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From Nate McCall <n...@thelastpickle.com>
Subject Re: Significant drop in storage load after 2.1.6->2.1.8 upgrade
Date Sat, 18 Jul 2015 19:40:27 GMT
Perhaps https://issues.apache.org/jira/browse/CASSANDRA-9592 got
compactions moving forward for you? This would explain the drop.

However, the discussion on
https://issues.apache.org/jira/browse/CASSANDRA-9683 seems to be similar to
what you saw and that is currently being investigated.

On Fri, Jul 17, 2015 at 10:24 AM, Mike Heffner <mike@librato.com> wrote:

> Hi all,
>
> I've been upgrading several of our rings from 2.1.6 to 2.1.8 and I've
> noticed that after the upgrade our storage load drops significantly (I've
> seen up to an 80% drop).
>
> I believe most of the data that is dropped is tombstoned (via TTL
> expiration) and I haven't detected any data loss yet. However, can someone
> point me to what changed between 2.1.6 and 2.1.8 that would lead to such a
> significant drop in tombstoned data? Looking at the changelog there's
> nothing that jumps out at me. This is a CF definition from one of the CFs
> that had a significant drop:
>
> > describe measures_mid_1;
>
> CREATE TABLE "Metrics".measures_mid_1 (
>     key blob,
>     c1 int,
>     c2 blob,
>     c3 blob,
>     PRIMARY KEY (key, c1, c2)
> ) WITH COMPACT STORAGE
>     AND CLUSTERING ORDER BY (c1 ASC, c2 ASC)
>     AND bloom_filter_fp_chance = 0.01
>     AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
>     AND comment = ''
>     AND compaction = {'class':
> 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy'}
>     AND compression = {'sstable_compression':
> 'org.apache.cassandra.io.compress.LZ4Compressor'}
>     AND dclocal_read_repair_chance = 0.1
>     AND default_time_to_live = 0
>     AND gc_grace_seconds = 0
>     AND max_index_interval = 2048
>     AND memtable_flush_period_in_ms = 0
>     AND min_index_interval = 128
>     AND read_repair_chance = 0.0
>     AND speculative_retry = '99.0PERCENTILE';
>
> Thanks,
>
> Mike
>
> --
>
>   Mike Heffner <mike@librato.com>
>   Librato, Inc.
>
>


-- 
-----------------
Nate McCall
Austin, TX
@zznate

Co-Founder & Sr. Technical Consultant
Apache Cassandra Consulting
http://www.thelastpickle.com

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