Hi! I ran UPDATE COLUMN FAMILY cf_name WITH compression_options={sstable_compression:SnappyCompressor, chunk_length_kb:64};
I then ran on all my nodes (3) sudo nodetool -h localhost scrub tok cf_name I have replication factor 3. The size of the data on disk was cut in half in the first node and in the jmx I can see that indeed the compression ration is 0.46. But on nodes 2 and 3 nothing happened. In the jmx I can see that compression ratio is 0 and the size of the files of disk stayed the same. In cli ColumnFamily: cf_name Key Validation Class: org.apache.cassandra.db.marshal.UUIDType Default column value validator: org.apache.cassandra.db.marshal.UTF8Type Columns sorted by: org.apache.cassandra.db.marshal.CompositeType(org.apache.cassandra.db.marshal.UTF8Type,org.apache.cassandra.db.marshal.UTF8Type) Row cache size / save period in seconds / keys to save : 0.0/0/all Row Cache Provider: org.apache.cassandra.cache.SerializingCacheProvider Key cache size / save period in seconds: 200000.0/14400 GC grace seconds: 864000 Compaction min/max thresholds: 4/32 Read repair chance: 1.0 Replicate on write: true Bloom Filter FP chance: default Built indexes: [] Compaction Strategy: org.apache.cassandra.db.compaction.SizeTieredCompactionStrategy Compression Options: chunk_length_kb: 64 sstable_compression: org.apache.cassandra.io.compress.SnappyCompressor Can anyone help? Thanks *Tamar Fraenkel * Senior Software Engineer, TOK Media [image: Inline image 1] ta...@tok-media.com Tel: +972 2 6409736 Mob: +972 54 8356490 Fax: +972 2 5612956 On Mon, Sep 24, 2012 at 8:37 AM, Tamar Fraenkel <ta...@tok-media.com> wrote: > Thanks all, that helps. Will start with one - two CFs and let you know the > effect > > > *Tamar Fraenkel * > Senior Software Engineer, TOK Media > > [image: Inline image 1] > > ta...@tok-media.com > Tel: +972 2 6409736 > Mob: +972 54 8356490 > Fax: +972 2 5612956 > > > > > > On Sun, Sep 23, 2012 at 8:21 PM, Hiller, Dean <dean.hil...@nrel.gov>wrote: > >> As well as your unlimited column names may all have the same prefix, >> right? Like "accounts".rowkey56, "accounts".rowkey78, etc. etc. so the >> "accounts gets a ton of compression then. >> >> Later, >> Dean >> >> From: Tyler Hobbs <ty...@datastax.com<mailto:ty...@datastax.com>> >> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" < >> user@cassandra.apache.org<mailto:user@cassandra.apache.org>> >> Date: Sunday, September 23, 2012 11:46 AM >> To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" < >> user@cassandra.apache.org<mailto:user@cassandra.apache.org>> >> Subject: Re: compression >> >> column metadata, you're still likely to get a reasonable amount of >> compression. This is especially true if there is some amount of repetition >> in the column names, values, or TTLs in wide rows. Compression will almost >> always be beneficial unless you're already somehow CPU bound or are using >> large column values that are high in entropy, such as pre-compressed or >> encrypted data. >> > >
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