The main overhead is that each table locks 1MB of Java heap, so if you have 1000 tables it will use 1GB of RAM just for managing the tables, even if they are empty.
-- Jacques-Henri Berthemet From: Alaa Zubaidi (PDF) [mailto:alaa.zuba...@pdf.com] Sent: Friday, February 16, 2018 1:05 AM To: user@cassandra.apache.org; Dinesh Joshi <dinesh.jo...@yahoo.com> Subject: Re: overhead of empty tables Thanks Dinesh, We have 36332 files under the data folder On Thu, Feb 15, 2018 at 3:45 PM, Dinesh Joshi <dinesh.jo...@yahoo.com.invalid<mailto:dinesh.jo...@yahoo.com.invalid>> wrote: Each table in a keyspace is stored as a separate directory in the data directory. If you many tables you'll have a lot of files. Some file systems have issues dealing with a lot of files in a single directory. Other than that, there will likely be some book keeping overhead within the Cassandra process. How many tables are we talking about here? Here's more information about it: https://docs.datastax.com/en/cassandra/3.0/cassandra/dml/dmlHowDataWritten.html<https://docs.datastax.com/en/cassandra/3.0/cassandra/dml/dmlHowDataWritten.html> Dinesh On Thursday, February 15, 2018, 3:34:49 PM PST, Alaa Zubaidi (PDF) <alaa.zuba...@pdf.com<mailto:alaa.zuba...@pdf.com>> wrote: Is there any overhead if my keyspace contains many empty tables? Thanks Alaa This message may contain confidential and privileged information. If it has been sent to you in error, please reply to advise the sender of the error and then immediately permanently delete it and all attachments to it from your systems. If you are not the intended recipient, do not read, copy, disclose or otherwise use this message or any attachments to it. The sender disclaims any liability for such unauthorized use. PLEASE NOTE that all incoming e-mails sent to PDF e-mail accounts will be archived and may be scanned by us and/or by external service providers to detect and prevent threats to our systems, investigate illegal or inappropriate behavior, and/or eliminate unsolicited promotional e-mails (“spam”). If you have any concerns about this process, please contact us at legal.departm...@pdf.com<mailto:legal.departm...@pdf.com>. -- Alaa Zubaidi PDF Solutions, Inc. 333 West San Carlos Street, Suite 1000 San Jose, CA 95110 USA Tel: 408-283-5639 fax: 408-938-6479 email: alaa.zuba...@pdf.com<mailto:alaa.zuba...@pdf.com> This message may contain confidential and privileged information. If it has been sent to you in error, please reply to advise the sender of the error and then immediately permanently delete it and all attachments to it from your systems. If you are not the intended recipient, do not read, copy, disclose or otherwise use this message or any attachments to it. The sender disclaims any liability for such unauthorized use. PLEASE NOTE that all incoming e-mails sent to PDF e-mail accounts will be archived and may be scanned by us and/or by external service providers to detect and prevent threats to our systems, investigate illegal or inappropriate behavior, and/or eliminate unsolicited promotional e-mails (“spam”). If you have any concerns about this process, please contact us at legal.departm...@pdf.com<mailto:legal.departm...@pdf.com>.
