Hi,
We normally use a single data center, but when switching from one to another we
will temporarily have two. The applications works with the local DC part of the
cluster.
Normally the configuration of the driver would contain (the commented lines
absent):
.withLoadBalancingPolicy(DCAwareRoundRobinPolicy.builder()
.withLocalDc(localDataCenter)
// .withUsedHostsPerRemoteDc(3)
// .allowRemoteDCsForLocalConsistencyLevel()
.build())
However, the queries returned empty. Uncommenting the lines, the queries
returned data. Multiple runs on multiple apps in multiple locations/dcs, gave
data with lines commented/absent.
All these apps connect to a cassandra cluster within a single data center
currently. We are not clear why the empty results happened. Do you have any
idea what might have caused this?
Having the commented lines uncommented is dangerous in the context of how the
data center migration is planned, since the queries would be able to reach the
remote nodes which are not having all the data initially.
Please advise,
Thanks,
Nicu Marasoiu
Geschäftsanschrift/Business address: METRO SYSTEMS GmbH, Metro-Straße 12, 40235
Düsseldorf, Germany
Aufsichtsrat/Supervisory Board: Heiko Hutmacher (Vorsitzender/ Chairman)
Geschäftsführung/Management Board: Dr. Dirk Toepfer (Vorsitzender/CEO), Wim van
Herwijnen
Sitz Düsseldorf, Amtsgericht Düsseldorf, HRB 18232/Registered Office
Düsseldorf, Commercial Register of the Düsseldorf Local Court, HRB 18232
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