Scheduling an asynchronous task to drop the index everywhere seems like it's adding a lot of complexity and potential for race conditions. Is it really worth optimizing memory usage in this edge case where we hit an exception updating an index? The objective of these changes is to fix a window where we are leaving the system in a corrupt state, I think we should do that in the least complicated way possible.
-Dan On Wed, Sep 20, 2017 at 3:54 PM, Swapnil Bawaskar <sbawas...@pivotal.io> wrote: > Thanks for the explanation Naba, please find my reply below: > 1. Debugging: If we log a warning, that should get noticed immediately, so > I don't think we need to worry about logs rolling. > 2. Performance for a single put: We can always schedule an async task to > drop the index. > > On Wed, Sep 20, 2017 at 3:49 PM Nabarun Nag <n...@apache.org> wrote: > > > Hi Swapnil, > > There were few factors we considered before going with just invalidating > > the index rather than destroying the index. > > 1. Debugging reasons : If the indexes were destroyed and logs roll over, > > and suddenly we see that indexes have disappeared, it will be tough to > > differentiate between whether the indexes were created improperly in the > > first place [/ restarts] or if a put corrupted it hence it was destroyed. > > In case of marking it invalid, we know for sure that a put has corrupted > > the index and prevent confusion for the user. > > > > 2. Performance perspective : We were worried that if a put corrupts > > multiple indexes and then that put is also responsible for destroying > those > > indexes may slow down the execution as it will have to acquire/release > > locks to destroy indexes [especially in case of PR indexes]. We were also > > worried about race conditions arising in that case. > > > > Regards > > Nabarun > > > > On Wed, Sep 20, 2017 at 2:59 PM Swapnil Bawaskar <sbawas...@pivotal.io> > > wrote: > > > > > Sorry for not reading this thread earlier, but I was wondering what is > > the > > > point of just invalidating the index and having it lie around if it is > > not > > > going to be used? > > > Can we just drop the index instead, and log a warning message to that > > > effect? This will free up the memory used by the index and will > > proactively > > > let the admin/user know what happened. > > > > > > On Wed, Sep 20, 2017 at 9:59 AM Nabarun Nag <n...@apache.org> wrote: > > > > > > > The PR #768 has been created for this issue and also GEODE-3520 has > > been > > > > changed to reflect this requirement. > > > > > > > > Regards > > > > Nabarun > > > > > > > > On Thu, Sep 14, 2017 at 5:29 PM Nabarun Nag <n...@apache.org> wrote: > > > > > > > > > Thanks you guys for the review. I will revert the GEODE-3520 ticket > > to > > > > > reflect that invalidate should happen for both synchronous and > > > > asynchronous > > > > > index maintenance. > > > > > Also, I will resend the PR which reflects the changes mentioned in > > the > > > > > ticket > > > > > > > > > > Regards > > > > > Nabarun Nag > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > On Thu, Sep 14, 2017 at 5:55 PM Anilkumar Gingade < > > aging...@pivotal.io > > > > > > > > > wrote: > > > > > > > > > >> Dan, you are right...Thanks to Jason, myself and Jason looked into > > the > > > > >> code > > > > >> to see if index is updated before the event/change is > saved/injected > > > > into > > > > >> the region...It looks like the index update are happening after > the > > > > region > > > > >> change/update is saved. Moving the index update before that is not > > an > > > > easy > > > > >> task... > > > > >> > > > > >> For time, when there is any problem with index update, we can > > proceed > > > > with > > > > >> invalidating the indexes...But we really need to look at making > > region > > > > and > > > > >> index updates in a transactional way, silently invalidating > indexes > > > may > > > > >> not > > > > >> be acceptable... > > > > >> > > > > >> -Anil. > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> On Thu, Sep 14, 2017 at 1:12 PM, Dan Smith <dsm...