Qingqing Zhou wrote: > I am not sure if this idea was mentioned before. > > The basic prefix btree idea is quite straightforward, i.e., try to > compress the key items within a data page by sharing the common prefix. > Thus the fanout of the page is increased and the benefits is obvious > theorectically. > <snip> > > So together, there are basically four types of possible sharing: > column-wise (case 1), character-wise (case 2), column-character-wise (case > 3), and byte-wise (case 4). > Oracle implements something similar called index compression, but I believe it is only for common column values. I haven't checked in versions>9r1 so maybe there are other options implemented by now.
Jonathan Lewis describes some pros and cons here: http://www.jlcomp.demon.co.uk/faq/compress_ind.html -- _______________________________ This e-mail may be privileged and/or confidential, and the sender does not waive any related rights and obligations. Any distribution, use or copying of this e-mail or the information it contains by other than an intended recipient is unauthorized. If you received this e-mail in error, please advise me (by return e-mail or otherwise) immediately. _______________________________ ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
