SGA & pga

Similar Questions

• SGA, PGA is greater than the memory and oracle does not work

  Hello

  Wrongly, I put the following:

  ALTER system SET sga_max_size = 1500M scope = spfile;

  ALTER system SET SGA_TARGET = 1400M scope = spfile;

  ALTER SYSTEM SET PGA_AGGREGATE_TARGET = 9000M scope = spfile;

  My total memory is 16 GB, Win8

  When I rebooted the oracle, he could not start and I m sure 100% that these sizes of memory are the problem.

  Now, I can not connect to the DB set these sizes of memory.

  How can I change the SGA, PGA, while the entire oracle is down? It is not only the DB instance that is nt working. It s the entire oracle.

  Is it possible to change the spfile from a text editor?

  I d appreciate your quick responses.

  Kind regards

  Hussien Sharaf

  Post edited by: 3008910

  Vidar, great recommendation.  There are cases where the spfile directly change can cause problems. If you happen who meet and the spfile is not usable, you can also create a new pfile of content in the journal of the alerts, start the instance by using the new file pfile, then make a copy of the pfile to the spfile.  Here are the basic steps if the spfile is corrupted and you need to create a new:

  (1) find the alerts log, copy the lines below the comment "parameters of the system with default values:" in a new file calledinit .ora and save the file in the directory by default (dbs or database) file.

  (2) make sure that the bad spfile is not in the directory of the file/start setting and start the Oracle service & the instance should now be available.  If you are not able to connect as "/" try to use sys / as sysdba

  (3) create a copy of the spfileinit .ora file: sql > create spfile from pfile;     -You can specify the directories, or leave the default value.

  (4) return & validate the parameters according to the directives of our discussion earlier.

  Hussien, I hope this helps.

  CP

• Allocation size SGA + PGA

  Hi all
  
  I have a server of the System Configuration with
  
  Size of RAM: 16 GB Ram & hard disk size 1 TB.
  
  I have installed Oracle 11 g R2 in the system server of
  
  I want to allocate memory dedicated for oracle...
  
  How can I calculate the size of the memory of the SGA + PGA TOUR for good performance...

  PL don't post duplicates - Reg:-SGA & PGA memory size allocation

• Oracle allows more memory than sga + pga

  Hi Experts,
  
  If I put 1 GB and 2 GB SGA pga then oracle could use more than 3 GB of RAM from the operating system.
  
  Thank you
  Please ignore if seems to be a very basic question...

  Yes.

  The PGA_AGGREGATE_TARGET is only a target. On a busy system, a system with often changing patterns of SQL, Oracle may try to assign a higher value.

  I assume you're on 32-bit Windows. You will hit ORA-4030 errors from time to time because Oracle under Windows is a single process (multi-threaded) and Windows limits the memory, the process can answer.
  I suggest you reduce your P_A_T.

  Hemant K Collette

• Oracle Concepts: Query processing SQL (SGA/PGA performance)

  Hello
  
  I need some clarification on my understanding, assume there is a query:

  SELECT t1.c1, t1.c2
  FROM t1, t2
  WHERE t1.c3 = t2.c1
  ORDER BY t1.c1;

  The user pointed out above the query and the following steps are performed:

  Syntax Check -in PGA
  Semantic Check -in PGA
  Shared Pool Check (unsuccessful) -in SGA
  Optimization (Hard Parse) -in SGA
  Row Source Generation (Hard Parse) -in SGA
  Execution - in SGA?

  User B sends a request even and following steps are performed:

  Syntax Check -in PGA
  Semantic Check -in PGA
  Shared Pool Check (successful) -in SGA
  (Soft Parse)
  Execution - in SGA?

  First question (general):
  I thought execution happens to the LMS, but sort, hash, or bitmaps merger happens in PGA (temporary segment), then it's a subset of execution that happens in the PGA to the user?
  
  Second question (for user B):
  Once check the shared pool is successful, and plan/data sets are already in SGA, so sort, hash, and/or merge bitmaps happen on these sets of data to the user of the PGA B?
  
