Thanks for the pointer. I had never heard of this. While it seems that it could help, I think our rules for determining which records to keep are not supported. Also, this requires adding a new jar to production. Too risky at this point.
Sean Durity From: Jon Haddad [mailto:jonathan.had...@gmail.com] On Behalf Of Jon Haddad Sent: Thursday, September 21, 2017 2:59 PM To: user <user@cassandra.apache.org> Subject: Re: Massive deletes -> major compaction? Have you considered the fantastic DeletingCompactionStrategy? https://github.com/protectwise/cassandra-util/tree/master/deleting-compaction-strategy<https://urldefense.proofpoint.com/v2/url?u=https-3A__github.com_protectwise_cassandra-2Dutil_tree_master_deleting-2Dcompaction-2Dstrategy&d=DwMFaQ&c=MtgQEAMQGqekjTjiAhkudQ&r=aC_gxC6z_4f9GLlbWiKzHm1vucZTtVYWDDvyLkh8IaQ&m=XbpSdVHHLZeNv3mp3UkL122S3UryXjaG-ROk8SK6Oro&s=rP7k5CqnOsEASTayoqmU-BOCfo-R0tqg6VGBc3sSXoE&e=> On Sep 21, 2017, at 11:51 AM, Jeff Jirsa <jji...@gmail.com<mailto:jji...@gmail.com>> wrote: The major compaction is most efficient but can temporarily double (nearly) disk usage - if you can afford that, go for it. Alternatively you can do a user-defined compaction on each sstable in reverse generational order (oldest first) and as long as the data is minimally overlapping it’ll purge tombstones that way as well - takes longer but much less disk involved. -- Jeff Jirsa On Sep 21, 2017, at 11:27 AM, Durity, Sean R <sean_r_dur...@homedepot.com<mailto:sean_r_dur...@homedepot.com>> wrote: Cassandra version 2.0.17 (yes, it’s old – waiting for new hardware/new OS to upgrade) In a long-running system with billions of rows, TTL was not set. So a one-time purge is being planned to reduce disk usage. Records older than a certain date will be deleted. The table uses size-tiered compaction. Deletes are probably 25-40% of the complete data set. To actually recover the disk space, would you recommend a major compaction after the gc_grace_seconds time? I expect compaction would then need to be scheduled regularly (ick)… We also plan to re-insert the remaining data with a calculated TTL, which could also benefit from compaction. Sean Durity ________________________________ The information in this Internet Email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this Email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. When addressed to our clients any opinions or advice contained in this Email are subject to the terms and conditions expressed in any applicable governing The Home Depot terms of business or client engagement letter. The Home Depot disclaims all responsibility and liability for the accuracy and content of this attachment and for any damages or losses arising from any inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other items of a destructive nature, which may be contained in this attachment and shall not be liable for direct, indirect, consequential or special damages in connection with this e-mail message or its attachment. ________________________________ The information in this Internet Email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this Email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. When addressed to our clients any opinions or advice contained in this Email are subject to the terms and conditions expressed in any applicable governing The Home Depot terms of business or client engagement letter. The Home Depot disclaims all responsibility and liability for the accuracy and content of this attachment and for any damages or losses arising from any inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other items of a destructive nature, which may be contained in this attachment and shall not be liable for direct, indirect, consequential or special damages in connection with this e-mail message or its attachment.