@pivotal.io> > > wrote: > > > > >> > > > > >> > I'm still going to push that we stick with Naba's original > > proposal. > > > > >> > > > > > >> > The current behavior is clearly broken. If one index update > fails, > > > an > > > > >> > exception gets thrown to the user (nice!) but it leaves the put > > in a > > > > >> > partially completed state - some other indexes may not have been > > > > >> updated, > > > > >> > WAN/AEQs may not have been notified, etc. > > > > >> > > > > > >> > We should never leave the system in this corrupted state. It > would > > > be > > > > >> nice > > > > >> > to be able to cleanly rollback the put, but we don't have that > > > > >> capability > > > > >> > especially considering that cache writers have already been > > invoked. > > > > So > > > > >> the > > > > >> > next best thing is to invalidate the index that failed to > update. > > > > >> > > > > > >> > Logging an error an allowing the put to succeed does match what > we > > > do > > > > >> with > > > > >> > CacheListeners. Exceptions from CacheListeners do not fail the > > put. > > > > >> > > > > > >> > -Dan > > > > >> > > > > > >> > On Mon, Sep 11, 2017 at 3:29 PM, Jason Huynh <jhu...@pivotal.io > > > > > > wrote: > > > > >> > > > > > >> > > Anil, we actually do have a case where the index is out of > sync > > > with > > > > >> the > > > > >> > > region currently. It's just not likely to happen but if there > > is > > > an > > > > >> > > exception from an index, the end result is that certain > indexes > > > get > > > > >> > updated > > > > >> > > and the region has already been updated. > > > > >> > > However the exception is thrown back to the putter, so it > > becomes > > > > very > > > > >> > > obvious something is wrong but I believe Naba has updated the > > > ticket > > > > >> to > > > > >> > > show a test that reproduces the problem... > > > > >> > > > > > > >> > > > > > > >> > > On Mon, Sep 11, 2017 at 2:50 PM Anilkumar Gingade < > > > > >> aging...@pivotal.io> > > > > >> > > wrote: > > > > >> > > > > > > >> > > > The other way to look at it is; what happens to a cache op; > > when > > > > >> there > > > > >> > is > > > > >> > > > an exception after Region.Entry is created? can it happen? > In > > > that > > > > >> > case, > > > > >> > > do > > > > >> > > > we stick the entry into the Cache or not? If an exception is > > > > >> handled, > > > > >> > how > > > > >> > > > is it done, can we look at using the same for Index... > > > > >> > > > > > > > >> > > > Also previously, once the valid index is created (verified > > > during > > > > >> > create > > > > >> > > or > > > > >> > > > first put into the cache); we never had any issue where > index > > is > > > > >> out of > > > > >> > > > sync with cache...If that changes with new futures > (security?) > > > > then > > > > >> we > > > > >> > > may > > > > >> > > > have to change the expectation with indexing... > > > > >> > > > > > > > >> > > > -Anil. > > > > >> > > > > > > > >> > > > > > > > >> > > > > > > > >> > > > On Mon, Sep 11, 2017 at 2:16 PM, Anthony Baker < > > > aba...@pivotal.io > > > > > > > > > >> > > wrote: > > > > >> > > > > > > > >> > > > > I’m confused. Once a cache update has been distributed to > > > other > > > > >> > > members > > > > >> > > > > it can’t be undone. That update could have triggered > myriad > > > > other > > > > >> > > > > application behaviors. > > > > >> > > > > > > > > >> > > > > Anthony > > > > >> > > > > > > > > >> > > > > > On Sep 11, 2017, at 2:04 PM, Michael Stolz < > > > mst...