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Posted to user@cassandra.apache.org by Alain Rastoul <al...@gmail.com> on 2017/08/18 21:41:32 UTC

Cassandra-count gives wrong results

Hi,

I use cassandra-count (github 
https://github.com/brianmhess/cassandra-count) to count records in a 
table, but I have wrong results.

When I export data with cqlsh /copy to csv, I have 1M records in my test 
table, when I use cassandra-count I have different results for each node :
build/cassandra-count -host cstar1 -user cassandra -pw cassandra 
-keyspace metrics -table datapoints
metrics.datapoints: 379285

build/cassandra-count -host cstar2 -user cassandra -pw cassandra 
-keyspace metrics -table datapoints
metrics.datapoints: 324856

build/cassandra-count -host cstar3 -user cassandra -pw cassandra 
-keyspace metrics -table datapoints
metrics.datapoints: 340615

It used to work in previous runs, but suddenly, the results went  wrong, 
I can't understand why.

I downloaded the cassandra-count project, built and debugged it, but 
still can't understand.

the program reads partitions in system.size_estimates, then for each 
partition execute
SELECT COUNT(*) FROM keyspaceName.tableName WHERE Token("path") > ? AND 
Token("path") <= ?
with start and end ranges.
The ring is correct, each node has the same ring.


Any clue about this ?

TIA


-- 
best,
Alain


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