Hmmmm, I thought bloomfilters only help on missing rows. Any time we look up a row, we know it is there in our case as it would not be in the other table. I would say statistically 99.9% of the time the row is there and we are okay with 0.1% of the time wasting hitting the disk.
Do I have this correct though? Bloomfilters really only help me if the data is not there so I don't have to go to the disk and find that out. Thanks, Dean From: aaron morton <aa...@thelastpickle.com<mailto:aa...@thelastpickle.com>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Date: Sunday, February 24, 2013 7:09 PM To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>> Subject: Re: disabling bloomfilter not working? or did I do this wrong? Yeah, disabling completely is probably not great. There is some wriggle room between disabled and "less memory" Did I link to this bloom filter calculator ? http://hur.st/bloomfilter also https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/utils/BloomCalculations.java Cheers ----------------- Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com On 23/02/2013, at 12:10 PM, Bryan Talbot <btal...@aeriagames.com<mailto:btal...@aeriagames.com>> wrote: I see from your read and write count that your nreldata CF has nearly equal number of reads as writes. I would expect that disabling your bloom filter is going to hurt your read performance quite a bit. Also, beware that disabling your bloom filter may also cause tombstoned rows to never be deleted, so if you delete all columns explicitly or use TTL, your data may grow more than your expect. https://issues.apache.org/jira/browse/CASSANDRA-5182 -Bryan On Fri, Feb 22, 2013 at 11:59 AM, Hiller, Dean <dean.hil...@nrel.gov<mailto:dean.hil...@nrel.gov>> wrote: Thanks, but I found out it is still running. It looks like I have about a 5 hour wait left for my upgradesstables(waited 4 hours already). I will check the bloomfilter after that. Out of curiosity, if I had much wider rows (ie. < 900k) per row, will compaction run faster(errrr…upgradesstables) at all or would it basically run at the same speed. I guess what I am wondering is 9 hours a normal compaction time for 130gb of data? Thanks, Dean From: aaron morton <aa...@thelastpickle.com<mailto:aa...@thelastpickle.com><mailto:aa...@thelastpickle.com<mailto:aa...@thelastpickle.com>>> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>> Date: Friday, February 22, 2013 10:29 AM To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org><mailto:user@cassandra.apache.org<mailto:user@cassandra.apache.org>>> Subject: Re: disabling bloomfilter not working? or did I do this wrong? Bloom Filter Space Used: 2318392048<tel:2318392048> Just to be sane do a quick check of the -Filter.db files on disk for this CF. If they are very small try a restart on the node. Number of Keys (estimate): 1249133696 Hey a billion rows on a node, what an age we live in :) Cheers ----------------- Aaron Morton Freelance Cassandra Developer New Zealand @aaronmorton http://www.thelastpickle.com<http://www.thelastpickle.com/> On 23/02/2013, at 4:35 AM, "Hiller, Dean" <dean.hil...@nrel.gov<mailto:dean.hil...@nrel.gov><mailto:dean.hil...@nrel.gov<mailto:dean.hil...@nrel.gov>>> wrote: So in the cli, I ran update column family nreldata with bloom_filter_fp_chance=1.0; Then I ran nodetool upgradesstables databus5 nreldata; But my bloom filter size is still around 2gig(and I want to free up this heap)!!!! According to nodetool cfstats command… Column Family: nreldata SSTable count: 10 Space used (live): 96841497731 Space used (total): 96841497731 Number of Keys (estimate): 1249133696 Memtable Columns Count: 7066 Memtable Data Size: 4286174 Memtable Switch Count: 924 Read Count: 19087150 Read Latency: 0.595 ms. Write Count: 21281994 Write Latency: 0.013 ms. Pending Tasks: 0 Bloom Filter False Postives: 974393 Bloom Filter False Ratio: 0.99998 Bloom Filter Space Used: 2318392048 Compacted row minimum size: 73 Compacted row maximum size: 446 Compacted row mean size: 143
