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Memory usage, Solaris/DB11.2 [message #511898] Wed, 15 June 2011 18:58 Go to next message
John Watson
Messages: 4081
Registered: January 2010
Location: Global Village
Senior Member
Please can someone assist me with interpreting what top is telling me?
This is the memory config and usage within the instance:
xxsb> sho parameters memory

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
hi_shared_memory_address             integer     0
memory_max_target                    big integer 16G
memory_target                        big integer 14G
shared_memory_address                integer     0

xxsb> select round(sum(value)/1024/1024) from v$sesstat where
  2  statistic#=(select statistic# from v$statname where name='session pga memory');

ROUND(SUM(VALUE)/1024/1024)
---------------------------
                        452

xxsb> select round(sum(bytes)/1024/1024) from v$sgastat;

ROUND(SUM(BYTES)/1024/1024)
---------------------------
                       9276

xxsb>

and this is what top says:
load averages:  1.73,  1.52,  1.28;               up 0+05:54:02                                 19:37:15
75 processes: 73 sleeping, 2 on cpu
CPU states: 89.1% idle,  6.4% user,  4.5% kernel,  0.0% iowait,  0.0% swap
Kernel: 27289 ctxsw, 2050 trap, 16354 intr, 17325 syscall, 57 flt
Memory: 20G phys mem, 1021M free mem, 20G total swap, 20G free swap

   PID USERNAME NLWP PRI NICE  SIZE   RES STATE    TIME    CPU COMMAND
   968 oracle     24   0    0   17G   10G cpu/14 272:57  6.25% oracle
   884 oracle     15  52    0   16G 3270M sleep    8:01  1.89% oracle
   876 oracle      1  59    0   16G 3264M sleep    2:25  0.05% oracle
 10914 oracle      1  59    0 4504K 3712K cpu/7    0:00  0.03% top
   866 oracle      1 101  -20   16G 3261M sleep    0:51  0.02% oracle
   772 noaccess   18  59    0  167M  129M sleep    1:26  0.01% java
   886 oracle     19  59    0   16G 3270M sleep    0:21  0.01% oracle
   862 oracle      1  59    0   16G 3266M sleep    0:14  0.00% oracle

process 968 is j000, process 884 is lgwr, process 876 is dia0, 866 is vktm, 862 is pmon.

Our sysadmin is concerned that the system might start swapping when a few more non-Oracle processes start up. Is that going to happen?
I'm well below the memory_target at the moment, but that will probably change when more Oracle sessions connect: will that increase the requirement for RAM, or has it already been taken?
Do I need to be worried about the SIZE column of top, or is it the RES column all that matters? Is the difference between them available for use by other processes?

THanks for any advice.
Re: Memory usage, Solaris/DB11.2 [message #511900 is a reply to message #511898] Wed, 15 June 2011 19:10 Go to previous messageGo to next message
BlackSwan
Messages: 21941
Registered: January 2009
Senior Member
>Is that going to happen?
I seriously doubt the system will start swapping to a large amount.
"top" is a poor tool to use to judge RAM usage when Oracle is involved.
below will take 1 minute to complete & post your results back here

bcm@bcm-laptop:~$ vmstat 6 10
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 1  0      0 838632  82044 1996520    0    0    27    23  331  670  8  2 89  1
 0  0      0 838368  82052 1996552    0    0     0    33  616 1376  7  2 90  1
 0  0      0 838384  82060 1996552    0    0     0    34  537 1157  6  2 92  0
 0  0      0 838136  82076 1996552    0    0     0    36  567 1223  8  2 89  1
 2  0      0 843360  82084 1996552    0    0     0    21  462  973  5  2 92  1
 1  0      0 843392  82092 1996552    0    0     0    16  602 1286  8  1 90  0
 0  0      0 843144  82100 1996552    0    0     0    34  575 1228  7  2 90  1
 0  0      0 843128  82152 1996552    0    0     0    69  434  869  4  1 93  2
 0  0      0 842244  82168 1996552    0    0     0    41  618 1318  8  2 89  1
 1  0      0 836540  82176 1996556    0    0     1    69  555 1160  7  3 90  0
bcm@bcm-laptop:~$ 
Re: Memory usage, Solaris/DB11.2 [message #511901 is a reply to message #511900] Wed, 15 June 2011 19:16 Go to previous messageGo to next message
John Watson
Messages: 4081
Registered: January 2010
Location: Global Village
Senior Member
Thanks for replying, I appreciate it.
-bash-3.00$ vmstat 6 10
 kthr      memory            page            disk          faults      cpu
 r b w   swap  free  re  mf pi po fr de sr vc vc vc vc   in   sy   cs us sy id
 0 0 0 3881808 1745176 13 54 0  0  0  0  1  1  1 68 67 3239 3478 4765  5  2 93
 0 0 0 3219784 1221592 1  3  0  0  0  0  0  0  0 414 415 15805 17376 26361 6 4 90
 0 0 0 3218848 1221008 0  0  0  0  0  0  0  0  0 417 417 15817 17405 26467 6 4 90
 0 0 0 3205456 1207824 0  0  0  0  0  0  0  0  0 398 398 15146 17267 25168 6 4 90
 0 0 0 3184352 1186312 0  0  0  0  0  0  0  0  0 304 303 10447 15331 17042 6 4 90
 0 0 0 3190824 1189336 42 252 0 0  0  0  0  0  0 430 431 16684 18608 27816 6 5 89
 0 0 0 3175040 1173520 0  0  0  0  0  0  0  0  0 396 396 15214 17224 25232 6 5 89
 0 0 0 3155744 1154240 7 47  0  0  0  0  0  0  0 371 373 14226 16599 23624 6 4 89
 0 0 0 3129896 1128416 0  0  0  0  0  0  0  0  1 373 374 14438 16349 23905 6 4 90
 0 0 0 3089320 1088376 41 119 0 0  0  0  0  0  0 330 327 11475 16364 18847 6 5 89
-bash-3.00$




Re: Memory usage, Solaris/DB11.2 [message #511902 is a reply to message #511901] Wed, 15 June 2011 19:27 Go to previous messageGo to next message
BlackSwan
Messages: 21941
Registered: January 2009
Senior Member
darn your vmstat does not display same column headers as mine
"si" is "swap in"; "so" is "swap out"; "bi" is "blocks in"; & "bo" is "blocks out"
as long as si+so < bi+bo the RAM is not a system bottleneck
On any/every *NIX system "free RAM" goes to under 5% of total RAM; REGARDLESS of total RAM in the system.
Re: Memory usage, Solaris/DB11.2 [message #511981 is a reply to message #511902] Thu, 16 June 2011 07:29 Go to previous message
John Watson
Messages: 4081
Registered: January 2010
Location: Global Village
Senior Member
Thanks again.
I shall hope that it is safe to assume that the difference between memory_target and memory_max_target is definitely available for use by non-Oracle processes: if anyone can confirm or deny, or give me any other pointers, I would appreciate it.

John.

ps: "pointers" was meant to be a joke.
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