Missing ways to get access to Ignite CacheEntry
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Re: Missing ways to get access to Ignite CacheEntry
 
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On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda <[hidden email]> wrote: > >> Why it shouldn't work? >> If client receives an entry that has a reference to the entry with >> version, transferred from a server as well as a part of the response, then >> unwrap(...) should work. >> Isn't this feasible to implement? >> > The reason is consistency. If getEntry(…) can be unwrapped on the client > side, then all the query results should be un-wrappable as well, which > means that we have to always carry the cache version, even if user does not > need it. someone needs an entry with a version on a client. In all other cases (queries, etc.) the version won't be a part of a response. Right, this is inconsistent but if to document everything well then the user will only benefit from the new getEntry(...) method. CacheEntry with version is already can be unwrapped from specific places that are listed in its documentation. We will just broaden the list. -- Denis > > My preference is that unwrap(..) on the client side should result in > UnsupportedOperationException(…). > > >> -- >> Denis >> >> >> On 12/21/2015 10:59 AM, Dmitriy Setrakyan wrote: >> >>> Again, my issue is with unwrap method. Are we all in agreement that >>> unwrap(…) will not work on the client side? >>> >>> D. >>> >>> On Sun, Dec 20, 2015 at 11:30 PM, Denis Magda <[hidden email]> >>> wrote: >>> >>> Actually I think that Andrey's proposal on addition of >>>> IgniteCache.getEntry(k) sounds natural. >>>> >>>> Is there any platform limitation that will prevent us from loading an >>>> entry with its version from a remote node when such a particular method >>>> is >>>> used? >>>> I think that it's feasible to support it and in addition I would add on >>>> more method to the API - IgniteCache.getAllEntries(keysSet). >>>> >>>> -- >>>> Denis >>>> >>>> >>>> On 12/19/2015 2:05 AM, Dmitriy Setrakyan wrote: >>>> >>>> On Fri, Dec 18, 2015 at 1:23 PM, Andrey Kornev <[hidden email] >>>>> wrote: >>>>> >>>>> How would I know how to interpret the returned null? >>>>> >>>>>> Can we just have a simple getEntry(K) method that has semantics of the >>>>>> regular get(K)? Why invent something? >>>>>> >>>>>> If we do this, how would you unwrap such entry on the client side? >>>>>> >>>>> Cheers >>>>> >>>>>> Andrey >>>>>> >>>>>> From: [hidden email] >>>>>> >>>>>>> Date: Fri, 18 Dec 2015 12:55:47 -0800 >>>>>>> Subject: Re: Missing ways to get access to Ignite CacheEntry >>>>>>> To: [hidden email] >>>>>>> >>>>>>> On Fri, Dec 18, 2015 at 12:40 PM, Andrey Kornev < >>>>>>> >>>>>>> [hidden email]> >>>>>> wrote: >>>>>>> Dmitriy, >>>>>>> >>>>>>>> I understand that we're talking about Ignite CacheEntry and not >>>>>>>> >>>>>>>> JCache's >>>>>>> CacheEntry that has no version property to speak of. >>>>>>> >>>>>>>> But I don't understand why the method is named localEntry()? What >>>>>>>> does >>>>>>>> "local" mean in this context? Does it mean that I can only use it on >>>>>>>> >>>>>>>> the >>>>>>> primary node for a given key? What would happen if I call this method >>>>>>> on a >>>>>>> non-primary node? And what would I do if I needed the entry (along >>>>>>> with the >>>>>>> valid version it contains) on a non-primary node? >>>>>>> >>>>>>>> If the node is either primary or backup, then you will get the entry >>>>>>>> >>>>>>> back. >>>>>> Otherwise, you will get null. >>>>>>> >>>>>>> From: [hidden email] >>>>>>> >>>>>>>> Date: Fri, 18 Dec 2015 12:19:01 -0800 >>>>>>>>> Subject: Re: Missing ways to get access to Ignite CacheEntry >>>>>>>>> To: [hidden email] >>>>>>>>> >>>>>>>>> On Fri, Dec 18, 2015 at 9:47 AM, Andrey Kornev < >>>>>>>>> >>>>>>>>> [hidden email] >>>>>>> wrote: >>>>>>> >>>>>>>> Dmitriy, >>>>>>>>>> Based on what criteria does one determine which information is >>>>>>>>>> >>>>>>>>>> redundant >>>>>>>>> and which is not? >>>>>>>>> >>>>>>>>>> To me, if an API declares a method getSomeRedundantInfo(), then the >>>>>>>>>> implementer has no choice, but to comply with the contract and >>>>>>>>>> >>>>>>>>>> provide >>>>>>>> such >>>>>>>> info. One can't just return a null or ignore it some other way, >>>>>>>>> simply >>>>>>>>> >>>>>>>> because it appears to have some performance impact. >>>>>>>> Andrey, the CacheEntry is not the JCache entry, but rather the >>>>>>>>> internal >>>>>>> Ignite entry that you can get when unwrapping the JCache entry. The >>>>>>> >>>>>>>> unwrapping, obviously, can only happen on the server side. >>>>>>>>> Therefore, I >>>>>>> am >>>>>>> >>>>>>>> suggesting that we also add a localEntry(K) method which will >>>>>>>>> provide the >>>>>>> entry API on the server side directly (not from iterator or EP). >>>>>>> >>>>>>>> Now