@pivotal.io > > > > > > > > > >> > > wrote: > > > > >> > > > > > > > > > >> > > > > > Great, that's exactly the behavior I would expect. > > > > >> > > > > > > > > > >> > > > > > Thanks. > > > > >> > > > > > > > > > >> > > > > > -- > > > > >> > > > > > Mike Stolz > > > > >> > > > > > Principal Engineer, GemFire Product Manager > > > > >> > > > > > Mobile: +1-631-835-4771 <(631)%20835-4771> > > <(631)%20835-4771> > > > <(631)%20835-4771> > > > > <(631)%20835-4771> <(631)%20835-4771> > > > > >> > > > > > > > > > >> > > > > > On Mon, Sep 11, 2017 at 4:34 PM, Jason Huynh < > > > > jhu...@pivotal.io > > > > >> > > > > > >> > > > wrote: > > > > >> > > > > > > > > > >> > > > > >> Hi Mike, I think the concern was less about the > security > > > > >> portion > > > > >> > but > > > > >> > > > > rather > > > > >> > > > > >> if any exception occurs during index update, right now, > > the > > > > >> region > > > > >> > > > gets > > > > >> > > > > >> updated and the rest of the system > (index/wan/callbacks) > > > may > > > > or > > > > >> > may > > > > >> > > > not > > > > >> > > > > be > > > > >> > > > > >> updated. I think Naba just tried to provide an example > > > where > > > > >> this > > > > >> > > > might > > > > >> > > > > >> occur, but that specific scenario is invalid. > > > > >> > > > > >> > > > > >> > > > > >> I believe Nabarun has opened a ticket for rolling back > > the > > > > put > > > > >> > > > operation > > > > >> > > > > >> when an index exception occurs. GEODE-3589. It can > > > probably > > > > be > > > > >> > > > > modified to > > > > >> > > > > >> state any exception instead of index exceptions. > > > > >> > > > > >> > > > > >> > > > > >> To summarize my understanding: > > > > >> > > > > >> -Someone will need to implement the rollback for > > > GEODE-3589. > > > > >> This > > > > >> > > > means > > > > >> > > > > >> that if any exception occurs during a put, geode it > will > > > > >> propagate > > > > >> > > > back > > > > >> > > > > to > > > > >> > > > > >> the user and it is expected the rollback mechanism will > > > clean > > > > >> up > > > > >> > any > > > > >> > > > > >> partial put. > > > > >> > > > > >> > > > > >> > > > > >> GEODE-3520 should be modified to: > > > > >> > > > > >> -Add the isValid() api to index interface > > > > >> > > > > >> -Mark an index as invalid during async index updates > but > > > not > > > > >> for > > > > >> > > > > >> synchronous index updates. The synchronous index > updates > > > > will > > > > >> > rely > > > > >> > > > on a > > > > >> > > > > >> rollback mechanism > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > > > > >> On Mon, Sep 11, 2017 at 1:23 PM Michael Stolz < > > > > >> mst...@pivotal.io> > > > > >> > > > > wrote: > > > > >> > > > > >> > > > > >> > > > > >>> I think there was an intention of having CREATION of > an > > > > index > > > > >> > > > require a > > > > >> > > > > >>> higher privilege than DATA:WRITE, but it shouldn't > > affect > > > > >> > applying > > > > >> > > > the > > > > >> > > > > >>> index on either of put or get operations. > > > > >> > > > > >>> > > > > >> > > > > >>> If we are requiring something like CLUSTER:MANAGE for > > put > > > on > > > > >> an > > > > >> > > > indexed > > > > >> > > > > >>> region, that is an incorrect requirement. Only > > DATA:WRITE > > > > >> should > > > > >> > be > > > > >> > > > > >>> required to put an entry and have it be indexed if an > > > index > > > > is > > > > >> > > > present. > > > > >> > > > > >>> > > > > >> > > > > >>> -- > > > > >> > > > > >>> Mike Stolz > > > > >> > > > > >>> Principal Engineer, GemFire Product Manager > > > > >> > > > > >>> Mobile: +1-631-835-4771 <(631)%20835-4771> > > <(631)%20835-4771> > > > <(631)%20835-4771> > > > > <(631)%20835-4771> > > > > >> <(631)%20835-4771> <(631)%20835-4771> > > > > >> > > > > >>> > > > > >> > > > > >>> On Fri, Sep 8, 2017 at 6:04 PM, Anilkumar Gingade < > > > > >> > > > aging...