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From Venkatesh Arivazhagan <venkey.a...@gmail.com>
Subject Re: Help with tombstones and compaction
Date Mon, 21 Sep 2015 20:41:41 GMT
Thank you for your reply Jeff!

I will switch to Cassandra 2.1.9.

Quick follow up question: Does the schema, settings I have setup look
alright? My timestamp column's type is blob - I was wondering if this could
confuse DTCS?

On Sun, Sep 20, 2015 at 3:37 PM, Jeff Jirsa <jeff.jirsa@crowdstrike.com>
wrote:

> 2.1.4 is getting pretty old. There’s a DTCS deletion tweak in 2.1.5 (
> https://issues.apache.org/jira/browse/CASSANDRA-8359 ) that may help you.
>
> 2.1.5 and 2.1.6 have some memory leak issues in DTCS, so go to 2.1.7 or
> newer (probably 2.1.9 unless you have a compelling reason not to go to
> 2.1.9)
>
>
> From: Venkatesh Arivazhagan
> Reply-To: "user@cassandra.apache.org"
> Date: Sunday, September 20, 2015 at 2:48 PM
> To: "user@cassandra.apache.org"
> Subject: Help with tombstones and compaction
>
> Hi Guys,
>
> I have a Cassandra 2.1.4 cluster with 14 nodes. I am using it primarily
> for storing time series data collected via KairosDB.
> The default TTL for data inserted into the column family named data_points
> is 12hrs. I have also set the gc_grace_seconds to 12 hrs.
> In-spite of this my disk space keeps on increasing and it looks like
> tombstones are never dropped.
>
> It looks like compactions are happening on a regular basis. The SSTable
> count does not seem outrageous either. It is constantly between ~10 to ~22.
>
> Am I doing anything wrong? Is there a way to mitigate this?
>
> Attached:
> * DESC output for my keyspace
> * Disk usage graph
> * LiveSSTable Count graph
>
>
> --------------------------------------------------------------------------------------------------------------------------
>
> CREATE KEYSPACE kairosdb WITH replication = {'class': 'SimpleStrategy',
> 'replication_factor': '3'}  AND durable_writes = true;
>
> CREATE TABLE kairosdb.data_points (
>     key blob,
>     column1 blob,
>     value blob,
>     PRIMARY KEY (key, column1)
> ) WITH COMPACT STORAGE
>     AND CLUSTERING ORDER BY (column1 ASC)
>     AND bloom_filter_fp_chance = 0.01
>     AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
>     AND comment = ''
>     AND compaction = {'max_sstable_age_days': '365', 'base_time_seconds':
> '3600', 'max_threshold': '32', 'timestamp_resolution': 'MILLISECONDS',
> 'enabled': 'true', 'tombstone_compaction_interval': '1', 'min_threshold':
> '4', 'tombstone_threshold': '.1', 'class':
> 'org.apache.cassandra.db.compaction.DateTieredCompactionStrategy'}
>     AND compression = {'sstable_compression':
> 'org.apache.cassandra.io.compress.LZ4Compressor'}
>     AND dclocal_read_repair_chance = 0.1
>     AND default_time_to_live = 43200
>     AND gc_grace_seconds = 43200
>     AND max_index_interval = 2048
>     AND memtable_flush_period_in_ms = 0
>     AND min_index_interval = 128
>     AND read_repair_chance = 0.1
>     AND speculative_retry = 'NONE';
>
> CREATE TABLE kairosdb.row_key_index (
>     key blob,
>     column1 blob,
>     value blob,
>     PRIMARY KEY (key, column1)
> ) WITH COMPACT STORAGE
>     AND CLUSTERING ORDER BY (column1 ASC)
>     AND bloom_filter_fp_chance = 0.01
>     AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
>     AND comment = ''
>     AND compaction = {'min_threshold': '4', 'class':
> 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
> 'max_threshold': '32'}
>     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 = 43200
>     AND max_index_interval = 2048
>     AND memtable_flush_period_in_ms = 0
>     AND min_index_interval = 128
>     AND read_repair_chance = 0.1
>     AND speculative_retry = 'NONE';
>
> CREATE TABLE kairosdb.string_index (
>     key blob,
>     column1 text,
>     value blob,
>     PRIMARY KEY (key, column1)
> ) WITH COMPACT STORAGE
>     AND CLUSTERING ORDER BY (column1 ASC)
>     AND bloom_filter_fp_chance = 0.01
>     AND caching = '{"keys":"ALL", "rows_per_partition":"NONE"}'
>     AND comment = ''
>     AND compaction = {'min_threshold': '4', 'class':
> 'org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy',
> 'max_threshold': '32'}
>     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 = 43200
>     AND max_index_interval = 2048
>     AND memtable_flush_period_in_ms = 0
>     AND min_index_interval = 128
>     AND read_repair_chance = 0.1
>     AND speculative_retry = 'NONE';
>
> --------------------------------------------------------------------------------------------------------------------------
>

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