Hello there,

We are experimenting Counters in Cassandra 2.2.5. Our setup is that we have
6 nodes, across three different regions, and in each region, the
replication factor is 2. Basically, each nodes holds a full copy of the
data.

When are doing 30k/s counter increment/decrement per node, and at the
meanwhile, we are double writing to our mysql tier, so that we can measure
the accuracy of C* counter, compared to mysql.

The experiment result was great at the beginning, the counter value in C*
and mysql are very close. The difference is less than 0.1%.

But when we start to run the repair on one node, the counter value in C*
become much less than the value in mysql,  the difference becomes larger
than 1%.

My question is that is it a known problem that the counter value will
become under-counted if repair is running? Should we avoid running repair
for counter tables?

Thanks.

-- 
Dikang

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