Slava, >> I will take a look at your pull request if you don't mind. Great news!
>> In any way, could you please update the IEP page with the list of >> constraints/limitations of the proposed approach, TODOs, etc? Not sure we should keep this at IEP until list (#4 from original letter) is not confirmed. Currently, I'm checking RunAll with RR enabled to almost each get request. "Almost" means: readRepair = !ctx.readThrough() && ctx.config().getBackups() > 0 && !ctx.isNear() && !ctx.mvccEnabled() For now I have 60 failed tests and amount decreasing. >> For instance, I would like to see all these limitations on the IEP page as >> JIRA tickets. Perhaps, it would be good to create an epic/umbrella ticket >> in order to track all activities related to `Read Repair` feature. Let's do this at merge day to be sure useless issues will not be created. On Fri, Jun 28, 2019 at 2:01 PM Вячеслав Коптилин <slava.kopti...@gmail.com> wrote: > Hi Anton, > > I will take a look at your pull request if you don't mind. > > In any way, could you please update the IEP page with the list of > constraints/limitations of the proposed approach, TODOs, etc? > For instance, I would like to see all these limitations on the IEP page as > JIRA tickets. Perhaps, it would be good to create an epic/umbrella ticket > in order to track all activities related to `Read Repair` feature. > > Thanks, > S. > > чт, 20 июн. 2019 г. в 14:15, Anton Vinogradov <a...@apache.org>: > > > Igniters, > > I'm glad to introduce Read Repair feature [0] provides additional > > consistency guarantee for Ignite. > > > > 1) Why we need it? > > The detailed explanation can be found at IEP-31 [1]. > > In short, because of bugs, it's possible to gain an inconsistent state. > > We need additional features to handle this case. > > > > Currently we able to check cluster using Idle_verify [2] feature, but it > > will not fix the data, will not even tell which entries are broken. > > Read Repair is a feature to understand which entries are broken and to > fix > > them. > > > > 1) How it works? > > IgniteCache now able to provide special proxy [3] withReadRepair(). > > This proxy guarantee that data will be gained from all owners and > compared. > > In the case of consistency violation situation, data will be recovered > and > > a special event recorded. > > > > 3) Naming? > > Feature name based on Cassandra's Read Repair feature [4], which is > pretty > > similar. > > > > 4) Limitations which can be fixed in the future? > > * MVCC and Near caches are not supported. > > * Atomic caches can be checked (false positive case is possible on this > > check), but can't be recovered. > > * Partial entry removal can't be recovered. > > * Entries streamed using data streamer (using not a "cache.put" based > > updater) and loaded by cache.load > > are perceived as inconsistent since they may have different versions > for > > same keys. > > * Only explicit get operations are supported (getAndReplace, getAndPut, > > etc can be supported in future). > > > > 5) What's left? > > * SQL/ThinClient/etc support. > > * Metrics (found/repaired). > > * Simple per-partition recovery feature able to work in the background > in > > addition to per-entry recovery feature. > > > > 6) Is code checked? > > * Pull Request #5656 [5] (feature) - has green TC. > > * Pull Request #6575 [6] (RunAll with the feature enabled for every > get() > > request) - has a limited amount of failures (because of data streamer, > > cache.load, etc). > > > > Thoughts? > > > > [0] https://issues.apache.org/jira/browse/IGNITE-10663 > > [1] > > > > > https://cwiki.apache.org/confluence/display/IGNITE/IEP-31+Consistency+check+and+fix > > [2] > > > > > https://apacheignite-tools.readme.io/docs/control-script#section-verification-of-partition-checksums > > [3] > > > > > https://github.com/apache/ignite/blob/27b6105ecc175b61e0aef59887830588dfc388ef/modules/core/src/main/java/org/apache/ignite/IgniteCache.java#L140 > > [4] > > > > > https://docs.datastax.com/en/archived/cassandra/3.0/cassandra/operations/opsRepairNodesReadRepair.html > > [5] https://github.com/apache/ignite/pull/5656 > > [6] https://github.com/apache/ignite/pull/6575 > > >