  Kind regards
  Ankit Rouault
  http://oraclenbeyond.blogspot.in

  NVO wrote:
  Hello

  I need some clarification on my understanding, assume there is a query:

  SELECT t1.c1, t1.c2
  FROM t1, t2
  WHERE t1.c3 = t2.c1
  ORDER BY t1.c1;
  

  The user pointed out above the query and the following steps are performed:

  Syntax Check -in PGA
  Semantic Check -in PGA
  Shared Pool Check (unsuccessful) -in SGA
  Optimization (Hard Parse) -in SGA
  Row Source Generation (Hard Parse) -in SGA
  Execution - in SGA?
  

  User B sends a request even and following steps are performed:

  Syntax Check -in PGA
  Semantic Check -in PGA
  Shared Pool Check (successful) -in SGA
  (Soft Parse)
  Execution - in SGA?
  

  First question (general):
  I thought execution happens to the LMS, but sort, hash, or bitmaps merger happens in PGA (temporary segment), then it's a subset of execution that happens in the PGA to the user?

  Execution happens in the SGA (buffer cache), but no matter what kinds of these treatment as sorting is specific session and that is why it happens in the PGA for this user.

  >

  Second question (for user B):
  Once check the shared pool is successful, and plan/data sets are already in SGA, so sort, hash, and/or merge bitmaps happen on these sets of data to the user of the PGA B?

  Yes.

  That said, you can post a link that confirms that the syntax/semantics check occur in the PGA? As far as I know this isn't really a part of the PGA because code oracle itself stock grammar and would do it.

  Aman...

• SGA, PGA and other areas of memory

  Hi guys,.
  
  (I use 9i, with dedicated server mode, for a DSS system)
  
  I just want to know if my interpretation is correct.
  
  (1) when an instance starts, Oracle sets aside the amount of RAM specified by SGA_MAX_SIZE.
  (2) given that the PGA is located outside the LMS, Oracle also cancels PGA_AGGREGATE_TARGET.
  (3) so that the required total RAM is SGA_MAX_SIZE + PGA_AGGREGATE_TARGET
  (4) the SGA has a variable size. Because stuff like SHARED_POOL_SIZE and JAVA_POOL_SIZE may have a value specified, their size cannot grow. Therefore, the variable size is used to account for the other structures of memory as sql_area I can see on the page of Tom Kyte on SGA (links not working do not, so the address is http://asktom.oracle.com/pls/asktom/f?p=100:11:0:::P11_QUESTION_ID:365088445659))
  (5) If a database is about 85% of the SGA size is, would you say that is a size very bad CMS? (I know you guys hate rules of thumb, but any input on this would be always appreciated).
  
  Thank you

  It's confused me, I thought that each user is able to use up to the specified amount... If a user can go beyond PGA_AGGREGATE_TARGET, what's the point of this setting? Of course, Oracle must have an upper limit for the PGA, otherwise it could eventually consume all memory.

  First confusion PGA_AGGREGATE_TARGET is not by user, is limited for all processes associated with the instance server. Always book enough memory on the OS to ensure that you can honor the value.
  http://68.142.116.68/docs/CD/B19306_01/server.102/b14237/initparams157.htm#REFRN10165

  There are cases where Oracle on will provide PGA if PGA_AGGREGATE_TARGET set too low.
  For example.

  SELECT * FROM V$PGASTAT;The output of this query might look like the following:
  
  NAME                                                          VALUE UNIT-------------------------------------------------------- ---------- ------------aggregate PGA target parameter                             41156608 bytesaggregate PGA auto target                                  21823488 bytesglobal memory bound                                         2057216 bytestotal PGA inuse                                            16899072 bytestotal PGA allocated                                        35014656 bytesmaximum PGA allocated                                     136795136 bytestotal freeable PGA memory                                    524288 bytesPGA memory freed back to OS                              1713242112 bytestotal PGA used for auto workareas                                 0 bytesmaximum PGA used for auto workareas                         2383872 bytestotal PGA used for manual workareas                               0 bytesmaximum PGA used for manual workareas                       8470528 bytesover allocation count                                           291bytes processed                                          2124600320 bytesextra bytes read/written                                   39949312 bytescache hit percentage                                          98.15 percent
  

  the count of distribution: this statistic is cumulative since instance startup. Too PGA Award in memory can occur if the value of PGA_AGGREGATE_TARGET is too small to accommodate the other PGA component in the previous equation, more the minimum memory required to run the load of work area. In this case, Oracle cannot honor PGA_AGGREGATE_TARGET initialization parameter and additional PGA memory should be allocated. In the case of over-allotment, you must increase the value of PGA_AGGREGATE_TARGET using the information provided by the view of advice V$ PGA_TARGET_ADVICE.

  http://68.142.116.68/docs/CD/B19306_01/server.102/b14211/memory.htm#i49320

  I'm still very confused about SHARED_POOL_SIZE. If I put SHARED_POOL_SIZE to 100M, and according to you, guys, that can grow to 100 M, so what's the point of having this setting in the first place?

