hmmm... when i run statspack during a big load. most of my waits are from redo log waits and read from a staging datafile. we have all of our datafiles on the same I/O mount. We are using a Network Appliance back end with asynch I/O.
are you telling me that putting these files on seperate mount points will have no effect? I dont quite follow asynch I/O. I dont have much of a hard ware OS background. I cant find any docs or articles on how to tune Parallel Operations. All I see are basic syntax. Do you know of any? ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Thursday, September 18, 2003 5:24 PM > If you want rules of thumb, then take CPU_COUNT+1 up to CPU_COUNT *2. > > I think LIO & PIO ratio is irrelevant, the most important is whether you are > able to construct optimal parallel execution plan, e.g. avoid excessive > parallel slave messaging & waiting. This is mostly design and SQL issue. > > The number mount points is irrelevant novadays as well IMHO, especially when > you're using async IO, SANs & SAME like architecture. The only thing what > comes into my mind where splitting into mount points (thus different file > systems) helps performance wise, is that with more file systems you got more > file system locks and you can spread contention for these locks that way. > > Tanel. > > ----- Original Message ----- > To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> > Sent: Thursday, September 18, 2003 9:34 PM > > > > i know there are no magic formulas, but im hoping for something better > than trial and error. i would assume that parallel query helps most when: > > > > 1. are doing work off of multiple mount points. > > 2. Have alot more LIOs to perform than PIOs(such as sorts). > > > > am i close on this? > > > > > > From: "M Rafiq" <[EMAIL PROTECTED]> > > > Date: 2003/09/18 Thu PM 01:34:44 EDT > > > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > > > Subject: Re: max parallel query > > > > > > Tanel, > > > You are right. There is a param parallel_automatic(I don't remember > exact > > > name as I don't have access to database) which should be set to true and > let > > > system decide how many pq slave to be used. For max_parallel_server > default > > > is 5 and can be set to higher number which memory and cpu can handle. > It > > > is faster because it uses all system resources at a given time. > > > > > > Rarallel process can be used for large batch jobs during off-peak time. > > > > > > Regards > > > Rafiq > > > > > > > > > Reply-To: [EMAIL PROTECTED] > > > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > > > Date: Thu, 18 Sep 2003 08:39:44 -0800 > > > > > > There is no simple magic formula how many parallel slaves you should > have. > > > It all depends on your CPU and IO utilization. Yes, utilization, because > if > > > your CPUs or IO are running at their limits already, you won't benefit > from > > > parallel execution at all. In fact PX may make the situation even worse, > > > because it's designed to give you the results the fastest way, not the > most > > > efficient way. > > > > > > Tanel. > > > > > > ----- Original Message ----- > > > To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> > > > Sent: Thursday, September 18, 2003 6:15 PM > > > > > > > > > > We run multiple instances on the same server. My understanding is > > > max_parallel_servers should be set to 4 x CPU. We have 4 CPUs which > means > > > 16. > > > > > > > > however, does this take into account multiple instances on the same > > > server? > > > > > > > > > > > > -- > > > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > > > -- > > > > Author: <[EMAIL PROTECTED] > > > > INET: [EMAIL PROTECTED] > > > > > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > > > San Diego, California -- Mailing list and web hosting services > > > > --------------------------------------------------------------------- > > > > To REMOVE yourself from this mailing list, send an E-Mail message > > > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > > > > the message BODY, include a line containing: UNSUB ORACLE-L > > > > (or the name of mailing list you want to be removed from). You may > > > > also send the HELP command for other information (like subscribing). > > > > > > > > > > > > > -- > > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > > -- > > > Author: Tanel Poder > > > INET: [EMAIL PROTECTED] > > > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > > San Diego, California -- Mailing list and web hosting services > > > --------------------------------------------------------------------- > > > To REMOVE yourself from this mailing list, send an E-Mail message > > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > > > the message BODY, include a line containing: UNSUB ORACLE-L > > > (or the name of mailing list you want to be removed from). You may > > > also send the HELP command for other information (like subscribing). > > > > > > _________________________________________________________________ > > > Send and receive larger attachments with Hotmail Extra Storage. > > > http://join.msn.com/?PAGE=features/es > > > > > > -- > > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > > -- > > > Author: M Rafiq > > > INET: [EMAIL PROTECTED] > > > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > > San Diego, California -- Mailing list and web hosting services > > > --------------------------------------------------------------------- > > > To REMOVE yourself from this mailing list, send an E-Mail message > > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > > > the message BODY, include a line containing: UNSUB ORACLE-L > > > (or the name of mailing list you want to be removed from). You may > > > also send the HELP command for other information (like subscribing). > > > > > > > -- > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > -- > > Author: <[EMAIL PROTECTED] > > INET: [EMAIL PROTECTED] > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > San Diego, California -- Mailing list and web hosting services > > --------------------------------------------------------------------- > > To REMOVE yourself from this mailing list, send an E-Mail message > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > > the message BODY, include a line containing: UNSUB ORACLE-L > > (or the name of mailing list you want to be removed from). You may > > also send the HELP command for other information (like subscribing). > > > > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Tanel Poder > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB ORACLE-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Ryan INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
