I don't remember a removing-compacted-files bug in 0.7.0, but you should absolutely upgrade to 0.7.8 for several dozen other fixes, including some severe ones -- see NEWS.txt.
On Tue, Aug 2, 2011 at 4:29 PM, Yiming Sun <yiming....@gmail.com> wrote: > Hi Jeremiah, > > Thank you for the information - it certainly is a relief. Two questions > though: > > 1. I came across an old thread which seemed to be saying 0.7.0 cassandra has > a bug and doesn't remove these compact files properly. Should we upgrade to > a newer version that has this bug fixed? > > 2. Do we must do the garbage collection via Jconsole manually? Is there > anyway I can force the GC in our code? (we are using Hector as our java > client). > > Thanks! > > > > On Tue, Aug 2, 2011 at 5:19 PM, Jeremiah Jordan > <jeremiah.jor...@morningstar.com> wrote: >> >> Connect with jconsole and run garbage collection. >> All of the files that have a -Compacted with the same name will get >> deleted the next time a full garbage collection runs, or when the node >> is restarted. They have already been combined into new files, the old >> ones just haven't been deleted yet. >> >> On Tue, 2011-08-02 at 16:09 -0400, Yiming Sun wrote: >> > Hi, >> > >> > I am new to Cassandra, and am hoping someone could help me understand >> > the (large amount of small) data files on disk that Cassandra >> > generates. >> > >> > The reason we are using Cassandra is because we are dealing with >> > thousands to millions of small text files on disk, so we are >> > experimenting with Cassandra hoping that by dropping the files >> > contents into Cassandra, it will achieve more efficient disk usage >> > because Cassandra is going to aggregate them into bigger files (one >> > file per column family, according to the wiki). >> > >> > But after we pushed a subset of the files into a single node Cassandra >> > v0.7.0 instance, we noted that in the Cassandra data directory for the >> > keyspace, there are 8.5 million very small files, most are named >> > >> > <SuperColumnFamilyName>-e-<nnnnn>.Filter.db >> > <SuperColumnFamilyName>-e-<nnnnn>.Compacted.db >> > <SuperColumnFamilyName>-e-<nnnnn>.Index.db >> > <SuperColumnFamilyName>-e-<nnnnn>.Statistics.db >> > >> > and among these files, the Compacted.db are always empty, Filter and >> > Index are under 100 bytes, and Statistics are around 4k. >> > >> > What are these files? Why are there so many of them? We originally >> > hope that Cassandra was going to solve our issue with the small files >> > we have, but now it doesn't seem to help -- we still end up with tons >> > of small files. Is there any way to reduce/combine these small >> > files? >> > >> > Thanks. >> > >> > -- Y. >> > > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
