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Home -> Community -> Usenet -> c.d.o.server -> Re: log buffer growing and sga tunning
"Sybrand Bakker" <postbus_at_sybrandb.demon.nl> wrote:
>I wouldn't bother about 4 redo log space requests *per day*. It
there would
>have been 4 requests per hour, OK.
>The log_buffer issue has been discussed before here, and the
conclusion was
>a large log_buffer was actually having big detrimental effects
on
>performance. The absolute maximum was supposed to be 1M!
Well, I'm concerned about this because I have some daily process generating a LOT of redo (many inserts/updates), and my idea is to avoid redo log IOs - but, if 20 Mb of buffer isn't sufficient, I quit.
>You also have a very high log_files setting (255), which may
contribute to
>your problems.
This is the dafault value - what is the more apropriate value for the param ?
>Another obvious point is the 130M shared pool.
>Oracle recommends the complete SGA shouldn't make up more than
25-33 percent
>of complete physical memory, it looks like to me you are
probably already
>having a too big SGA, inducing paging and swapping on the O/S
side.
But i have 1 Gb, and Oracle is the only app in the box - this way, 250 Mb (the value of my SGA today) means 25% of the physical RAM. Moreover, the SO keep all the SGA in just one block, and there isn't paging - see below :
prod:/oracle/soft> ipcs -mb
IPC status from /dev/mem as of Wed Aug 2 08:46:41 GRNLNDST 2000
T ID KEY MODE OWNER GROUP SEGSZ
Shared Memory:
m 262144 0x580520ba --rw-rw-rw- root system 134217728 m 1 0x470410d9 --rw-r--r-- imnadm imnadm 48 m 2 0x580410d9 --rw-r--r-- imnadm imnadm 4096 m 3 0x4d0410d9 --rw-r--r-- imnadm imnadm 4096 m 4 0x490410d9 --rw-r--r-- imnadm imnadm 4096 m 5 0x500410d9 --rw-r--r-- imnadm imnadm 3222 m 6 0x450410df --rw-rw-rw- imnadm imnadm 96 m 7 0x430410df --rw-rw-rw- imnadm imnadm 97708 m 8 0x420410df --rw-rw-rw- imnadm imnadm 36028 m 9 0x410410df --rw-rw-rw- imnadm imnadm 42148 m 10 0x440410df --rw-rw-rw- imnadm imnadm 2844 m 262155 0x0827c4a3 --rw-r----- oracle dba 253640704 m 12 0x0d052a07 --rw-rw-rw- root system 1440prod:/oracle/soft>
prod:/oracle/soft> vmstat
kthr memory page faults cpu
----- ----------- ------------------------ ------------
[]s
Chiappa
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Received on Wed Aug 02 2000 - 00:00:00 CDT
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