I understand that the version() method currently does not work >>>>>>>>> properly >>>>>>>> on the server side, but this is something we can easily fix. >>>>>>>>> Thoughts? >>>>>>>>> >>>>>>>>> >>>>>>>>> Besides, the overhead of the version number may turn out to be >>>>>>>>> negligible >>>>>>>>> when benchmarked. Most likely there will be near zero overhead >>>>>>>>> (due to >>>>>>>>> >>>>>>>> the >>>>>>>> way the network stack packs the bytes into the ethernet frames). >>>>>>>>> The >>>>>>>>> >>>>>>>> workaround for the broken API however may be much more expensive in >>>>>>>> terms >>>>>>>>> of performance and user experience. >>>>>>>>> >>>>>>>>>> Please let's keep the API consistent and predictable. >>>>>>>>>> >>>>>>>>>> Regards >>>>>>>>>> Andrey >>>>>>>>>> >>>>>>>>>> From: [hidden email] >>>>>>>>>> >>>>>>>>>>> Date: Fri, 18 Dec 2015 08:41:00 -0800 >>>>>>>>>>> Subject: Re: Missing ways to get access to Ignite CacheEntry >>>>>>>>>>> To: [hidden email] >>>>>>>>>>> >>>>>>>>>>> Andrey, >>>>>>>>>>> >>>>>>>>>>> The main issue with returning version is sending redundant >>>>>>>>>>> >>>>>>>>>>> information >>>>>>>>> over >>>>>>>>> >>>>>>>>>> the wire. What if we added a method IgniteCache.localEntry(K) >>>>>>>>>>> which >>>>>>>>> would >>>>>>>> return a local entry instance with a version. You would only be >>>>>>>>>> able >>>>>>>>>> >>>>>>>>> to >>>>>>>> invoke this method on the server node (not client). >>>>>>>>>> Would this work for you? >>>>>>>>>>> D. >>>>>>>>>>> >>>>>>>>>>> On Fri, Dec 18, 2015 at 8:23 AM, Andrey Kornev < >>>>>>>>>>> >>>>>>>>>>> [hidden email] >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Denis, >>>>>>>>>>>> I'm not suggesting to have every cache read operation return a >>>>>>>>>>>> >>>>>>>>>>>> CacheEntry. >>>>>>>>>>> The "classical" GridGain used to have a getEntry(key) method >>>>>>>>>>> that >>>>>>>>>>> >>>>>>>>>> was >>>>>>>> very >>>>>>>>>> useful. The current version of Ignite provides virtually no >>>>>>>>>>> way of >>>>>>>>>>> >>>>>>>>>> obtaining a cache entry except thru an iterator, or using an >>>>>>>> EntryProcessor >>>>>>>>>>> invocation which seems more like a hack. >>>>>>>>>>> >>>>>>>>>>>> As for the question of what's stored in Ignite cache and the >>>>>>>>>>>> >>>>>>>>>>>> pre-compute, >>>>>>>>>>> it is really an off-topic. It just came about as we were >>>>>>>>>>> looking >>>>>>>>>>> >>>>>>>>>> for a >>>>>>>> way >>>>>>>>>> to work around the issue with Ignite query not returning cache >>>>>>>>>>> entries' >>>>>>>>>>> >>>>>>>>>> version numbers in the result iterator. (There is now a ticket >>>>>>>>>> that >>>>>>>>>> addresses this issue: >>>>>>>> https://issues.apache.org/jira/browse/IGNITE-2202 >>>>>>>>>>> )This is when we realized that there is no longer any way in >>>>>>>>>>> Ignite to >>>>>>>>>>> >>>>>>>>>> retrieve the CacheEntry by its key. >>>>>>>>>> But for the sake of completeness I quickly go over the entire >>>>>>>>>>>> use >>>>>>>>>> case, >>>>>>>> because it seems I wasn't clear enough in the previous post. >>>>>>>>>> Ignite cache holds the data entries that are used as the input >>>>>>>>>>>> into >>>>>>>>>> some >>>>>>>> expensive computation. The data in the cache gets updated from >>>>>>>>>>> time to >>>>>>>>>>> >>>>>>>>>> time, the computation only needs to be re-run >>>>>>>>>> - on-demand -- when a user asks for the computed value and >>>>>>>>>>>> - the pre-computed value is obsolete -- the source cache data >>>>>>>>>>>> >>>>>>>>>>>> has >>>>>>>>>> been >>>>>>>> updated since the last time the value was computed. >>>>>>>>>> Otherwise, we return the pre-computed value. Note that we don't >>>>>>>>>>>> want to >>>>>>>>>> rerun the computation for each cache update! Only when the >>>>>>>>>> users >>>>>>>>>> asks >>>>>>>> for >>>>>>>>>> it. >>>>>>>>>>>> I hope it make it more clear now. >>>>>>>>>>>> >>>>>>>>>>>> Thanks >>>>>>>>>>>> Andrey >>>>>>>>>>>> >>>>>>>>>>>> Subject: Re: Missing ways to get access to Ignite CacheEntry >>>>>>>>>>>> >>>>>>>>>>>>> To: [hidden email] >>>>>>>>>>>>> From: [hidden email] >>>>>>>>>>>>> Date: Fri, 18 Dec 2015 13:44:16 +0300 >>>>>>>>>>>>> >>>>>>>>>>>>> Hi Andrey, >>>>>>>>>>>>> >>>>>>>>>>>>> I got you, thanks for the clarification. >>>>>>>>>>>>> >>>>>>>>>>>>> So since you're storing a computed value in some local data >>>>>>>>>>>>> >>>>>>>>>>>>> structure >>>>>>>>>>> what is stored in the Ignite cache as a value in such a case? >>>>>>>>>> There >>>>>>>>>>> should be something. >>>>>>>>>> Why don't you (or can't you) store a version identifier in >>>>>>>>>>>>> that >>>>>>>>>>> value >>>>>>>> that is located in the Ignite cache? This should work >>>>>>>>>> perfectly >>>>>>>>>>> well >>>>>>>> for >>>>>>>>>> you use-case. >>>>>>>>>>>> Personally I'm against adding CacheEntry to a response of >>>>>>>>>>>>> every >>>>>>>>>>> get >>>>>>>> like >>>>>>>>>> operation that happens over a cache (get, getAll, SQL & Scan >>>>>>>>>>>> queries). >>>>>>>>>>>> >>>>>>>>>>> This will add extra size to every response and only in rare >>>>>>>>>>> >>>>>>>>>>>> cases >>>>>>>>>>>> >>>>>>>>>>> someone will benefit from it. >>>>>>>> However, what if we add a special configuration parameter to >>>>>>>>>>>>> CacheConfiguration that will manage whether CacheEntry has >>>>>>>>>>>>> >>>>>>>>>>>>> to be >>>>>>>>>>> passed >>>>>>>> as a part of a response or not? Igniters, what do you think >>>>>>>>>>>> on >>>>>>>>>>>> >>>>>>>>>>> this? >>>>>>>> Regards, >>>>>>>>>>>>> Denis >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> On 12/17/2015 9:09 AM, Andrey Kornev wrote: >>>>>>>>>>>>> >>>>>>>>>>>>> Denis,In this case I used the term "caching" in general >>>>>>>>>>>>>> sense, >>>>>>>>>>>> meaning >>>>>>>> saving the computed value for later. I didn't mean the Ignite >>>>>>>>>>> cache.Sorry >>>>>>>>>>> about the confusion.Andrey >>>>>>>>>>> >>>>>>>>>>>> _____________________________ >>>>>>>>>>>>>> From: Denis Magda <[hidden email]> >>>>>>>>>>>>>> Sent: Wednesday, December 16, 2015 9:48 PM >>>>>>>>>>>>>> Subject: Re: Missing ways to get access to Ignite >>>>>>>>>>>>>> >>>>>>>>>>>>>> CacheEntry >>>>>>>>>>>> To: <[hidden email]> >>>>>>>>>>>>>> Hi Romain, >>>>>>>>>>>>>> >>>>>>>>>>>>>> I'm a bit confused cause initially you saying that >>>>>>>>>>>>>> >>>>>>>>>>>>>> /The value is computed on first access and it is then >>>>>>>>>>>>>> >>>>>>>>>>>>>> cached >>>>>>>>>>>> /and then you add that >>>>>>>> /One constraint is that the computed value is not >>>>>>>>>>>>>> serializable. >>>>>>>>>>>> // >>>>>>>>>> / >>>>>>>>>>>>>> Ignite won't be able to store a value of cache if >>>>>>>>>>>>>> >>>>>>>>>>>>>> serialization >>>>>>>>>>>> is >>>>>>>>>> not >>>>>>>>>>>> supported for it by some reason. >>>>>>>>>>>>>> Please clarify here. Probably I'm missing something from >>>>>>>>>>>>>> >>>>>>>>>>>>>> your >>>>>>>>>>>> description. >>>>>>>> -- >>>>>>>>>>>>>> Denis >>>>>>>>>>>>>> >>>>>>>>>>>>>> On 12/16/2015 6:21 PM, Andrey Kornev wrote: >>>>>>>>>>>>>> > Romain >>>>>>>>>>>>>> > >>>>>>>>>>>>>> > I suggest you be very careful using the invoke() >>>>>>>>>>>>>> >>>>>>>>>>>>>> functionality. As >>>>>>>>>>>> explained in this posting (and the follow-ups) >>>>>>>>>>>> > >>>>>> http://mail-archives.apache.org/mod_mbox/ignite-dev/201511.mbox/%3CSNT147-W14D2736E1374450B685721CF000%40phx.gbl%3E >>>>>> >>>>>> > the correct usage of the invoke() may be difficult, to >>>>>>>> put >>>>>>>>>>>> it >>>>>>>> politely. >>>>>>>>>> > >>>>>>>>>>>>>> > @Denis Very briefly, the use case is "conditional >>>>>>>>>>>>>> >>>>>>>>>>>>>> re-compute". >>>>>>>>>>>> There is a pretty expensive computation that needs to be >>>>>>>>>> applied to >>>>>>>>>> each >>>>>>>> entry on demand. The value is computed on first access and it >>>>>>>>>>> is >>>>>>>>>>> >>>>>>>>>> then >>>>>>>> cached along with the current version of the cache entry. The >>>>>>>>>> value >>>>>>>>>> must >>>>>>>>>> be recomputed on next access only if the entry has been >>>>>>>>>>> modified. >>>>>>>>>>> >>>>>>>>>> > >>>>>>>> > If anyone has a better idea how to achieve something >>>>>>>>>>>>>> like >>>>>>>>>>>> that, >>>>>>>> please do share! One constraint is that the computed value is >>>>>>>>>> not >>>>>>>>>> serializable. >>>>>>>> > >>>>>>>>>>>>>> > Cheers >>>>>>>>>>>>>> > Andrey >>>>>>>>>>>>>> > >>>>>>>>>>>>>> >> Subject: Re: Missing ways to get access to Ignite >>>>>>>>>>>>>> >>>>>>>>>>>>>> CacheEntry >>>>>>>>>>>> >> To: [hidden email] >>>>>>>>>> >> From: [hidden email] >>>>>>>>>>>>>> >> Date: Wed, 16 Dec 2015 16:11:48 +0300 >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> >> Romain, >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> >> If it's implemented this way for now it doesn't mean >>>>>>>>>>>>>> >>>>>>>>>>>>>> that >>>>>>>>>>>> we >>>>>>>> can't >>>>>>>>>> >> enhance the API for other use cases ;) >>>>>>>>>>>> >> As I said presently it's supported for limited number >>>>>>>>>>>>>> of >>>>>>>>>>>> methods >>>>>>>> mostly >>>>>>>>>>>> >> by performance reasons. >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> >> Please go ahead and try invoke/invokeAll and if it >>>>>>>>>>>>>> >>>>>>>>>>>>>> doesn't >>>>>>>>>>>> work >>>>>>>> fine for >>>>>>>>>>>> >> you we can keep discussing what to do next. >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> >> Regards, >>>>>>>>>>>>>> >> Denis >>>>>>>>>>>>>> >> >>>>>>>>>>>>>> >> On 12/16/2015 1:53 PM, Romain Gilles wrote: >>>>>>>>>>>>>> >>> Hi Denis, >>>>>>>>>>>>>> >>> Thanks for you replay. And sorry to not double check >>>>>>>>>>>>>> >>>>>>>>>>>>>> it >>>>>>>>>>>> before. >>>>>>>> I see that >>>>>>>>>>>> >>> if I want to work with CacheEntry, I need to use the >>>>>>>>>>>>> invoke >>>>>>>>>>>>> >>>>>>>>>>>> method in order >>>>>>>>>> >>> to return the CacheEntry. This is the way I should do >>>>>>>>>>>>> it. It >>>>>>>>>>>>> >>>>>>>>>>>> sounds like >>>>>>>>>> >>> complicated for "just" getting an entry. But if you >>>>>>>>>>>>> say >>>>>>>>>>>>> >>>>>>>>>>>> this >>>>>>>> is >>>>>>>>>> the way I >>>>>>>>>>>> >>> will do it like that. I was just think that it could >>>>>>>>>>>>> be a >>>>>>>>>>>>> >>>>>>>>>>>> common >>>>>>>> use case >>>>>>>>>>>> >>> and therefore provide it as a shortcut. >>>>>>>>>>>>>> >>> >>>>>>>>>>>>>> >>> Thanks, >>>>>>>>>>>>>> >>> >>>>>>>>>>>>>> >>> Romain. >>>>>>>>>>>>>> >>> >>>>>>>>>>>>>> >>> Le mer. 16 déc. 2015 à 11:34, Denis Magda < >>>>>>>>>>>>>> >>>>>>>>>>>>>> [hidden email]> >>>>>>>>>>>> a écrit : >>>>>>>>>>>> >>> >>>>>>>>>>>>>> >>>> Hi Romain, >>>>>>>>>>>>>> >>>> >>>>>>>>>>>>>> >>>> As the current documentation of >>>>>>>>>>>>>> >>>>>>>>>>>>>> org.apache.ignite.cache.CacheEntry >>>>>>>>>>>>> >>>> states it's possible to get a reference to >>>>>>>>>>>>> CacheEntry >>>>>>>>>>>>> >>>>>>>>>>>> and >>>>>>>> its >>>>>>>>>> version >>>>>>>>>>>> >>>> only for methods that are executed over local data >>>>>>>>>>>>> set >>>>>>>>>>>>> >>>>>>>>>>>> stored >>>>>>>> on a node. >>>>>>>>>>>> >>>> Among such methods are invoke & invokeAll and >>>>>>>>>>>>> randomEntry. >>>>>>>>>>>>> >>>>>>>>>>>> >>>> >>>>>>>>>> >>>> You probably can get a CacheEntry and its non null >>>>>>>>>>>>>> version >>>>>>>>>>>> when >>>>>>>>>> a cache >>>>>>>>>>>> >>>> iterator is in use but the version will be 'null', >>>>>>>>>>>>> as >>>>>>>>>>>>> >>>>>>>>>>>> far >>>>>>>> as I >>>>>>>>>> remember, >>>>>>>>>>>> >>>> for those entries that are loaded from remote nodes. >>>>>>>>>>>>>> >>>> Presently Ignite doesn't transfer the version from >>>>>>>>>>>>>> >>>>>>>>>>>>>> remote >>>>>>>>>>>> nodes >>>>>>>>>> as a >>>>>>>>>>>> >>>> part of response by perform reasons. >>>>>>>>>>>>>> >>>> >>>>>>>>>>>>>> >>>> Please elaborate more on your particular use case >>>>>>>>>>>>>> >>>>>>>>>>>>>> and >>>>>>>>>>>> what >>>>>>>> API >>>>>>>>>> you would >>>>>>>>>>>> >>>> like to add in order to support it. >>>>>>>>>>>>>> >>>> >>>>>>>>>>>>>> >>>> -- >>>>>>>>>>>>>> >>>> Denis >>>>>>>>>>>>>> >>>> >>>>>>>>>>>>>> >>>> On 12/16/2015 12:58 PM, Romain Gilles wrote: >>>>>>>>>>>>>> >>>>> Hi Igniters, >>>>>>>>>>>>>> >>>>> I'm looking for a way to get access to the Ignite >>>>>>>>>>>>>> >>>>>>>>>>>>>> CacheEntry. >>>>>>>>>>>> For now >>>>>>>>>>>> >>>> this >>>>>>>>>>>>>> >>>>> is the ways I found: >>>>>>>>>>>>>> >>>>> >>>>>>>>>>>>>> >>>>> - Through the queris >>>>>>>>>>>>>> >>>>> - Through jsr 107 Cache Iterable >>>>>>>>>>>>>> >>>>> - Through jsr 107 Cache itterator >>>>>>>>>>>>>> >>>>> - Through IgniteCache::randomEntry() >>>>>>>>>>>>>> >>>>> >>>>>>>>>>>>>> >>>>> If I remember correctly it was possible to get the >>>>>>>>>>>>>> >>>>>>>>>>>>>> CacheEntry >>>>>>>>>>>> from a >>>>>>>>>>>> >>>> given >>>>>>>>>>>>>> >>>>> key in old version of gridgain community >>>>>>>>>>>>>> >>>>> version: GridCacheProjection::entry(K key) >>>>>>>>>>>>>> >>>>>>>>>>>>>> GridCacheEntry<K,V> >>>>>>>>>>>> >>>>> I think it could be a good to introduce this >>>>>>>>>>>> feature at >>>>>>>>>>>> IgniteCache >>>>>>>> >>>> level. >>>>>>>>>>>>>> >>>>> Or maybe there is an other way to do it. >>>>>>>>>>>>>> >>>>> >>>>>>>>>>>>>> >>>>> Thanks, >>>>>>>>>>>>>> >>>>> >>>>>>>>>>>>>> >>>>> Romain. >>>>>>>>>>>>>> >>>>> >>>>>>>>>>>>>> > >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> |
Re: Missing ways to get access to Ignite CacheEntry
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On Mon, Dec 21, 2015 at 12:36 AM, Denis Magda <[hidden email]> wrote:
> > > On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > >> On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda <[hidden email]> >> wrote: >> >> Why it shouldn't work? >>> If client receives an entry that has a reference to the entry with >>> version, transferred from a server as well as a part of the response, >>> then >>> unwrap(...) should work. >>> Isn't this feasible to implement? >>> >>> The reason is consistency. If getEntry(…) can be unwrapped on the client >> side, then all the query results should be un-wrappable as well, which >> means that we have to always carry the cache version, even if user does >> not >> need it. >> > The proposal is to add getEntry(...) method exactly for the cases when > someone needs an entry with a version on a client. > In all other cases (queries, etc.) the version won't be a part of a > response. > > Right, this is inconsistent but if to document everything well then the > user will only benefit from the new getEntry(...) method. > CacheEntry with version is already can be unwrapped from specific places > that are listed in its documentation. We will just broaden the list. > Romain, Andrey, can you please comment? |
RE: Missing ways to get access to Ignite CacheEntry
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Couple of points.
