I, too, can never remember the exact formula, so I always have to look it up in Lucene in Action. If you have LIA, look at the "Tuning indexing performance" section (2.7.1, page 42): http://www.lucenebook.com/search?query=segment+merge+files
Otis ----- Original Message ---- From: Erik Hatcher <[EMAIL PROTECTED]> To: java-user@lucene.apache.org Sent: Monday, April 24, 2006 4:38:48 AM Subject: Re: Segments creation To be honest, I have to look up what has been written on this topic to get the answer right myself. Otis did a thorough write-up in "Lucene in Action". Lucene's javadocs also cover these factors here: <http://lucene.apache.org/java/docs/api/org/apache/lucene/index/ IndexWriter.html> look at the setters, particularly setMaxMergeDocs. Erik On Apr 23, 2006, at 9:47 PM, John Paige wrote: > Thanks for the responses. For fault tolerance, we have decided to > set the > "mergeFactor" to 1, ie, we want to update the on-disk index every > time a > document is added via addDocument(). My question was that will this > create a > new segment every time? Or is there a separate "segmentFactor", > such that an > incremental index update updates an existing segment *on disk*, only > starting a new segment once a given number of documents have been > added to > the index? > > Thanks, > John > > On 4/23/06, Erik Hatcher <[EMAIL PROTECTED]> wrote: >> >> If you use the compound format, all "files" are kept inside a single >> filesystem file. >> >> Erik >> >> >> On Apr 23, 2006, at 2:13 PM, John Paige wrote: >> >>> So, if I use one indexwriter instance to index one document, will >>> it create >>> a segment per document? >>> How many files per segment get added if I use compound index file >>> format? >>> >>> Thanks, >>> John >>> >>> On 4/23/06, Erik Hatcher <[EMAIL PROTECTED]> wrote: >>>> >>>> If you use the compound index file format (the default since Lucene >>>> 1.4) you'll avoid the file descriptors issue. If you add 10 >>>> documents at one time with a single IndexWriter, you will not >>>> create >>>> 10 segments, only one segment (generally speaking, based on the >>>> default segment factors). >>>> >>>> Erik >>>> >>>> >>>> On Apr 23, 2006, at 9:48 AM, John Paige wrote: >>>> >>>>> Hello all, >>>>> In my application it is required to build an index for each >>>>> user. We need >>>>> to add documents to the existing index frequently. >>>>> We cannot use RAMDirectory to create a RAM index and merge it >>>>> with the >>>>> FSDirectory index later on based on the mergefactor. We need to >>>>> add >>>>> each >>>>> document in the FSDirectory based index. >>>>> We are afraid of getting into the "out of file descriptors" >>>>> issue , >>>>> so my >>>>> question is, does lucene create a segment for each document that >>>>> gets added >>>>> to the FS based index i.e. will adding 10 documents to the >>>>> existing >>>>> index >>>>> create 10 segments? >>>>> >>>>> Thanks, >>>>> John >>>> >>>> >>>> ------------------------------------------------------------------- >>>> -- >>>> To unsubscribe, e-mail: [EMAIL PROTECTED] >>>> For additional commands, e-mail: [EMAIL PROTECTED] >>>> >>>> >> >> >> --------------------------------------------------------------------- >> To unsubscribe, e-mail: [EMAIL PROTECTED] >> For additional commands, e-mail: [EMAIL PROTECTED] >> >> --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]