incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Edward Capriolo <edlinuxg...@gmail.com>
Subject Re: Bloom filters and LCS
Date Thu, 07 Mar 2013 21:26:55 GMT
It was found out that that having no bloom filter is a bad idea because it
causes issues where deleted rows are never removed from disk. Newer
versions have fixed this. You should adjust your bloom filter settings to
be >0 sized.

On Thu, Mar 7, 2013 at 4:18 PM, Michael Theroux <mtheroux2@yahoo.com> wrote:

> 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
>
>
>

Mime
View raw message