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https://issues.apache.org/jira/browse/CASSANDRA-6654?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13913213#comment-13913213
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Russ Hatch commented on CASSANDRA-6654:
---------------------------------------
[~jbellis] I have been able to reproduce the issue on 1.2.13 using the schema
provided by Keith.
For the test I created a 3 node cluster at amazon (RF=2) and created data using
scaled down values for the gc grace and TTL's provided by Keith in the comment
above this one. The test itself does no data removal but counts on TTL expiry
to do that. Currently all 3 nodes are reporting a DroppableTombstoneRatio of
about 40%. I ran nodetool compact on a single node and there was not a
noticeable drop. I will attach my data creation script (basically just a dumb
loop that creates data with various TTL's) and I've still got my cluster
running on ec2 for the time being.
> Droppable tombstones are not being removed from LCS table despite being above
> 20%
> ---------------------------------------------------------------------------------
>
> Key: CASSANDRA-6654
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6654
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: 1.2.13 VNodes with murmur3
> Reporter: Keith Wright
> Assignee: Russ Hatch
> Attachments: Screen Shot 2014-02-05 at 9.38.20 AM.png
>
>
> JMX is showing that one of our CQL3 LCS tables has a droppable tombstone
> ratio above 20% and increasing (currently at 28%). Compactions are not
> falling behind and we are using the OOTB setting for this feature so I would
> expect not to go above 20% (will attach screen shot from JMX). Table
> description:
> CREATE TABLE global_user (
> user_id timeuuid,
> app_id int,
> type text,
> name text,
> extra_param map<text, text>,
> last timestamp,
> paid boolean,
> sku_time map<text, timestamp>,
> values map<timestamp, float>,
> PRIMARY KEY (user_id, app_id, type, name)
> ) WITH
> bloom_filter_fp_chance=0.100000 AND
> caching='KEYS_ONLY' AND
> comment='' AND
> dclocal_read_repair_chance=0.000000 AND
> gc_grace_seconds=86400 AND
> read_repair_chance=0.100000 AND
> replicate_on_write='true' AND
> populate_io_cache_on_flush='false' AND
> compaction={'sstable_size_in_mb': '160', 'class':
> 'LeveledCompactionStrategy'} AND
> compression={'chunk_length_kb': '8', 'crc_check_chance': '0.1',
> 'sstable_compression': 'LZ4Compressor'};
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