Thanks jonathan, clear! On Wed, May 12, 2010 at 12:22 AM, Jonathan Ellis <jbel...@gmail.com> wrote:
> from http://wiki.apache.org/cassandra/ArchitectureInternals: > > Making this concurrency-safe without blocking writes or reads while we > remove the old SSTables from the list and add the new one is tricky, > because naive approaches require waiting for all readers of the old > sstables to finish before deleting them (since we can't know if they > have actually started opening the file yet; if they have not and we > delete the file first, they will error out). The approach we have > settled on is to not actually delete old SSTables synchronously; > instead we register a phantom reference with the garbage collector, so > when no references to the SSTable exist it will be deleted. (We also > write a compaction marker to the file system so if the server is > restarted before that happens, we clean out the old SSTables at > startup time.) > > On Tue, May 11, 2010 at 10:50 AM, Schubert Zhang <zson...@gmail.com> > wrote: > > In current 0.6.1, after a long time of compation, the old SSTable files > are > > still there, with the mark of > > "CFName-id-Compacted" zero sized file. > > > > Whey not delete them immediately? What is the policy in 0.6.1? > > > > See following examples. > > > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-1263-Compacted > > -rw-rw-r-- 1 cassandra cassandra 3643422558 May 11 12:21 > LZO-1263-Data.db > > -rw-rw-r-- 1 cassandra cassandra 939685 May 11 12:21 > LZO-1263-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 12:21 > LZO-1263-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-1597-Compacted > > -rw-rw-r-- 1 cassandra cassandra 2365082186 May 11 14:49 > LZO-1597-Data.db > > -rw-rw-r-- 1 cassandra cassandra 751765 May 11 14:49 > LZO-1597-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 14:49 > LZO-1597-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-1614-Compacted > > -rw-rw-r-- 1 cassandra cassandra 31064427729 May 11 16:42 > LZO-1614-Data.db > > -rw-rw-r-- 1 cassandra cassandra 751765 May 11 16:42 > LZO-1614-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 16:42 > LZO-1614-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-1879-Compacted > > -rw-rw-r-- 1 cassandra cassandra 3536115771 May 11 17:29 > LZO-1879-Data.db > > -rw-rw-r-- 1 cassandra cassandra 751765 May 11 17:29 > LZO-1879-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 17:29 > LZO-1879-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-2049-Compacted > > -rw-rw-r-- 1 cassandra cassandra 7910248440 May 11 19:17 > LZO-2049-Data.db > > -rw-rw-r-- 1 cassandra cassandra 1691365 May 11 19:17 > LZO-2049-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 19:17 > LZO-2049-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-2169-Compacted > > -rw-rw-r-- 1 cassandra cassandra 417646680 May 11 19:56 > LZO-2169-Data.db > > -rw-rw-r-- 1 cassandra cassandra 2500645 May 11 19:56 > LZO-2169-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 19:56 > LZO-2169-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-2184-Compacted > > -rw-rw-r-- 1 cassandra cassandra 3485810361 May 11 20:08 > LZO-2184-Data.db > > -rw-rw-r-- 1 cassandra cassandra 751765 May 11 20:08 > LZO-2184-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 20:08 > LZO-2184-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-2188-Compacted > > -rw-rw-r-- 1 cassandra cassandra 663325064 May 11 20:10 > LZO-2188-Data.db > > -rw-rw-r-- 1 cassandra cassandra 751765 May 11 20:10 > LZO-2188-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 20:10 > LZO-2188-Index.db > > -rw-rw-r-- 1 cassandra cassandra 0 May 11 23:35 > LZO-2189-Compacted > > -rw-rw-r-- 1 cassandra cassandra 29651624 May 11 20:09 > LZO-2189-Data.db > > -rw-rw-r-- 1 cassandra cassandra 114789 May 11 20:09 > LZO-2189-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 3691960 May 11 20:09 > LZO-2189-Index.db > > -rw-rw-r-- 1 cassandra cassandra 52910891687 May 11 23:35 > LZO-2190-Data.db > > -rw-rw-r-- 1 cassandra cassandra 1618405 May 11 23:35 > LZO-2190-Filter.db > > -rw-rw-r-- 1 cassandra cassandra 6034764 May 11 23:35 > LZO-2190-Index.db > > > > > > -- > Jonathan Ellis > Project Chair, Apache Cassandra > co-founder of Riptano, the source for professional Cassandra support > http://riptano.com >
