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cassandrahector

Health check for Cassandra connection (using hector)?

For operations monitoring of my application, I am looking for something similar to the commonly used "SQL connection validation" query

SELECT 1;

in Cassandra, using the Hector driver. I have tried things like looking at Cluster.getKnownPoolHosts() and .getConnectionManager().getActivePools(). But it seems that their status is not continuously updated, only when I actually try to access Cassandra with a query.

I'd like my health check to be independent of any keyspaces or user CFs that need to exist, so just running a "dummy" query seems difficult (against what?). And of course it shouldn't take a lot of memory or generate any significant load.

Can I force Hector somehow to update its connection pool status without running a real query?

(BTW: CQL doesn't even accept "SELECT 1" as a valid query.)

Solution

  • The solution I'm currently using, and which seems to be the most robust so far (tested with Cassandra 1.1 and 1.2) is a simple query on "system":

    Query<String> query = Query.selectQuery("*", "system", null, 1, consistencyLevel, StringSerializer.get());

    It's not exactly what I wanted since it's a "real" query, but on the other hand it doesn't give any false positives.