  Thank you

  No, shared pool does not in itself, unless you use alter system to change. It's the dynamic sense, you don't need to restart the example to change. In the earlier version, you must restart the instance to resize the shared pool and the buffer cache.

  Oracle makes this possible by introducing setting SGA_MAX_SIZE in 9i.
  Before 9i, SGA is essentially BUFFER_CACHE + SHARED POOL + a few other components. Oracle allocate memory from the OS at startup function db_block_size and db_block_buffers shared_pool_size etc. So change the any of these settings for example, must restart.
  With SGA_MAX_SIZE, Oracle will allocate always SGA_MAX_SIZE initially, for example, 500M, you can define db cache and share setting as small as 200 M + 200 M pool, the 100M unused will be reported as free CMS, that allow to increase the shared pool and buffer cache later and also to provide a hold space released place if these setting reduced.

• How to set the SGA / PGA or memory target for the database

  Hello

  We use on AIX 5.1,6.1, oracle 9i, 10g, 11g

  Currently, we manage the databases on the default memory which was chosen at the time of the creation of the databases.

  Now the application owner want to host multiple databases on the same server, so they ask the

  rough idea on the memory required for each database,

  How we calculate the amount of memory required for each database.

  Thank you

  that recommend the SGA ADVISOR?

• SGA PGA screen

  10.2 OEM, there's a clever display that showed the LMS used, and how memory is allocated within each of the components.

  I looked everywhere in em12c for this function, but miss me for some reason any.

  Can someone point me in the right direction?

  From the homepage of target database, click Performance > advisors memory

  You will see the current allocation at the bottom of the screen.

• Size of SGA and PGA

  Hi all
  
  I have a question.
  What are the best criteria to define the size of the SGA and PGA size in oracle 10g? and size in oracle 11g memory_target?
  Is related to the size of the data? What is the criteria and factors which affects setting the size of the SGA, PGA (10 g) and memory_target (11 g)?
  
  Kind regards

  Hello

  How can identify the best value for V memory_target $ MEMORY_TARGET_ADVICE?

  We can take the example below:

  SQL> select * from v$memory_target_advice;
  
  MEMORY_SIZE MEMORY_SIZE_FACTOR ESTD_DB_TIME ESTD_DB_TIME_FACTOR    VERSION
  ----------- ------------------ ------------ ------------------- ----------
          393                ,75        17909              1,0004          0
          524                  1        17902                   1          0
          655               1,25        17900               ,9999          0
          786                1,5        17897               ,9997          0
          917               1,75        17897               ,9997          0
         1048                  2        17897               ,9997          0
  

  You can see that 786 MB ESTD_DB_TIME_FACTOR beyond cannot be improved (it stuck here to 0.9997). So I may be updated (in this example) the MEMORY_TARGET 786 MB, I won't have any advantage to further increase.

  Hope this helps.
  Best regards
  Jean Valentine

• What is sga and pga configuration set up

  Hi Expert,
  
  Please help me with my question
  
  What is the exact configuration sga, pga and other setting
  
  Win2003 operating system 32-bit and oracle 8i
  
  64 GB of RAM
  database size 70 GB
  processor 2.13 ghz
  
  BMG =
  PGA =
  db_block_buffers =
  shared_pool_size =
  LARGE_POOL_SIZE =
  log_buffer =
  DB_BLOCK_SIZE =
  sort_area_size =
  sort_area_retained_size =

  user12255952 wrote:
  my hit ratio is low 76
  So what can I do

  What ratio of hit?

