Hi, this is very strange. in my experience .cfs files are written once and never modified. this write-once pattern is actually used for almost all files, except the segments.gen file you mentioned. E.g. see [0] by Mike McCandless when he talks about LUCENE-5574.
is it possible the entire lucene index is replaced by oak? regards marcel [0] http://blog.mikemccandless.com/2014/04/testing-lucenes-index-durability-aft er.html On 20/10/14 11:59, "Chetan Mehrotra" <[email protected]> wrote: >While working on copy on read directory support (OAK-1724) and was >checking how Lucene manages the index files. Following observation can >be made with various test runs > >A - Small Index use Compound File format >------------------ > >If index contain few entries then it seems it uses the compound file >format as directory listing shows only following files (filename - >size) > >_0.cfs - 621 >_0.cfe - 194 >segments.gen - 20 >segments_1 - 81 >_0.si - 266 > >If the index gets updates the _0.cfs file size changes and other remains >same > >B - Large index store index file seprately >-------------------- > >For large index (not sure of threshold) Lucene seems to store the >various index file separately and there probably the file do not get >modified and only new file get created > >Question >------------- >1. Is this switch from cfs format to storing in separate files is >automatic and done by Lucene after index reaches certain size. Or this >done something specifically in Oak? >2. Lucene would not modify existing file in a directory unless > a. In compound storage cfs file would get modified. There also >modification would be append only? > b. segment.gen - This would get modified everytime > c. If separate files are used then any file would never be modified >and only new files would be created > >Chetan Mehrotra >PS: Probably the question is more appropriate for Lucene DL but >checking here first to see if something in Oak is different from >default
