Seems that this.getClass().hashCode() executed on different VMs can produce different result (but it should always produce the same result on a single VM which doesn’t violate JVM specification). Ignite requires the hashCode of a key to be consistent cluster-wide. So Ignite has even more stronger requirement then JVM spec.
— Denis > On Jun 23, 2016, at 11:30 AM, Kristian Rosenvold <krosenv...@apache.org> > wrote: > > We think the issue may regard transportability of the hashCode across > nodes, because the hashcode in question included the hashcode of a > class (in other words this.getClass().hashCode() as opposed to the > more robust this.getClass().getName().hashCode()) > > Does ignite require the hashCode of a key to be cluster-wide consistent ? > > (This would actually be a violation of the javadoc contract for > hashcode, which states "This integer need not remain consistent from > one execution of an application to another execution of the same > application.". But it should possible to actually test for this if it > is a constraint required by ignite.) > > If this does not appear to be the problem, I can supply the code in question. > > Kristian > > > > 2016-06-23 10:05 GMT+02:00 Denis Magda <dma...@gridgain.com>: >> Hi Kristian, >> >> Could you share the source of a class that has inconsistent equals/hashCode >> implementation? Probably we will be able to detect your case internally >> somehow and print a warning. >> >> — >> Denis >> >>> On Jun 17, 2016, at 10:27 PM, Kristian Rosenvold <krosenv...@apache.org> >>> wrote: >>> >>> This whole issue was caused by inconsistent equals/hashCode on a cache >>> key, which appearantly has the capability of stopping replication dead >>> in its tracks. Nailing this one after 3-4 days of a very nagging >>> "select is broken" feeling was great. You guys helping us here might >>> want to be particularly aware of this, since it undeniably gives a newbie an >>> impression that ignite is broken while it's my code :) >>> >>> Thanks for the help ! >>> >>> Kristian >>> >>> >>> 2016-06-17 20:00 GMT+02:00 Alexey Goncharuk <alexey.goncha...@gmail.com>: >>>> Kristian, >>>> >>>> Are you sure you are using the latest 1.7-SNAPSHOT for your production >>>> data? >>>> Did you build binaries yourself? Can you confirm the commit# of the >>>> binaries >>>> you are using? The issue you are reporting seems to be the same as >>>> IGNITE-3305 and, since the fix was committed only a couple of days ago, it >>>> might not get to nightly snapshot. >>>> >>>> 2016-06-17 9:06 GMT-07:00 Kristian Rosenvold <krosenv...@apache.org>: >>>>> >>>>> Sigh, this has all the hallmarks of a thread safety issue or race >>>>> condition. >>>>> >>>>> I had a perfect testcase that replicated the problem 100% of the time, >>>>> but only when running on distinct nodes (never occurs on same box) >>>>> with 2 distinct caches and with ignite 1.5; I just expanded the >>>>> testcase I posted initially . Typically I'd be missing the last 10-20 >>>>> elements in the cache. I was about 2 seconds from reporting an issue >>>>> and then I switched to yesterday's 1.7-SNAPSHOT version and it went >>>>> away. Unfortunately 1.7-SNAPSHOT exhibits the same behaviour with my >>>>> production data, it just broke my testcase :( Assumably I just need to >>>>> tweak the cache sizes or element counts to hit some kind of non-sweet >>>>> spot, and then it probably fails on my machine. >>>>> >>>>> The testcase always worked on a single box, which lead me to think >>>>> about socket-related issues. But it also required 2 caches to fail, >>>>> which lead me to think about race conditions like the rebalance >>>>> terminating once the first node finishes. >>>>> >>>>> I'm no stranger to reading bug reports like this myself, and I must >>>>> admit this seems pretty tough to diagnose. >>>>> >>>>> Kristian >>>>> >>>>> >>>>> 2016-06-17 14:57 GMT+02:00 Denis Magda <dma...@gridgain.com>: >>>>>> Hi Kristian, >>>>>> >>>>>> Your test looks absolutely correct for me. However I didn’t manage to >>>>>> reproduce this issue on my side as well. >>>>>> >>>>>> Alex G., do you have any ideas on what can be a reason of that? Can you >>>>>> recommend Kristian enabling of DEBUG/TRACE log levels for particular >>>>>> modules? Probably advanced logging will let us to pin point the issue >>>>>> that >>>>>> happens in Kristian’s environment. >>>>>> >>>>>> — >>>>>> Denis >>>>>> >>>>>> On Jun 17, 2016, at 10:02 AM, Kristian Rosenvold <krosenv...@apache.org> >>>>>> wrote: >>>>>> >>>>>> For ignite 1.5, 1.6 and 1.7-SNAPSHOT, I see the same behaviour. Since >>>>>> REPLICATED caches seem to be broken on 1.6 and beyond, I am testing >>>>>> this on 1.5: >>>>>> >>>>>> I can reliably start two nodes and get consistent correct results, >>>>>> lets say each node has 1.5 million elements in a given cache. >>>>>> >>>>>> Once I start a third or fourth node in the same cluster, it >>>>>> consistently gets a random incorrect number of elements in the same >>>>>> cache, typically 1.1 million or so. >>>>>> >>>>>> I tried to create a testcase to reproduce this on my local machine >>>>>> >>>>>> (https://github.com/krosenvold/ignite/commit/4fb3f20f51280d8381e331b7bcdb2bae95b76b95), >>>>>> but this fails to reproduce the problem. >>>>>> >>>>>> I have two nodes in 2 different datacenters, so there will invariably >>>>>> be some differences in latencies/response times between the existing 2 >>>>>> nodes and the newly started node. >>>>>> >>>>>> This sounds like some kind of timing related bug, any tips ? Is there >>>>>> any way I kan skew the timing in the testcase ? >>>>>> >>>>>> >>>>>> Kristian >>>>>> >>>>>> >>>> >>>> >>