• Question of PGA

  Hello

  Oracle 11.2.0.3.0

  I have memory_target = 15G

  That is why in the database, pga_aggregate_target = 0

  But I can see from v$ pgastat, aggregation PGA target = 5637144576 parameter = Mo 5673 .

  Statspack shows

  Statistical memory Begin End

  ~~~~~~~~~~~~~~~~~                ------------ ------------

  Host Mem (MB): 31,440.3 31 440,3

  Use of LMS (MB): 15,291.4 15 291,4

  PGA use (MB):                          1,722.1      1,698.8

  Host % Mem used for SGA + PGA: 54.0 54.1

  PGA Aggr target histogram DB/Inst: PIVR01/PIVR01 snaps: 8610-8612

  -> Optimal performances are purely in memory operations

  High low

  Execs Total optimum optimum optimum Execs 1 pass Execs M-Pass Execs

  ------- ------- -------------- ------------- ------------ ------------

  2K      4K                     5,036          5,036            0              0

  64K    128K                       14               14            0              0

  128K    256K                      78              78             0              0

  512 K 1024 K 174 174 0 0

  1M      2M                      164            164            0              0

  4M      8M                           4               4             0              0

  256M 512M                      2               1             1              0

       1G      2G                             2               0             2              0

  
  

  Memory PGA Advisory DB/Inst: PIVR01/PIVR01 end Snap: 8612

  --> When using automatic memory management, choose at least a value of pga_aggregate_target

  where Estd PGA Overalloc Count is 0

  Estd estd Extra

  AGGR PGA W/A MB time Estd Estd PGA PGA

  Target size W/A MB read/written to deal with Cache Overalloc

  Factr EST (MB) treated disc bytes (s) % number of access

  ---------- ------ -------------- -------------- ---------- ------ ----------

  672 0.1 427 978 214.7 522 063 45.0 3 481

  1 344 0.3 427 978 514 547 213,0 45.0 3 320

  2 688 0.5 427 978 90 681 117.2 83,0 0 * advised a minimum size to fit all executions in memory        

  4 032 0.8 427 978 84 797 115.9 83,0 0

  5 376 1.0 427 978 115,3 82 105 84.0 0 * size current target which we fail to

  6 451 1.2 427 978 114,0 76 674 85.0 0

  7 526 1.4 427 978 114,0 76 674 85.0 0

  8 602 1.6 427 978 114,0 76 674 85.0 0

  
  

  1. why PGA memory grows no more than 2 GB to cope with this and be able to run the SQL all in memory, even if the target is set at 5673 MB?

  2. do I need to manually set pga_aggregate_target = 2688 M with memory target = 15 G?

  
  

  Thanks for your time
  

  1938071 wrote:

  I got your point, but the bottom implies that there is 2 SQL executions which do not completely held in memory of the PGA and must be partially exchanged on temporary slow disk. The size of the book that does this is between 1-2 GB.

  So if I 5673 MB allocated total setting target PGA in v$ pgastat, why is he not use it... This part confuses me

  Target histogram Aggr PGA

  -> Best executions are purely in memory operations

  High low

  Execs Total optimum optimum optimum Execs 1 pass Execs M-Pass Execs

  ------- ------- -------------- ------------- ------------ ------------

  2K      4K                     5,036          5,036            0              0

  64K    128K                       14               14            0              0

  128K    256K                      78              78             0              0

  512 K 1024 K 174 174 0 0

  1M      2M                      164            164            0              0

  4M      8M                           4               4             0              0

  256M 512M                      2               1             1              0

       1G      2G                             2               0             2              0

  The pga_aggregate_target did NOT previously assigned, it is a (soft) limit on the total memory that can be allocated dynamically. Given that you have defined the memory_target to 15 GB, Oracle can only grow the total allocation of the PGA to 5G by reducing the rest of its endowment (in large part the shared pool and the buffer cache) to 10 GB.

  It is a necessary part of the algorithm of automatic memory management that it would decide if the time saved by the growth of the component of the PGA is greater or less than the time lost by the decline of the shared pool and the cache buffers.  You could imagine that doing a few GB of bed and writes temporary files for one or two is probably much faster that 2 GB buffer cache dumping and ending with a large number of random to block reads as a side effect.

