I faced the same nuance in my early days with C*, specifically I got RPC
timeouts on selecting data from CFs larger than 300 GB.
The typical remedy is to implement paging. So instead of using the CLI resort
to a custom built client app.
Regards,
Arthur
From: shahab
Sent: Wednesday, March 26, 2014 4:34 AM
To: user@cassandra.apache.org
Subject: Re: Why "select count("*) from .." hangs ?
Thanks for the hints. I got a better picture of how to deal with "count"
queries.
On Tue, Mar 25, 2014 at 7:01 PM, Robert Coli <rc...@eventbrite.com> wrote:
On Tue, Mar 25, 2014 at 8:36 AM, shahab <shahab.mok...@gmail.com> wrote:
But after iteration 8, (i.e. inserting 1500000 sensor data), the "select
count(') ...) throws time-out exception and doesn't work anymore. I even tried
to execute "select count(*)..." using Datastax DevCenter GUI, but I got same
result.
All operations in Cassandra are subject to (various) timeouts, which by
default are in the scale of single digit seconds.
If you attempt to do an operation (such as aggregates across large numbers of
large objects) which cannot complete in this time, this is a strong indication
that either your overall approach is inappropriate or, at very least, that your
buckets are too large.
=Rob
