I think my impression that Bloom Filters were off in 1.1.9 was a misinterpretation of this thread:
http://www.mail-archive.com/user@cassandra.apache.org/msg27787.html and this bug: https://issues.apache.org/jira/browse/CASSANDRA-5029 I read it that Bloom filters were added to 1.2.2 for Bloomfilters, but apparently after being shutoff in an earlier version of 1.2? -Mike On Mar 7, 2013, at 4:48 PM, Edward Capriolo wrote: > I read that the change was made because Cassandra does not work well when > they are off. This makes sense because cassandra uses bloom filters to decide > if a row can be deleted without major compaction. However since LCS does not > major compact without bloom filters you can end up in cases where rows never > get deleted. > > Edward > > On Thu, Mar 7, 2013 at 4:30 PM, Wei Zhu <wz1...@yahoo.com> wrote: > Where did you read that bloom filters are off for LCS on 1.1.9? > > Those are the two issues I can find regarding this matter: > > https://issues.apache.org/jira/browse/CASSANDRA-4876 > https://issues.apache.org/jira/browse/CASSANDRA-5029 > > Looks like in 1.2, it defaults at 0.1, not sure about 1.1.X > > -Wei > > ----- Original Message ----- > From: "Michael Theroux" <mthero...@yahoo.com> > To: user@cassandra.apache.org > Sent: Thursday, March 7, 2013 1:18:38 PM > Subject: Bloom filters and LCS > > Hello, > > (Hopefully) Quick question. > > We are running Cassandra 1.1.9. > > I recently converted some tables from Size tiered to Leveled Compaction. The > amount of space for Bloom Filters on these tables went down tremendously > (which is expected, LCS in 1.1.9 does not use bloom filters). > > However, although its far less, its still using a number of megabytes. Why > is it not zero? > > > Column Family: XXXX > SSTable count: 526 > Space used (live): 7251063348 > Space used (total): 7251063348 > Number of Keys (estimate): 23895552 > Memtable Columns Count: 45719 > Memtable Data Size: 21207173 > Memtable Switch Count: 579 > Read Count: 21773431 > Read Latency: 4.155 ms. > Write Count: 16183367 > Write Latency: 0.029 ms. > Pending Tasks: 0 > Bloom Filter False Positives: 2442 > Bloom Filter False Ratio: 0.00245 > Bloom Filter Space Used: 44674656 > Compacted row minimum size: 73 > Compacted row maximum size: 105778 > Compacted row mean size: 1104 > > Thanks, > -Mike > > > >