@pivotal.io > > > > >> > > > > > > > > > >> > > > > >>> wrote: > > > > >> > > > > >>> > > > > >> > > > > >>>> Indexes are critical for querying; most of the > > databases > > > > >> doesn't > > > > >> > > > allow > > > > >> > > > > >>>> insert/update if there is any failure with index > > > > >> maintenance... > > > > >> > > > > >>>> > > > > >> > > > > >>>> As Geode OQL supports two ways (sync and async) to > > > maintain > > > > >> the > > > > >> > > > > >> indexes, > > > > >> > > > > >>> we > > > > >> > > > > >>>> need be careful about the error handling in both > > cases... > > > > >> > > > > >>>> > > > > >> > > > > >>>> My take is: > > > > >> > > > > >>>> 1. For synchronous index maintenance: > > > > >> > > > > >>>> If there is any failure in updating any index > > > > (security/auth > > > > >> or > > > > >> > > > > logical > > > > >> > > > > >>>> error) on the region; throw an exception and rollback > > the > > > > >> cache > > > > >> > > > > >> update/op > > > > >> > > > > >>>> (index management id done under region.entry lock - > we > > > > >> should be > > > > >> > > > able > > > > >> > > > > >> to > > > > >> > > > > >>>> revert the op). If index or cache is left in bad > state, > > > > then > > > > >> > its a > > > > >> > > > bug > > > > >> > > > > >>> that > > > > >> > > > > >>>> needs to be addressed. > > > > >> > > > > >>>> > > > > >> > > > > >>>> Most of the time, If there is any logical error in > > index, > > > > it > > > > >> > will > > > > >> > > be > > > > >> > > > > >>>> detected as soon as index is created (on existing > data) > > > or > > > > >> when > > > > >> > > > first > > > > >> > > > > >>>> update is done to the cache. > > > > >> > > > > >>>> > > > > >> > > > > >>>> 2. For Asynchronous index maintenance: > > > > >> > > > > >>>> As this is async (assuming) user has good > understanding > > > of > > > > >> the > > > > >> > > risk > > > > >> > > > > >>>> involved with async, any error with index > maintenance, > > > the > > > > >> index > > > > >> > > > > should > > > > >> > > > > >>> be > > > > >> > > > > >>>> invalidated... > > > > >> > > > > >>>> > > > > >> > > > > >>>> About the security/auth, the user permission with > > region > > > > >> > > read/write > > > > >> > > > > >>> needs > > > > >> > > > > >>>> to be applied for index updates, there should not be > > > > >> different > > > > >> > > > > >> permission > > > > >> > > > > >>>> on index. > > > > >> > > > > >>>> > > > > >> > > > > >>>> -Anil. > > > > >> > > > > >>>> > > > > >> > > > > >>>> > > > > >> > > > > >>>> > > > > >> > > > > >>>> On Fri, Sep 8, 2017 at 2:01 PM, Nabarun Nag < > > > > n...@pivotal.io > > > > >> > > > > > >> > > > wrote: > > > > >> > > > > >>>> > > > > >> > > > > >>>>> Hi Mike, > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> Please do find our answers below: > > > > >> > > > > >>>>> *Question:* What if there were multiple indices that > > > were > > > > in > > > > >> > > flight > > > > >> > > > > >> and > > > > >> > > > > >>>>> only the third > > > > >> > > > > >>>>> one errors out, will they all be marked invalid? > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> *Answer:* Only the third will be marked invalid and > > only > > > > the > > > > >> > > third > > > > >> > > > > >> one > > > > >> > > > > >>>> will > > > > >> > > > > >>>>> not be used for query execution. > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> *Question/Statement:* If anything goes wrong with > the > > > put > > > > it > > > > >> > > should > > > > >> > > > > >>>>> probably still throw back