First, if it were up to me, I'd keep the API simple & consistent by always providing the version as defined by Ignite's CacheEntry interface, regardless whether it's the query who produces the entry or a specialized method like getEntry(). Which node is going to consume the data -- a "client" or "server" -- should not matter either. In this case, however a concern about perceived performance losses due to the version overhead has apparently trumped any API integrity and consistency concerns. Second, given the first point, here's what I think we could do to keep everybody (the performance kids and the consistency/integrity old-farts) happy. ))) 1) getEntry(K) unconditionally always returns a valid version regardless whether it's called from a client or server. In fact, the only reason to ever use this method is to get the entry version. I'd even suggest going one step further and have the getEntry() method return Ignite's CacheEntry interface rather than JCache's Cache.Entry (only to be immediately unwrapped to Ignite's CacheEntry). 2) for queries, provide an option on the Ignite's Query class (say, setIncludeEntryVersion(boolean)) that would control whether the query should send the version back. By default, it'd be "false" as to have no impact on performance. More advanced users ;) would still be able to enjoy API consistency by setting that option to "true". Deal? Andrey > From: [hidden email] > Date: Mon, 21 Dec 2015 08:30:02 -0800 > Subject: Re: Missing ways to get access to Ignite CacheEntry > To: [hidden email] > > On Mon, Dec 21, 2015 at 12:36 AM, Denis Magda <[hidden email]> wrote: > > > > > > > On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > > > >> On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda <[hidden email]> > >> wrote: > >> > >> Why it shouldn't work? > >>> If client receives an entry that has a reference to the entry with > >>> version, transferred from a server as well as a part of the response, > >>> then > >>> unwrap(...) should work. > >>> Isn't this feasible to implement? > >>> > >>> The reason is consistency. If getEntry(…) can be unwrapped on the client > >> side, then all the query results should be un-wrappable as well, which > >> means that we have to always carry the cache version, even if user does > >> not > >> need it. > >> > > The proposal is to add getEntry(...) method exactly for the cases when > > someone needs an entry with a version on a client. > > In all other cases (queries, etc.) the version won't be a part of a > > response. > > > > Right, this is inconsistent but if to document everything well then the > > user will only benefit from the new getEntry(...) method. > > CacheEntry with version is already can be unwrapped from specific places > > that are listed in its documentation. We will just broaden the list. > > > > Romain, Andrey, can you please comment? |
Re: Missing ways to get access to Ignite CacheEntry
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Andrey,
You got me thinking on whether I belong to the playful performance kids category, or to the old-fart consistency crowd :) I agree on the getEntry(…) suggestion, and I think it would be fairly easy to implement, even for the new community members. As far as including version into query results, it seems like a larger undertaking, and seems like it may pollute the existing implementation with additional hacky code branches. I suggest adding a ticket for the getEntry(…) method only for now. What do you think? D. On Mon, Dec 21, 2015 at 10:19 AM, Andrey Kornev <[hidden email]> wrote: > Couple of points. > > First, if it were up to me, I'd keep the API simple & consistent by > always providing the version as defined by Ignite's CacheEntry interface, > regardless whether it's the query who produces the entry or a specialized > method like getEntry(). Which node is going to consume the data -- a > "client" or "server" -- should not matter either. In this case, however a > concern about perceived performance losses due to the version overhead has > apparently trumped any API integrity and consistency concerns. > > Second, given the first point, here's what I think we could do to keep > everybody (the performance kids and the consistency/integrity old-farts) > happy. ))) > > 1) getEntry(K) unconditionally always returns a valid version regardless > whether it's called from a client or server. In fact, the only reason to > ever use this method is to get the entry version. I'd even suggest going > one step further and have the getEntry() method return Ignite's CacheEntry > interface rather than JCache's Cache.Entry (only to be immediately > unwrapped to Ignite's CacheEntry). > > 2) for queries, provide an option on the Ignite's Query class (say, > setIncludeEntryVersion(boolean)) that would control whether the query > should send the version back. By default, it'd be "false" as to have no > impact on performance. More advanced users ;) would still be able to enjoy > API consistency by setting that option to "true". > > Deal? > Andrey > > > From: [hidden email] > > Date: Mon, 21 Dec 2015 08:30:02 -0800 > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > To: [hidden email] > > > > On Mon, Dec 21, 2015 at 12:36 AM, Denis Magda <[hidden email]> > wrote: > > > > > > > > > > > On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > > > > > >> On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda <[hidden email]> > > >> wrote: > > >> > > >> Why it shouldn't work? > > >>> If client receives an entry that has a reference to the entry with > > >>> version, transferred from a server as well as a part of the response, > > >>> then > > >>> unwrap(...) should work. > > >>> Isn't this feasible to implement? > > >>> > > >>> The reason is consistency. If getEntry(…) can be unwrapped on the > client > > >> side, then all the query results should be un-wrappable as well, which > > >> means that we have to always carry the cache version, even if user > does > > >> not > > >> need it. > > >> > > > The proposal is to add getEntry(...) method exactly for the cases when > > > someone needs an entry with a version on a client. > > > In all other cases (queries, etc.) the version won't be a part of a > > > response. > > > > > > Right, this is inconsistent but if to document everything well then the > > > user will only benefit from the new getEntry(...) method. > > > CacheEntry with version is already can be unwrapped from specific > places > > > that are listed in its documentation. We will just broaden the list. > > > > > > > Romain, Andrey, can you please comment? > > |
RE: Missing ways to get access to Ignite CacheEntry
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Personally, I'm firmly in the old-farts camp -- I like things consistent. :))) My motto is: get things right first, and then make them fast.
