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From "Ahmed Ferdous" <Ahmed.Ferd...@ze.com>
Subject RE: Configuring Cassandra to limit number of columns to read
Date Fri, 14 Aug 2015 18:35:08 GMT
My mistake. I wanted to mean column keys. For each row, we have one column and for this column
we have 250k+ column keys. When we are trying to load the list of column keys , Cassandra
is having OOM error.

Ahmed






Ahmed Ferdous

Systems Architect

ZE PowerGroup Inc.

Corporate: 604-244-1469

From: Russell Bradberry [mailto:rbradberry@gmail.com]
Sent: August-14-15 11:20 AM
To: user@cassandra.apache.org
Subject: Re: Configuring Cassandra to limit number of columns to read

The idea that you have 250k columns is somewhat of an anti-pattern.  In this case you would
typically have a few columns and many rows, then just run a select with a limit clause in
your partition.

From: Jonathan Haddad
Reply-To: <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Date: Friday, August 14, 2015 at 2:16 PM
To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>"
Subject: Re: Configuring Cassandra to limit number of columns to read

250k columns?    As in, you have a CREATE TABLE statement that would have over 250K separate,
typed fields?

On Fri, Aug 14, 2015 at 11:07 AM Ahmed Ferdous <Ahmed.Ferdous@ze.com<mailto:Ahmed.Ferdous@ze.com>>
wrote:
Hi Guys,

We have designed a table to have rows with large number of columns (more than 250k). One of
my colleagues, mistakenly ran a select on the  and that caused the nodes to go out of memory.
I was just wondering if there are ways to configure Cassandra 1. To limit number of columns
that can be read 2. To gracefully reject a read request if it appears to be consuming a lot
of memory. Otherwise, we are leaving too much open to human mistakes.

Cheers,

Ahmed



________________________________

Ahmed Ferdous
Systems Architect
Corporate: 604-244-1469     Email: Ahmed.Ferdous@ze.com<mailto:Ahmed.Ferdous@ze.com>

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