > >> > > > >> >> >> > > > >> >> > > >> > > > >> >> >> > > On Fri, Oct 10, 2014 at 12:47 PM, Maxim > >> >> > Khutornenko < > >> >> > > >> > > > >> >> ma...@apache.org <javascript:;>> > >> >> > > >> > > > >> >> >> > > wrote: > >> >> > > >> > > > >> >> >> > > > >> >> > > >> > > > >> >> >> > >> Hi all, > >> >> > > >> > > > >> >> >> > >> > >> >> > > >> > > > >> >> >> > >> We are proposing a new feature for the > >> scheduler > >> >> > > >> updater, > >> >> > > >> > > > which > >> >> > > >> > > > >> you > >> >> > > >> > > > >> >> >> > >> may find helpful. > >> >> > > >> > > > >> >> >> > >> > >> >> > > >> > > > >> >> >> > >> I have posed a brief feature summary here: > >> >> > > >> > > > >> >> >> > >> > >> >> > > >> > > > >> >> >> > >> > >> >> > > >> > > > >> >> >> > > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> > >> >> > > >> > > > >> > >> >> > > >> > > > > >> >> > > >> > > > >> >> > > >> > > >> >> > > >> > >> >> > > > >> >> > > >> >> > >> > https://github.com/maxim111333/incubator-aurora/blob/hb_doc/docs/update-heartbeat.md > >> >> > > >> > > > >> >> >> > >> > >> >> > > >> > > > >> >> >> > >> Please, reply with your > >> >> > feedback/concerns/comments. > >> >> > > >> > > > >> >> >> > >> > >> >> > > >> > > > >> >> >> > >> Thanks, > >> >> > > >> > > > >> >> >> > >> Maxim > >> >> > > >> > > > >> >> >> > >> > >> >> > > >> > > > >> >> >> > > >> >> > > >> > > > >> >> >> > >> >> > > >> > > > >> >> > >> >> > > >> > > > >> > >> >> > > >> > > > > >> >> > > >> > > > >> >> > > >> > > >> >> > > >> > >> >> > > > >> >> > > >> >> > >> >> > >> >> > >> >> -- > >> >> Kevin Sweeney > >> >> @kts > >> >> > >> > -- -=Bill