As for the queries, I don't understand why do you think that supporting the version would mean adding lots of branching code? One would only have 2 implementations of Ignite's CacheEntry - one with the version field and another -- without. The latter would just throw an UnsupportedOperationException or something like that when user calls CacheEntry.version(). Then, I imagine there would be only one place in the code where the decision as to which implementation to use would have to be made. Based on the value of Query's includeEntryVersion flag the code would instantiate either one implementation class or another. That's it. Am I oversimplifying? For my use case, I'm actually very interested in adding the entry version support to the queries. The getEntry() came out of the realization that Ignite doesn't currently provide any way to atomically obtain a cache value along with its version. Truth be told, the EntryProcessor could also be used as a last resort workaround, but given its current rather unfortunate implementation, we decided against it. Regards Andrey > From: [hidden email] > Date: Mon, 21 Dec 2015 12:15:50 -0800 > Subject: Re: Missing ways to get access to Ignite CacheEntry > To: [hidden email] > > Andrey, > > You got me thinking on whether I belong to the playful performance kids > category, or to the old-fart consistency crowd :) > > I agree on the getEntry(…) suggestion, and I think it would be fairly easy > to implement, even for the new community members. As far as including > version into query results, it seems like a larger undertaking, and seems > like it may pollute the existing implementation with additional hacky code > branches. > > I suggest adding a ticket for the getEntry(…) method only for now. What do > you think? > > D. > > On Mon, Dec 21, 2015 at 10:19 AM, Andrey Kornev <[hidden email]> > wrote: > > > Couple of points. > > > > First, if it were up to me, I'd keep the API simple & consistent by > > always providing the version as defined by Ignite's CacheEntry interface, > > regardless whether it's the query who produces the entry or a specialized > > method like getEntry(). Which node is going to consume the data -- a > > "client" or "server" -- should not matter either. In this case, however a > > concern about perceived performance losses due to the version overhead has > > apparently trumped any API integrity and consistency concerns. > > > > Second, given the first point, here's what I think we could do to keep > > everybody (the performance kids and the consistency/integrity old-farts) > > happy. ))) > > > > 1) getEntry(K) unconditionally always returns a valid version regardless > > whether it's called from a client or server. In fact, the only reason to > > ever use this method is to get the entry version. I'd even suggest going > > one step further and have the getEntry() method return Ignite's CacheEntry > > interface rather than JCache's Cache.Entry (only to be immediately > > unwrapped to Ignite's CacheEntry). > > > > 2) for queries, provide an option on the Ignite's Query class (say, > > setIncludeEntryVersion(boolean)) that would control whether the query > > should send the version back. By default, it'd be "false" as to have no > > impact on performance. More advanced users ;) would still be able to enjoy > > API consistency by setting that option to "true". > > > > Deal? > > Andrey > > > > > From: [hidden email] > > > Date: Mon, 21 Dec 2015 08:30:02 -0800 > > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > > To: [hidden email] > > > > > > On Mon, Dec 21, 2015 at 12:36 AM, Denis Magda <[hidden email]> > > wrote: > > > > > > > > > > > > > > > On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > > > > > > > >> On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda <[hidden email]> > > > >> wrote: > > > >> > > > >> Why it shouldn't work? > > > >>> If client receives an entry that has a reference to the entry with > > > >>> version, transferred from a server as well as a part of the response, > > > >>> then > > > >>> unwrap(...) should work. > > > >>> Isn't this feasible to implement? > > > >>> > > > >>> The reason is consistency. If getEntry(…) can be unwrapped on the > > client > > > >> side, then all the query results should be un-wrappable as well, which > > > >> means that we have to always carry the cache version, even if user > > does > > > >> not > > > >> need it. > > > >> > > > > The proposal is to add getEntry(...) method exactly for the cases when > > > > someone needs an entry with a version on a client. > > > > In all other cases (queries, etc.) the version won't be a part of a > > > > response. > > > > > > > > Right, this is inconsistent but if to document everything well then the > > > > user will only benefit from the new getEntry(...) method. > > > > CacheEntry with version is already can be unwrapped from specific > > places > > > > that are listed in its documentation. We will just broaden the list. > > > > > > > > > > Romain, Andrey, can you please comment? > > > > |
Re: Missing ways to get access to Ignite CacheEntry
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Andrey,
I think getEntry(…) can be done quickly. Adding another serialization mechanism for cache entries together with a configuration flag may take additional time. I would suggest, again, starting with getEntry method and then moving down to queries. D. On Mon, Dec 21, 2015 at 1:04 PM, Andrey Kornev <[hidden email]> wrote: > Personally, I'm firmly in the old-farts camp -- I like things consistent. > :))) My motto is: get things right first, and then make them fast. > > As for the queries, I don't understand why do you think that supporting > the version would mean adding lots of branching code? One would only have 2 > implementations of Ignite's CacheEntry - one with the version field and > another -- without. The latter would just throw an > UnsupportedOperationException or something like that when user calls > CacheEntry.version(). Then, I imagine there would be only one place in the > code where the decision as to which implementation to use would have to be > made. Based on the value of Query's includeEntryVersion flag the code > would instantiate either one implementation class or another. That's it. > Am I oversimplifying? > > For my use case, I'm actually very interested in adding the entry version > support to the queries. The getEntry() came out of the realization that > Ignite doesn't currently provide any way to atomically obtain a cache value > along with its version. Truth be told, the EntryProcessor could also be > used as a last resort workaround, but given its current rather unfortunate > implementation, we decided against it. > > Regards > Andrey > > > From: [hidden email] > > Date: Mon, 21 Dec 2015 12:15:50 -0800 > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > To: [hidden email] > > > > Andrey, > > > > You got me thinking on whether I belong to the playful performance kids > > category, or to the old-fart consistency crowd :) > > > > I agree on the getEntry(…) suggestion, and I think it would be fairly > easy > > to implement, even for the new community members. As far as including > > version into query results, it seems like a larger undertaking, and seems > > like it may pollute the existing implementation with additional hacky > code > > branches. > > > > I suggest adding a ticket for the getEntry(…) method only for now. What > do > > you think? > > > > D. > > > > On Mon, Dec 21, 2015 at 10:19 AM, Andrey Kornev < > [hidden email]> > > wrote: > > > > > Couple of points. > > > > > > First, if it were up to me, I'd keep the API simple & consistent by > > > always providing the version as defined by Ignite's CacheEntry > interface, > > > regardless whether it's the query who produces the entry or a > specialized > > > method like getEntry(). Which node is going to consume the data -- a > > > "client" or "server" -- should not matter either. In this case, > however a > > > concern about perceived performance losses due to the version > overhead has > > > apparently trumped any API integrity and consistency concerns. > > > > > > Second, given the first point, here's what I think we could do to keep > > > everybody (the performance kids and the consistency/integrity > old-farts) > > > happy. ))) > > > > > > 1) getEntry(K) unconditionally always returns a valid version > regardless > > > whether it's called from a client or server. In fact, the only reason > to > > > ever use this method is to get the entry version. I'd even suggest > going > > > one step further and have the getEntry() method return Ignite's > CacheEntry > > > interface rather than JCache's Cache.Entry (only to be immediately > > > unwrapped to Ignite's CacheEntry). > > > > > > 2) for queries, provide an option on the Ignite's Query class (say, > > > setIncludeEntryVersion(boolean)) that would control whether the query > > > should send the version back. By default, it'd be "false" as to have no > > > impact on performance. More advanced users ;) would still be able to > enjoy > > > API consistency by setting that option to "true". > > > > > > Deal? > > > Andrey > > > > > > > From: [hidden email] > > > > Date: Mon, 21 Dec 2015 08:30:02 -0800 > > > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > > > To: [hidden email] > > > > > > > > On Mon, Dec 21, 2015 at 12:36 AM, Denis Magda <[hidden email]> > > > wrote: > > > > > > > > > > > > > > > > > > > On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > > > > > > > > > >> On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda < > [hidden email]> > > > > >> wrote: > > > > >> > > > > >> Why it shouldn't work? > > > > >>> If client receives an entry that has a reference to the entry > with > > > > >>> version, transferred from a server as well as a part of the > response, > > > > >>> then > > > > >>> unwrap(...) should work. > > > > >>> Isn't this feasible to implement? > > > > >>> > > > > >>> The reason is consistency. If getEntry(…) can be unwrapped on the > > > client > > > > >> side, then all the query results should be un-wrappable as well, > which > > > > >> means that we have to always carry the cache version, even if user > > > does > > > > >> not > > > > >> need it. > > > > >> > > > > > The proposal is to add getEntry(...) method exactly for the cases > when > > > > > someone needs an entry with a version on a client. > > > > > In all other cases (queries, etc.) the version won't be a part of a > > > > > response. > > > > > > > > > > Right, this is inconsistent but if to document everything well > then the > > > > > user will only benefit from the new getEntry(...) method. > > > > > CacheEntry with version is already can be unwrapped from specific > > > places > > > > > that are listed in its documentation. We will just broaden the > list. > > > > > > > > > > > > > Romain, Andrey, can you please comment? > > > > > > > > |
RE: Missing ways to get access to Ignite CacheEntry
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Ok, deal! And while we're at it could we add getAllEntries(Set<K>) as per Denis suggestion?