to > > > > >> > > > > >>>>> the caller. Silent invalidation of the index is > > probably > > > > not > > > > >> > > > > >> desirable. > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> *Answer: * > > > > >> > > > > >>>>> In our current design this the flow of execution of > a > > > put > > > > >> > > > operation: > > > > >> > > > > >>>>> entry put into region -> update index -> other wan > > > related > > > > >> > > > > >> executions / > > > > >> > > > > >>>>> callbacks etc. > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> If an exception happens while updating the index, > the > > > > cache > > > > >> > gets > > > > >> > > > > >> into a > > > > >> > > > > >>>> bad > > > > >> > > > > >>>>> state, and we may end up getting different results > > > > >> depending on > > > > >> > > the > > > > >> > > > > >>> index > > > > >> > > > > >>>>> we are using. As the failure happens half way in a > put > > > > >> > operation, > > > > >> > > > the > > > > >> > > > > >>>>> regions / cache are now in a bad state. > > > > >> > > > > >>>>> -------------------------- > > > > >> > > > > >>>>> We are thinking that if index is created over a > > method > > > > >> > > invocation > > > > >> > > > in > > > > >> > > > > >>> an > > > > >> > > > > >>>>> empty region and then we do puts, but method > > invocation > > > is > > > > >> not > > > > >> > > > > >> allowed > > > > >> > > > > >>> as > > > > >> > > > > >>>>> per security policies. The puts will now be > successful > > > but > > > > >> the > > > > >> > > > index > > > > >> > > > > >>> will > > > > >> > > > > >>>>> be rendered invalid. Previously the puts will fail > > with > > > > >> > exception > > > > >> > > > and > > > > >> > > > > >>> put > > > > >> > > > > >>>>> the entire cache in a bad state. > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> Regards > > > > >> > > > > >>>>> Nabarun > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> > > > > >> > > > > >>>>> On Fri, Sep 8, 2017 at 10:43 AM Michael Stolz < > > > > >> > mst...@pivotal.io > > > > >> > > > > > > > >> > > > > >>> wrote: > > > > >> > > > > >>>>> > > > > >> > > > > >>>>>> Just to help me understand, the index is corrupted > > in a > > > > way > > > > >> > > beyond > > > > >> > > > > >>> just > > > > >> > > > > >>>>> the > > > > >> > > > > >>>>>> field that errors out? > > > > >> > > > > >>>>>> What if there were multiple indices that were in > > flight > > > > and > > > > >> > only > > > > >> > > > > >> the > > > > >> > > > > >>>>> third > > > > >> > > > > >>>>>> one errors out, will they all be marked invalid? > > > > >> > > > > >>>>>> If anything goes wrong with the put it should > > probably > > > > >> still > > > > >> > > throw > > > > >> > > > > >>> back > > > > >> > > > > >>>>> to > > > > >> > > > > >>>>>> the caller. Silent invalidation of the index is > > > probably > > > > >> not > > > > >> > > > > >>> desirable. > > > > >> > > > > >>>>>> > > > > >> > > > > >>>>>> -- > > > > >> > > > > >>>>>> Mike Stolz > > > > >> > > > > >>>>>> Principal Engineer, GemFire Product Manager > > > > >> > > > > >>>>>> Mobile: +1-631-835-4771 <(631)%20835-4771> > > <(631)%20835-4771> > > > <(631)%20835-4771> > > > > <(631)%20835-4771> > > > > >> <(631)%20835-4771> <(631)%20835-4771> > > > > >> > > > <(631)%20835-4771> > > > > >> > > > > >>>>>> > > > > >> > > > > >>>>>> On Fri, Sep 8, 2017 at 12:34 PM, Dan Smith < > > > > >> dsm...@pivotal.io > > > > >> > > > > > > >> > > > > >>> wrote: > > > > >> > > > > >>>>>> > > > > >> > > > > >>>>>>> +1 > > > > >> > > > > >>>>>>> > > > > >> > > > > >>>>>>> -Dan > > > > >> > > > > >>>>>>> > > > > >> > > > > >>>>>>> On Thu, Sep 7, 2017 at 9:14 PM, Nabarun Nag < > > > > >> n...