From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Yura Umanets" Subject: Re: using reiserfs as a DB Date: Mon, 22 Apr 2002 21:12:36 +0300 Message-ID: <3CC45294.2060806@priocom.com> References: <20020421205328.GA8407@vega.ipal.net> <20020422172009.A1109@namesys.com> <20020422174449.GC8407@vega.ipal.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: list-help: list-unsubscribe: list-post: List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Phil Howard Cc: reiserfs-list@namesys.com Phil Howard wrote: > "By the keys" means what? Are the keys the filenames/paths, The key in reiserfs seems like four-dimentional coordinate of the certain item in filesystem. The first component is identifier of directory where given object (file or directory) lies. Second - identifier of the given object. Third component - offset inside object. If object is file, then offset is offset inside this file, if directory - hashed name of first entry in this direntry. And finally last component is type of the item (statdata, direntry, direct item, indirect item). Therefore it is very fast to access corresponding object item. This is just $tree_height blocks to be read. > Does the raw interface simply shortcut access to files in a normal reiserfs > mounted filesystem, which can also still be accessed the usual way, or is it > a special object which can only be accessed that way (if so, then it loses > the advantage of being able to use conventional tools that work on files, and > ends up being pretty much a DB lib implemented in kernel space). Since most > operations would be open() file, read() file once (because nothing would be > larger than one block), and close(), a single system call that allowed to > just fetch the contents given a name would certainly be a plus for the server > component. The instance of what is a raw access to files and directories you can see on http://reiserfs.linux.kiev.ua/progsreiserfs-0.3.0.tar.gz in files: object.c, file.c, dir.c