Re: ora_dbw eat 900MB memory, an user process eat 1GB memory

Yes, this is perfectly reasonable depending on the size of your buffercache.

In linux (and all unixes), the used memory, reported in /proc (and thus reported in top) per process, accounts for private memory, and all touched shared memory pages.

for processes like the dbwr (which will touch much of the pages of your buffercache most probably) this means that the reported used memory will grow initially, and be reported as you see.

frits

On Thu, Nov 13, 2008 at 11:42 AM, Ujang Jaenudin <ujang.jaenudin_at_gmail.com>wrote:

> lists,
>
> from below data, please let me know :
> - why 7 user process eat memory 1GB each?
> - is it reasonable dbw occupy 900MB memory?
>
>
> linux rhel 4u4 32bit
> physical memory 6GB
> SGA 1.3 GB
>
> top:
> Mem: 6227912k total, 6189032k used, 38880k free, 19616k buffers
> Swap: 10482372k total, 44732k used, 10437640k free, 5747824k cached
>
>
> vmstat:
> r b swpd free buff cache si so bi bo in cs us sy id
> wa
> 0 0 44224 50088 23824 5784936 0 1 183 20 0 4 1 0
> 97 1
> 0 0 44224 50088 23848 5784912 0 0 0 46 8715 8421 3 1
> 96 0
> 0 0 44224 51880 23848 5784912 0 0 0 28 4569 3952 1 0
> 99 0
> 1 0 44224 51496 23868 5785152 0 0 58 84 5364 4653 3 1
> 95 1
>
>
> select sum(maxmem)/1024/1024 MB_TOTAL from (
> select se.sid,n.name,
> max (se.value) maxmem
> from v$sesstat se,
> v$statname n
> where n.statistic# = se.statistic#
> and n.name in ('session pga memory','session pga memory max',
> 'session uga memory','session uga memory max')
> group by n.name,se.sid);
>
>
> MB_TOTAL
> ----------
> 878.814056
>
>
>
> cat /proc/meminfo
>
> MemTotal: 6227912 kB
> MemFree: 50656 kB
> Buffers: 15068 kB
> Cached: 5773652 kB
> SwapCached: 4080 kB
> Active: 4690588 kB
> Inactive: 1324744 kB
> HighTotal: 5373740 kB
> HighFree: 2752 kB
> LowTotal: 854172 kB
> LowFree: 47904 kB
> SwapTotal: 10482372 kB
> SwapFree: 10438312 kB
> Dirty: 160 kB
> Writeback: 0 kB
> Mapped: 1394784 kB
> Slab: 57868 kB
> CommitLimit: 13596328 kB
> Committed_AS: 2343036 kB
>
>
> ps -e -orss=,args= | sort -b -k1,1n | pr -TW$COLUMNS
> -- rss is in KB
> -- the total (after sum through spreadsheet), it occupy 16GB !!!
>
> 992840 ora_dbw0_BRGDB
> 1012332 oracleBRGDB (LOCAL=NO)
> 1026448 oracleBRGDB (LOCAL=NO)
> 1030392 oracleBRGDB (LOCAL=NO)
> 1030572 oracleBRGDB (LOCAL=NO)
> 1031408 oracleBRGDB (LOCAL=NO)
> 1033576 oracleBRGDB (LOCAL=NO)
> 1053928 oracleBRGDB (LOCAL=NO)
> 756244 ora_smon_BRGDB
> 825984 oracleBRGDB (LOCAL=NO)
> 838876 oracleBRGDB (LOCAL=NO)
> 849900 oracleBRGDB (LOCAL=NO)
> 911112 oracleBRGDB (LOCAL=NO)
> 954036 oracleBRGDB (LOCAL=NO)
> 989808 oracleBRGDB (LOCAL=NO)
> 133480 ora_mmon_BRGDB
> 244200 oracleBRGDB (LOCAL=NO)
> 587080 oracleBRGDB (LOCAL=NO)
> 599804 oracleBRGDB (LOCAL=NO)
> 29808 oracleBRGDB (LOCAL=NO)
> 48432 ora_q001_BRGDB
> 52188 ora_ckpt_BRGDB
> 53208 ora_mmnl_BRGDB
> 66012 ora_q000_BRGDB
> 82980 oracleBRGDB (LOCAL=NO)
> 86908 oracleBRGDB (LOCAL=NO)
> 96992 ora_cjq0_BRGDB
> 21032 oracleBRGDB (LOCAL=NO)
> 22332 oracleBRGDB (LOCAL=NO)
> 22552 ora_arc1_BRGDB
> 22640 ora_arc0_BRGDB
> 23088 ora_reco_BRGDB
> 27720 ora_mman_BRGDB
> 28824 ora_lgwr_BRGDB
>
>
> --
> thanks and regards
> ujang | oracle dba
> jakarta | http://ora62.wordpress.com
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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