Thanks Andrey > From: [hidden email] > Date: Mon, 21 Dec 2015 15:24:44 -0800 > Subject: Re: Missing ways to get access to Ignite CacheEntry > To: [hidden email] > > Andrey, > > I think getEntry(…) can be done quickly. Adding another serialization > mechanism for cache entries together with a configuration flag may take > additional time. I would suggest, again, starting with getEntry method and > then moving down to queries. > > D. > > On Mon, Dec 21, 2015 at 1:04 PM, Andrey Kornev <[hidden email]> > wrote: > > > Personally, I'm firmly in the old-farts camp -- I like things consistent. > > :))) My motto is: get things right first, and then make them fast. > > > > As for the queries, I don't understand why do you think that supporting > > the version would mean adding lots of branching code? One would only have 2 > > implementations of Ignite's CacheEntry - one with the version field and > > another -- without. The latter would just throw an > > UnsupportedOperationException or something like that when user calls > > CacheEntry.version(). Then, I imagine there would be only one place in the > > code where the decision as to which implementation to use would have to be > > made. Based on the value of Query's includeEntryVersion flag the code > > would instantiate either one implementation class or another. That's it. > > Am I oversimplifying? > > > > For my use case, I'm actually very interested in adding the entry version > > support to the queries. The getEntry() came out of the realization that > > Ignite doesn't currently provide any way to atomically obtain a cache value > > along with its version. Truth be told, the EntryProcessor could also be > > used as a last resort workaround, but given its current rather unfortunate > > implementation, we decided against it. > > > > Regards > > Andrey > > > > > From: [hidden email] > > > Date: Mon, 21 Dec 2015 12:15:50 -0800 > > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > > To: [hidden email] > > > > > > Andrey, > > > > > > You got me thinking on whether I belong to the playful performance kids > > > category, or to the old-fart consistency crowd :) > > > > > > I agree on the getEntry(…) suggestion, and I think it would be fairly > > easy > > > to implement, even for the new community members. As far as including > > > version into query results, it seems like a larger undertaking, and seems > > > like it may pollute the existing implementation with additional hacky > > code > > > branches. > > > > > > I suggest adding a ticket for the getEntry(…) method only for now. What > > do > > > you think? > > > > > > D. > > > > > > On Mon, Dec 21, 2015 at 10:19 AM, Andrey Kornev < > > [hidden email]> > > > wrote: > > > > > > > Couple of points. > > > > > > > > First, if it were up to me, I'd keep the API simple & consistent by > > > > always providing the version as defined by Ignite's CacheEntry > > interface, > > > > regardless whether it's the query who produces the entry or a > > specialized > > > > method like getEntry(). Which node is going to consume the data -- a > > > > "client" or "server" -- should not matter either. In this case, > > however a > > > > concern about perceived performance losses due to the version > > overhead has > > > > apparently trumped any API integrity and consistency concerns. > > > > > > > > Second, given the first point, here's what I think we could do to keep > > > > everybody (the performance kids and the consistency/integrity > > old-farts) > > > > happy. ))) > > > > > > > > 1) getEntry(K) unconditionally always returns a valid version > > regardless > > > > whether it's called from a client or server. In fact, the only reason > > to > > > > ever use this method is to get the entry version. I'd even suggest > > going > > > > one step further and have the getEntry() method return Ignite's > > CacheEntry > > > > interface rather than JCache's Cache.Entry (only to be immediately > > > > unwrapped to Ignite's CacheEntry). > > > > > > > > 2) for queries, provide an option on the Ignite's Query class (say, > > > > setIncludeEntryVersion(boolean)) that would control whether the query > > > > should send the version back. By default, it'd be "false" as to have no > > > > impact on performance. More advanced users ;) would still be able to > > enjoy > > > > API consistency by setting that option to "true". > > > > > > > > Deal? > > > > Andrey > > > > > > > > > From: [hidden email] > > > > > Date: Mon, 21 Dec 2015 08:30:02 -0800 > > > > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > > > > To: [hidden email] > > > > > > > > > > On Mon, Dec 21, 2015 at 12:36 AM, Denis Magda <[hidden email]> > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > > > > > > > > > > > >> On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda < > > [hidden email]> > > > > > >> wrote: > > > > > >> > > > > > >> Why it shouldn't work? > > > > > >>> If client receives an entry that has a reference to the entry > > with > > > > > >>> version, transferred from a server as well as a part of the > > response, > > > > > >>> then > > > > > >>> unwrap(...) should work. > > > > > >>> Isn't this feasible to implement? > > > > > >>> > > > > > >>> The reason is consistency. If getEntry(…) can be unwrapped on the > > > > client > > > > > >> side, then all the query results should be un-wrappable as well, > > which > > > > > >> means that we have to always carry the cache version, even if user > > > > does > > > > > >> not > > > > > >> need it. > > > > > >> > > > > > > The proposal is to add getEntry(...) method exactly for the cases > > when > > > > > > someone needs an entry with a version on a client. > > > > > > In all other cases (queries, etc.) the version won't be a part of a > > > > > > response. > > > > > > > > > > > > Right, this is inconsistent but if to document everything well > > then the > > > > > > user will only benefit from the new getEntry(...) method. > > > > > > CacheEntry with version is already can be unwrapped from specific > > > > places > > > > > > that are listed in its documentation. We will just broaden the > > list. > > > > > > > > > > > > > > > > Romain, Andrey, can you please comment? > > > > > > > > > > > > |
Re: Missing ways to get access to Ignite CacheEntry
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Here is the ticket:
https://issues.apache.org/jira/browse/IGNITE-2224 On Mon, Dec 21, 2015 at 3:57 PM, Andrey Kornev <[hidden email]> wrote: > Ok, deal! And while we're at it could we add getAllEntries(Set<K>) as per > Denis suggestion? > > Thanks > Andrey > > > From: [hidden email] > > Date: Mon, 21 Dec 2015 15:24:44 -0800 > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > To: [hidden email] > > > > Andrey, > > > > I think getEntry(…) can be done quickly. Adding another serialization > > mechanism for cache entries together with a configuration flag may take > > additional time. I would suggest, again, starting with getEntry method > and > > then moving down to queries. > > > > D. > > > > On Mon, Dec 21, 2015 at 1:04 PM, Andrey Kornev <[hidden email] > > > > wrote: > > > > > Personally, I'm firmly in the old-farts camp -- I like things > consistent. > > > :))) My motto is: get things right first, and then make them fast. > > > > > > As for the queries, I don't understand why do you think that supporting > > > the version would mean adding lots of branching code? One would only > have 2 > > > implementations of Ignite's CacheEntry - one with the version field and > > > another -- without. The latter would just throw an > > > UnsupportedOperationException or something like that when user calls > > > CacheEntry.version(). Then, I imagine there would be only one place in > the > > > code where the decision as to which implementation to use would have > to be > > > made. Based on the value of Query's includeEntryVersion flag the code > > > would instantiate either one implementation class or another. That's > it. > > > Am I oversimplifying? > > > > > > For my use case, I'm actually very interested in adding the entry > version > > > support to the queries. The getEntry() came out of the realization that > > > Ignite doesn't currently provide any way to atomically obtain a cache > value > > > along with its version. Truth be told, the EntryProcessor could also be > > > used as a last resort workaround, but given its current rather > unfortunate > > > implementation, we decided against it. > > > > > > Regards > > > Andrey > > > > > > > From: [hidden email] > > > > Date: Mon, 21 Dec 2015 12:15:50 -0800 > > > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > > > To: [hidden email] > > > > > > > > Andrey, > > > > > > > > You got me thinking on whether I belong to the playful performance > kids > > > > category, or to the old-fart consistency crowd :) > > > > > > > > I agree on the getEntry(…) suggestion, and I think it would be fairly > > > easy > > > > to implement, even for the new community members. As far as including > > > > version into query results, it seems like a larger undertaking, and > seems > > > > like it may pollute the existing implementation with additional hacky > > > code > > > > branches. > > > > > > > > I suggest adding a ticket for the getEntry(…) method only for now. > What > > > do > > > > you think? > > > > > > > > D. > > > > > > > > On Mon, Dec 21, 2015 at 10:19 AM, Andrey Kornev < > > > [hidden email]> > > > > wrote: > > > > > > > > > Couple of points. > > > > > > > > > > First, if it were up to me, I'd keep the API simple & consistent > by > > > > > always providing the version as defined by Ignite's CacheEntry > > > interface, > > > > > regardless whether it's the query who produces the entry or a > > > specialized > > > > > method like getEntry(). Which node is going to consume the data -- > a > > > > > "client" or "server" -- should not matter either. In this case, > > > however a > > > > > concern about perceived performance losses due to the version > > > overhead has > > > > > apparently trumped any API integrity and consistency concerns. > > > > > > > > > > Second, given the first point, here's what I think we could do to > keep > > > > > everybody (the performance kids and the consistency/integrity > > > old-farts) > > > > > happy. ))) > > > > > > > > > > 1) getEntry(K) unconditionally always returns a valid version > > > regardless > > > > > whether it's called from a client or server. In fact, the only > reason > > > to > > > > > ever use this method is to get the entry version. I'd even suggest > > > going > > > > > one step further and have the getEntry() method return Ignite's > > > CacheEntry > > > > > interface rather than JCache's Cache.Entry (only to be immediately > > > > > unwrapped to Ignite's CacheEntry). > > > > > > > > > > 2) for queries, provide an option on the Ignite's Query class (say, > > > > > setIncludeEntryVersion(boolean)) that would control whether the > query > > > > > should send the version back. By default, it'd be "false" as to > have no > > > > > impact on performance. More advanced users ;) would still be able > to > > > enjoy > > > > > API consistency by setting that option to "true". > > > > > > > > > > Deal? > > > > > Andrey > > > > > > > > > > > From: [hidden email] > > > > > > Date: Mon, 21 Dec 2015 08:30:02 -0800 > > > > > > Subject: Re: Missing ways to get access to Ignite CacheEntry > > > > > > To: [hidden email] > > > > > > > > > > > > On Mon, Dec 21, 2015 at 12:36 AM, Denis Magda < > [hidden email]> > > > > > wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > > On 12/21/2015 11:15 AM, Dmitriy Setrakyan wrote: > > > > > > > > > > > > > >> On Mon, Dec 21, 2015 at 12:11 AM, Denis Magda < > > > [hidden email]> > > > > > > >> wrote: > > > > > > >> > > > > > > >> Why it shouldn't work? > > > > > > >>> If client receives an entry that has a reference to the entry > > > with > > > > > > >>> version, transferred from a server as well as a part of the > > > response, > > > > > > >>> then > > > > > > >>> unwrap(...) should work. > > > > > > >>> Isn't this feasible to implement? > > > > > > >>> > > > > > > >>> The reason is consistency. If getEntry(…) can be unwrapped > on the > > > > > client > > > > > > >> side, then all the query results should be un-wrappable as > well, > > > which > > > > > > >> means that we have to always carry the cache version, even if > user > > > > > does > > > > > > >> not > > > > > > >> need it. > > > > > > >> > > > > > > > The proposal is to add getEntry(...) method exactly for the > cases > > > when > > > > > > > someone needs an entry with a version on a client. > > > > > > > In all other cases (queries, etc.) the version won't be a part > of a > > > > > > > response. > > > > > > > > > > > > > > Right, this is inconsistent but if to document everything well > > > then the > > > > > > > user will only benefit from the new getEntry(...) method. > > > > > > > CacheEntry with version is already can be unwrapped from > specific > > > > > places > > > > > > > that are listed in its documentation. We will just broaden the > > > list. > > > > > > > > > > > > > > > > > > > Romain, Andrey, can you please comment? > > > > > > > > > > > > > > > > > > |
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