  -If you have a CPU bottleneck then hit a very large size on disk may be the best use of resources: large sorts in memory can we a lot of CPU.

  Concerning

  Jonathan Lewis

• PGA & auto SAG

  I'm confused on settings of parameter memeory in 11g on windows server 2003. I have disable automatic memeory management memory_target zero adjustment. I assign 4900 M PGA_Arregate_taget, SGA_MAX_TARGET = 4500M SGA_TARGET 4000 M. now, I wanted to switch the automatic management of memory for this I set memeory_target and memeory_max_target 9Gb of the 12 GB Ram. But when I ask. display the parameter sga, pga, it shows still not all of the values that I put the last time. I restart the instance. Kindly tell me I use automatic memory management or not?

  Hello..

  Sga_max_target set to zero. In 10g where we use sga_target, we set the sga_max_target value to set the limit, now in 11g, we define memory_max_target as we put memory_target. There is no need to define sga_max_target

  Anand

• session_cached_cursor

  
  Hello

  I use the suite of applications (from the oracle documentation) to check session_cached_cursors.

  I need to increase session_cached_cursors?  Know if it would be part of the SGA and PGA? It must be that the amount of memory in this case increases to place cursors? Work on 11 GR 2.

  If it is independent of multiple sessions created for the same user?

  Percent found in the cache is too high, I don't know why...

  Please provide suggestions.

  A.value SELECT curr_cached, p.value max_cached, s.username, s.sid, s.serial # FROM v$ sesstat a, v$ statname b, v$ session s, v$ parameter p 2
  WHERE a.statistic # b.statistic = #, s.sid = a.sid and a.sid = and sid AND p.name = 'session_cached_cursors'
  AND b.name = 'session cursor cache count ';

  curr_cached max_cached username sid, serial #.
  299 300 211 28771 PMS

  
  SELECT cach.value cache_hits, prs.value all_parses,
  Round ((cach. Value / PRS.value) * 100, 2) "% found in the cache.
  V $ sesstat cach, v$ sesstat prs, v$ statname nm1, v$ statname nm2
  WHERE cach.statistic # = nm1.statistic #.
  AND nm1.name = 'session cursor cache hits ".
  AND prs.statistic #= nm2.statistic #.
  AND nm2.name = 'analysis count (total)'
  AND cach.sid cach.sid = & sid and prs.sid =;

  cache_hits all_parses % found in the cache
  36012 683 5272.62

  Hi Don,

  > My cursors opened for the session are about 330.

  So if you want to keep more than 330 cursors open, you need to increase and open_cursors session_cached_cursors. However, if you ever notice the cursor manipulation depends on your application and you should not focus on ratios, but rather on the response time which is devoted to the analysis of soft (latch, lock, etc.).

  > I just activated automatic memory and configure the settings memory_max_target and memory_target. I can't ignore sga, pga components now?

  How should we know? If you set big enough memory_target and Oracle does its job of automatic memory management right-, then Yes.

  > cursor_sharing is set to EXACT, what I need to change that to FORCE to get the slider adjustment... sharing?

  First of all, to answer the question: is your application using the cursor cache in the case of PL/SQL cursor or cursor in the session. Then, you must answer the question, if ACS applies in your case. However you should also consult the documentation to get the idea behind ACS as mentioned parameter has nothing (directly) to do with the ACS. It is no longer relevant in the case of literals, but if set you it in the context to your question session_cached_cursors you probably rather a problem of implementation of request a matter of setting of database.

  Concerning

  Stefan

• Need help for analysis "plan and background events waiting" on the report statspack for oracle database 11.2.0.4 on AIX

  HI: I analyze the STATSPACK report: this is the "volume test" on our UAT server for most of entry or "bind variables".  Our shared pool is well used in oracle.  Recovery of Oracle logs is not configured properly on this server, as in "Top 5 events of waiting", there are 2 for Oder.

  I need to know what other information may be digging from of 'waiting in the foreground events' & ' background waiting events ", and which can help us better understand, in combination of ' Top 5 wait event, that how did the server test /?  It could be overwhelming. wait events, so appreciate useful diagnostic or analyses.  Database is oracle 11.2.0.4 updated from 11.2.0.3 on IBM AIX 64-bit, level 6.x system power

  
  

  STATSPACK report

  
  DB Id Instance Inst Num Startup Time Release RAC database

  
  

  ~~~~~~~~ ----------- ------------ -------- --------------- ----------- ---

  700000XXX XXX 1 22 April 15 12:12 11.2.0.4.0 no.

