When the cluster loses all copies of a partition the behavior is defined by PartitionLossPolicy. The current default is IGNORE which is indeed an AP rather than CP option. You can set it to READ_WRITE_SAFE or READ_ONLY_SAFE to get the CP behavior. I would also strongly advise to do so if you use native persistence as there are issues with IGNORE in that mode.
There also was a bug that prevented SQL from handling partition loss correctly. It was fixed for in-memory in 2.7 and for persistence in 2.8. Stan > On 24 Dec 2018, at 09:55, joseheitor <j...@heitorprojects.com> wrote: > > In this GridGain presentation: > > https://www.youtube.com/watch?v=u8BFLDfOdy8&t=1806s > <https://www.youtube.com/watch?v=u8BFLDfOdy8&t=1806s> > > Valentin Kulichenko explains the CAP theorem and states that Apache Ignite > is designed to favour Strong-Consistency (CP) over High-Availability (AP). > > However, in my test case, my system appears to be behaving as an AP system. > Here is my setup: > > 4 partitioned nodes in 2 availability-zones [AZa-1, AZa-2] [AZb-3, AZb-4], > configured as described in this post: > > http://apache-ignite-users.70518.x6.nabble.com/RESOLVED-Cluster-High-Availability-tp25740.html > <http://apache-ignite-users.70518.x6.nabble.com/RESOLVED-Cluster-High-Availability-tp25740.html> > > > With 7,000 records loaded into a table in the cluster with JDBC Thin client: > > 1. [OK] I can connect to any node and verify that there are 7,000 records > with a SELECT COUNT(*) > > 2. [OK] If I kill all nodes in AZ-a [AZa-1, AZa-2], and connect to one of > the remaining online nodes in AZ-b, I can still verify that there are 7,000 > records with a SELECT COUNT(*) > > 3. [?] I then kill one of the remaining two nodes in AZ-b and connect to the > single remaining node. Now a SELECT COUNT(*) returns a value of 3,444 > records. > > This seems to illustrate that the partitioning and backup configuration is > working as intended. But if Ignite is strongly-consistent (CP), shouldn't > the final query fail rather than return an inaccurate result (AP)? > > Or am I missing some crucial configuration element(s)? > > > > -- > Sent from: http://apache-ignite-users.70518.x6.nabble.com/