@apache.org > > > > >> > > > > > > >> > > > > >>> wrote: > > > > >> > > > > >>>>>>> > > > > >> > > > > >>>>>>>> *Proposal:* > > > > >> > > > > >>>>>>>> * Index interface will include an API - isValid() > > > which > > > > >> will > > > > >> > > > > >>> return > > > > >> > > > > >>>>>> true > > > > >> > > > > >>>>>>> if > > > > >> > > > > >>>>>>>> the index is still valid / uncorrupted, else will > > > > return > > > > >> > false > > > > >> > > > > >> if > > > > >> > > > > >>>> it > > > > >> > > > > >>>>>>>> corrupted / invalid. > > > > >> > > > > >>>>>>>> * gfsh command "list index" will have one more > > column > > > > "Is > > > > >> > > > > >> Valid" > > > > >> > > > > >>>>> which > > > > >> > > > > >>>>>>> will > > > > >> > > > > >>>>>>>> state the status as "true" or "false". > > > > >> > > > > >>>>>>>> * Invalid indexes will not be used during query > > > > >> executions. > > > > >> > > > > >>>>>>>> * In case the index is found to be invalid, the > > user > > > > >> will be > > > > >> > > > > >> able > > > > >> > > > > >>>> to > > > > >> > > > > >>>>>>>> remove/destroy the index. > > > > >> > > > > >>>>>>>> * When a put operation corrupts an index, it will > > be > > > > >> logged. > > > > >> > > > > >>>>>>>> > > > > >> > > > > >>>>>>>> *Reasoning:* > > > > >> > > > > >>>>>>>> * Currently if a put operation raises an > exception > > > > while > > > > >> > > > > >> updating > > > > >> > > > > >>>> the > > > > >> > > > > >>>>>>>> index, the put operation fails with an exception > to > > > the > > > > >> > > putter. > > > > >> > > > > >>>>>>>> * For example, if an index is created on an > object > > > > >> method, > > > > >> > and > > > > >> > > > > >>> that > > > > >> > > > > >>>>>>> method > > > > >> > > > > >>>>>>>> causes an exception while updating the index as a > > > part > > > > >> of a > > > > >> > > put > > > > >> > > > > >>>>>>> operation, > > > > >> > > > > >>>>>>>> then the put operation fails for that particular > > > entry > > > > >> and > > > > >> > the > > > > >> > > > > >>>> index > > > > >> > > > > >>>>> is > > > > >> > > > > >>>>>>>> left in a bad state. > > > > >> > > > > >>>>>>>> * This may occur also due to lack of permission > to > > > > update > > > > >> > > index > > > > >> > > > > >>> but > > > > >> > > > > >>>>>> have > > > > >> > > > > >>>>>>>> permission to do puts. > > > > >> > > > > >>>>>>>> * We are proposing that in the above mentioned > > > > scenarios, > > > > >> > the > > > > >> > > > > >> put > > > > >> > > > > >>>>>>> succeeds > > > > >> > > > > >>>>>>>> in putting the entry in the region but the index > > > which > > > > it > > > > >> > was > > > > >> > > > > >>>> trying > > > > >> > > > > >>>>> to > > > > >> > > > > >>>>>>>> update will be marked invalid and will not be > used > > > for > > > > >> query > > > > >> > > > > >>>>>> executions. > > > > >> > > > > >>>>>>>> * This can be justified because the corrupted > index > > > > will > > > > >> not > > > > >> > > > > >>>>> correctly > > > > >> > > > > >>>>>>>> represent the region entries. > > > > >> > > > > >>>>>>>> > > > > >> > > > > >>>>>>>> *Status Quo:* > > > > >> > > > > >>>>>>>> * Index creation will still fail if we are trying > > to > > > > >> create > > > > >> > an > > > > >> > > > > >>>> index > > > > >> > > > > >>>>>>> over a > > > > >> > > > > >>>>>>>> region containing an entry/entries which will > > cause > > > an > > > > >> > > > > >> exception > > > > >> > > > > >>>>> while > > > > >> > > > > >>>>>>>> loading the entry into the index. > > > > >> > > > > >>>>>>>> > > > > >> > > > > >>>>>>>> Regards > > > > >> > > > > >>>>>>>> Nabarun Nag > > > > >> > > > > >>>>>>>> > > > > >> > > > > >>>>>>> > > > > >> > > > > >>>>>> > > > > >> > > > > >>>>> > > > > >> > > > > >>>> > > > > >> > > > > >>> > > > > >> > > > > >> > > > > >> > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > > > > > >
