Hi, In Lucene there are two types of index structure compound index and multi-file index. In multi-file index, when new documents are inserted to an index, they are stored in a separate segment; this causes increase of files in an index structure. Therefore, multi-file index has more files than compound index. Compound index type consists of three files; two of them are "deletable" file that shows the unused files in index and "segments" file that shows the segment names and their size. The third one contains the all indexed documents and their field values. In compound index all indexed files are merged into one single file. So, the number of files in the index is minimized. The advantage of multi-file is the time for indexing documents takes less than compound file. Because, in compound file the indexed files are in addition merged into one single file. This can be suitable when the number of documents is large while indexing. On the other hand, the advantage of compound file appears in searching. Because, the total number of file accesses for reading data are minimum in compound index. In contrast, using multi-file index the file fetches increase because the program needs to open more files in order to retrieve required documents from the index. This is important while search time in an application is in consideration.
I do prefer to use compoundFile(true) as I work on unix platforms otherwise you will end up with "too many open files" very often! best regards Simon btw: nice to see another person from Berlin on the list! ----------- mailto: [EMAIL PROTECTED] On 10/10/06, Supriya Kumar Shyamal <[EMAIL PROTECTED]> wrote:
Hello All, I have question regarding the use of Compound file fo rindex, what is the advantage & disadvantage of enabling use of compound file(which is default I think) or disabling the useo of it. Thanks, supriya -- Mit freundlichen Grüßen / Regards Supriya Kumar Shyamal Software Developer tel +49 (30) 443 50 99 -22 fax +49 (30) 443 50 99 -99 email [EMAIL PROTECTED] ___________________________ artnology GmbH Milastr. 4 10437 Berlin ___________________________ http://www.artnology.com __________________________________________________________________________ News / Aktuelle Projekte: * artnology gewinnt Ausschreibung des Bundesministeriums des Innern: Softwarelösung für die Verwaltung der Sammlung zeitgenössischer Kunstwerke zur kulturellen Repräsentation des Bundes. Projektreferenzen: * Globaler eShop und Corporate-Site für Springer: www.springeronline.com * E-Detailing-Portal für Novartis: www.interaktiv.novartis.de * Service-Center-Plattform für Biogen: www.ms-life.de * eCRM-System für Grünenthal: www.gruenenthal.com ___________________________________________________________________________ --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
