I think bad effect #1 needs clarification.
This only suspends minor compactions involving that 1 big file. As new sstables are flushed, they are of the same small size and they will eventually compact together. So that one big file will sit idle (as far as compaction go) until you build some eventualluy compact the new files into ones as big as tht major compacted sstable. That is why those who do major compactions once normally end up doing them periodically to cause compaction with the previous large sstable.
I hope this helps,jc
Bad effects are :
1 - Disabling for a *long* time your minor compactions (they need SSTable about the same size to be triggered).2 - High cpu load during the compaction (which can be quite long).
Good effects :
1 - Reduce the size of your data.2 - Boost read performances.
@B. Todd Burruss
What can we do if cleanup doesn't remove any data and so doesn't balance the data partition ?We both have well balanced ring and unbalanced data...
2012/10/11 Viktor Jevdokimov <Viktor.Jevdokimov@adform.com>
In our case, we use TTL and need to keep amount of data as low as possible to fit RAM, so data have to be deleted somehow.
While SSTables are growing, largest will wait long time for minor compaction, so we do major compaction every night.
Best regards / PagarbiaiViktor JevdokimovSenior Developer
Email: Viktor.Jevdokimov@adform.comJ. Jasinskio 16C, LT-01112 Vilnius, LithuaniaFollow us on Twitter: @adforminsiderWhat is Adform: watch this short video
Visit us at IAB RTB workshopOctober 11, 4 pm in Sala Rossa
Disclaimer: The information contained in this message and attachments is intended solely for the attention and use of the named addressee and may be confidential. If you are not the intended recipient, you are reminded that the information remains the property of the sender. You must not use, disclose, distribute, copy, print or rely on this e-mail. If you have received this message in error, please contact the sender immediately and irrevocably delete this message and any copies.