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From Jeff Jirsa <>
Subject Re: Re : Purging tombstones from a particular row in SSTable
Date Wed, 27 Jul 2016 21:51:05 GMT
220kb worth of tombstones doesn’t seem like enough to worry about.



From: sai krishnam raju potturi <>
Reply-To: "" <>
Date: Wednesday, July 27, 2016 at 2:43 PM
To: Cassandra Users <>
Subject: Re: Re : Purging tombstones from a particular row in SSTable


and also the sstable size in question is like 220 kb in size. 





On Wed, Jul 27, 2016 at 5:41 PM, sai krishnam raju potturi <> wrote:

it's set to 1800 Vinay. 


 bloom_filter_fp_chance=0.010000 AND

  caching='KEYS_ONLY' AND

  comment='' AND

  dclocal_read_repair_chance=0.100000 AND

  gc_grace_seconds=1800 AND

  index_interval=128 AND

  read_repair_chance=0.000000 AND

  replicate_on_write='true' AND

  populate_io_cache_on_flush='false' AND

  default_time_to_live=0 AND

  speculative_retry='99.0PERCENTILE' AND

  memtable_flush_period_in_ms=0 AND

  compaction={'min_sstable_size': '1024', 'tombstone_threshold': '0.01', 'tombstone_compaction_interval':
'1800', 'class': 'SizeTieredCompactionStrategy'} AND

  compression={'sstable_compression': 'LZ4Compressor'};





On Wed, Jul 27, 2016 at 5:34 PM, Vinay Kumar Chella <> wrote:

What is your GC_grace_seconds set to?


On Wed, Jul 27, 2016 at 1:13 PM, sai krishnam raju potturi <> wrote:

thanks Vinay and DuyHai. 


    we are using verison 2.0.14. I did "user defined compaction" following the instructions
in the below link, The tombstones still persist even after that.


Also, we changed the tombstone_compaction_interval : 1800 and tombstone_threshold : 0.1, but
it did not help.






On Wed, Jul 27, 2016 at 4:05 PM, DuyHai Doan <> wrote:

This feature is also exposed directly in nodetool from version Cassandra 3.4 


nodetool compact --user-defined <SSTable file>


On Wed, Jul 27, 2016 at 9:58 PM, Vinay Chella <> wrote:

You can run file level compaction using JMX to get rid of tombstones in one SSTable. Ensure
you set GC_Grace_seconds such that 


current time >= deletion(tombstone time)+ GC_Grace_seconds 


File level compaction

/usr/bin/java -jar cmdline-jmxclient-0.10.3.jar - localhost:
 org.apache.cassandra.db:type=CompactionManager forceUserDefinedCompaction="'${KEYSPACE}','${



On Wed, Jul 27, 2016 at 11:59 AM, sai krishnam raju potturi <> wrote:


  we have a columnfamily that has around 1000 rows, with one row is really huge (million columns).
95% of the row contains tombstones. Since there exists just one SSTable , there is going to
be no compaction kicked in. Any way we can get rid of the tombstones in that row?


Userdefined compaction nor nodetool compact had no effect. Any ideas folks?











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