... and we butt headlong into another fine myth, that is that the SGA must fit into one segment.
On Sunday 24 November 2002 15:53, Richard Ji wrote: > >if that SGA + user processes > shmmax the system will start swapping. > > That's not true. If your SGA is bigger than shmmax, it just means > the SGA will be fit into multiple shared memory segments. Doesn't > necessary mean the system will start swapping. Is the scan rate > going up? > > Richard > > -----Original Message----- > Sent: Saturday, November 23, 2002 1:49 PM > To: Multiple recipients of list ORACLE-L > > > Hi everyone, > > I was always under the impression that the only concern with shmmax was > that it be large enough for the SGA to fit into it. One of my System > Administrators has just told me that the individual user processes (i.e., > the PGA since we're not using multi-threaded server) get added to the SGA > and if that SGA + user processes > shmmax the system will start swapping. > > I haven't found anything to specifically address this issue on Metalink so > I though I'd throw it open. We've started experiencing system slowdown and > he says that increasing shmmax could resolve it. I'm skeptical (he also > suggested increasing SGA to decrease swapping which I told him in no > uncertain terms was nonsense). > > If anyone has a link to a note or white paper I'd appreciate that too. > > I've appended his email at the bottom. This slowdown seems to occur even > when there's virtually on oracle activity so I'm suspecting some other > cause. > > Thanks, > Jay Miller > > > > > nycsun1 and njsun7 has 6 GB of memory and only 2 GB of share memory. This > morning nycsun1 was very slow and I noticed that there was lots of swaping. > see vmstst and iostat below in red: > > procs memory page disk faults cpu > r b w swap free re mf pi po fr de sr s2 s4 s4 sd in sy cs us sy > id > 0 0 23 4366736 97528 1 2186 16 12 12 95520 0 0 0 0 0 1104 3330 974 11 8 > 81 > 0 0 23 4365992 96056 1 451 16 24 52 85968 3 0 0 0 0 935 847 416 3 1 > 96 > 0 0 23 4364712 95512 2 310 36 24 492 85968 68 0 0 0 0 1036 2183 670 13 4 > 84 > 0 0 23 4361568 95488 9 2264 0 76 964 95520 136 0 0 0 0 979 4065 607 12 6 > 82 > 0 0 23 4362384 96080 1 6 4 8 8 77376 0 0 0 0 0 975 465 457 2 1 > 97 > 0 0 23 4361944 95712 4 730 92 48 532 95520 64 0 0 0 0 1040 1859 734 8 3 > 89 > 0 0 23 4360424 95480 4 41 36 40 100 77376 7 0 0 0 0 986 1250 542 6 0 > 94 > 0 0 23 4361304 96096 3 264 76 36 88 88496 7 0 0 0 0 1037 942 665 5 3 > 92 > 0 0 23 4359680 95784 2 449 4 28 84 95520 8 0 0 0 0 922 1047 374 4 1 > 95 > 0 0 23 4359936 95464 2 544 4 20 332 95520 44 0 0 0 0 931 1095 384 2 2 > 96 > > /s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device > 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0 0 c2t6d0 > 0.0 34.5 0.0 270.0 0.2 13.8 6.7 399.5 6 44 c5t12d0 -- swap > disk > 0.0 34.5 0.0 270.0 0.5 10.7 15.5 309.4 18 39 c5t13d0 -- swap > disk > > > This shows that the system is not effectively using memory. I suggest > increasing the share memory to 4 GB so that DBAs can increase their memory > usage. Also set priority paging on. Priority paging will give application > first priority then free memory will be allocated to file cache( Solaris > 2.6 and 7. Solaris 8 is set dynamically). > > * ORACLE CONFIGS > set shmsys:shminfo_shmmax =2048000000 -- increase to 4096000000 > set shmsys:shminfo_shmmin=1 > set shmsys:shminfo_shmmni=300 > set shmsys:shminfo_shmseg=30 > set semsys:seminfo_semmap=500 > set semsys:seminfo_semmni=200 > set semsys:seminfo_semmns=2000 > set semsys:seminfo_semmsl=1000 > set semsys:seminfo_semmnu=500 > set semsys:seminfo_semume=150 -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Jared Still 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).
