> BTW, Joshua, could you please let me know or give me any pointers for > the reason why fsync=off option exists on PostgreSQL although PostgreSQL
A couple of reasons that I can think of. One would be data loads or restoring from backup. Another would be on data that you can afford to throw away. > developers does not allow sacrificing data integrity ? > If the reason is famous and clear in the community, I am sorry for > bothering you. No bother at all! We invite all good ideas and I am glad to see more from our eastern community participate. Another option you might want to look at to further give yourself a boost in performance is full_page_writes. Joshua D. Drake > > > -- Hideyuki > > Joshua D. Drake wrote: >> Hideyuki Kawashima wrote: >> >>> Hello PostgreSQL Hackers, >>> >>> I have made a modification of PostgreSQL which accelerates INSERT/UPDATE >>> using UPS. The name of the software is "Sigres", and the philosophy is >>> considering a battery supplied memory as a persistent device instead of a >>> disk. You can download Sigres from http://sourceforge.jp/projects/sigres/ . >>> >>> In the maximum case, Sigres is 7 times faster than PostgreSQL default >>> (fsync=on) in my environment (CoreDuo 2.66GHz, UDMA/133), and it is also >>> 10% faster than PostgreSQL without fsync (fsync=off). >>> >> Interesting and what happens when the UPS fails? My main concern is that >> one of the purposes of PostgreSQL is data integrity. I am all for every >> performance enhancement we can achieve, that does *not* sacrifice that. >> >> Sincerely, >> >> Joshua D. Drake >> >> >>> The magic lies in usually skipping XLogWrite() and ignoring WALWriteLock. >>> The exceptions are XLogWrite() calls from AdvanceXLInsertBuffer(). In >>> addition, in XLogFileClose() issue_xlog_fsync() before close(). (In this >>> point, Sigres is different from just simply setting fsync=off.) >>> >>> Although I think Sigres can be considered as one of the future directions >>> of PostgreSQL, I do not know whether this software can be accepted or not. >>> Could you please give me some comments ? >>> >>> Best Regards, >>> >>> -- Hideyuki Kawashima >>> Assistant Professor, University of Tsukuba >>> >>> >>> >>> ---------------------------(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 >>> >>> >> >> > > > ---------------------------(end of broadcast)--------------------------- > TIP 6: explain analyze is your friend > -- === The PostgreSQL Company: Command Prompt, Inc. === Sales/Support: +1.503.667.4564 || 24x7/Emergency: +1.800.492.2240 Providing the most comprehensive PostgreSQL solutions since 1997 http://www.commandprompt.com/ Donate to the PostgreSQL Project: http://www.postgresql.org/about/donate PostgreSQL Replication: http://www.commandprompt.com/products/ ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
