Linux has two patches to deal with that. One is the "highpte" patch which allows page table entries in "high memory" (i.e. after 1Gb). The other is "bigpages" which allows larger pages (i.e. 4mb instead of 4kb), thus fewer page table entries. Both patches are for Red Hat AS 2.1. I imagine that the proprietary UNIXes dealt with this a *long* time ago. Oracle and other long-time UNIX ISVs are pretty much having to lead the Linux vendors by the hand on such things...
----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Tuesday, March 04, 2003 10:19 AM > > A late-breaking thought - but it's not my area > of expertise, so others may laugh. > > If you have a very large SGA, don't you end > up with a very large 'page table' at the O/S > level to map virtual memory to real memory. > And if you do, doesn't this affect the speed > and cost of a context switch. If so, you may > waste a lot of resources task-switching rather > than working - especially if you system is > designed to do a very large number of very > small queries. > > Any comments from Unix hot-shots ? > > Regards > > Jonathan Lewis > http://www.jlcomp.demon.co.uk > > Coming soon one-day tutorials: > Cost Based Optimisation > Trouble-shooting and Tuning > Indexing Strategies > (see http://www.jlcomp.demon.co.uk/tutorial.html ) > > ____UK_______March 19th > ____UK_______April 8th > ____UK_______April 22nd > > ____USA_(FL)_May 2nd > > > Next Seminar dates: > (see http://www.jlcomp.demon.co.uk/seminar.html ) > > ____USA_(CA, TX)_August > > > The Co-operative Oracle Users' FAQ > http://www.jlcomp.demon.co.uk/faq/ind_faq.html > > > ----- Original Message ----- > To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> > Sent: 04 March 2003 13:38 > > > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Jonathan Lewis > 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: Tim Gorman 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).