  
  Host name Platform CPU Cores Sockets (G) memory

  ~~~~ ---------------- ---------------------- ----- ----- ------- ------------

  dXXXX_XXX AIX-Based Systems (64-2 1 0 16.0)

  
  Snapshot Id Snap Snap time Sessions Curs/Sess comment

  ~~~~~~~~    ---------- ------------------ -------- --------- ------------------

  BEGIN Snap: 5635 22 April 15 13:00:02 114 4.6

  End Snap: 5636 22 April 15 14:00:01 128 8.8

  Elapsed time: 59.98 (mins) Av law Sess: 0.6

  DB time: 35,98 (mins) DB CPU: 19,43 (mins)

  
  Cache sizes Begin End

  ~~~~~~~~~~~       ---------- ----------

  Cache buffer: block 2 064 M Std size: 8 K

  Shared pool: 3 072 M Log Buffer: 13 632 K

  Load profile per second per Transaction per Exec by call

  ~~~~~~~~~~~~      ------------------  ----------------- ----------- -----------

  DB Time (s): 0.0 0.6 0.00 0.00

  DB CPU: 0.0 0.3 0.00 0.00

  Size: 458 720,6 8,755.7

  Logical reads: 245,7 12 874,2

  Block changes: 1 356.4 25.9

  Physical reads: 6.6 0.1

  Physical writings: 61.8 1.2

  The user calls: 38.8 2 033,7

  Analysis: 286,5 5.5

  Hard analysis: 0.5 0.0

  Treated W/A Mo: 1.7 0.0

  Logons: 1.2 0.0

  Runs: 801,1 15.3

  Cancellations: 6.1 0.1

  Operations: 52.4

  
  Indicators of the instance

  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  Buffer % Nowait: 100.00 do NoWait %: 100.00

  Buffer % success: 99.98% W/A optimal, Exec: 100.00

  Library success %: 99,77% soft Parse: 99.82

  Run parse %: 64.24 latch hit %: 99.98

  Analyze the CPU to analyze Elapsd %: 53.15% Non-Parse CPU: 98.03

  
  Shared pool statistics Begin End

  ------  ------

  % Memory use: 10.50 12.79

  % SQL with executions > 1: 69,98 78,37

  % Memory for SQL w/exec > 1: 70.22 81,96

  Top 5 timed events Avg % Total

  ~~~~~~~~~~~~~~~~~~                                                   wait   Call

  Event waits time (s) (ms) time

  ----------------------------------------- ------------ ----------- ------ ------

  CPU time                                                       847          50.2

  ENQ: TX - 4 480 97 434 25.8 line lock conflict

  Log file sync 284 169 185 1 11.0

  log file parallel write 299 537 164 1 9.7

  log file sequential read 698 16 24 1.0

  Host CPU (processors: 2 hearts: Sockets 1: 0)

  ~ ~ ~ Medium load

  Begin End User System Idle WIO WCPU

  ------- -------   ------- ------- ------- ------- --------

  1.16 1.84 19.28 14.51 66.21 1.20 82.01

  
  Instance of CPU

  ~~~~~~~~~~~~                                       % Time (seconds)

  -------- --------------

  Host: Time (s) Total: 7,193.8

  Host: Availability of time processor (s): 2,430.7

  % of time host is busy: 33.8

  Instance: Time processor Total (s): 1,203.1

  % Busy CPU used, for example: 49.5

  Instance: Time of database total (s): 2,426.4

  % DB time waiting for CPU (resp. resources): 0.0

  
  Statistical memory Begin End

  ~~~~~~~~~~~~~~~~~                ------------ ------------

  Host Mem (MB): 16,384.0 16 384,0

  Use of LMS (MB): 7,136.0 7 136,0

  Use of PGA (Mo): 282.5 361.4

  Host % Mem used for SGA + PGA: 45.3 45.8

  Foreground wait events DB/Inst: XXXXXs Snaps: 5635-5636

  -> Only events with wait times Total (s) > =.001 are indicated

  --> sorted by Total desc waiting time, waits desc (idle last events)

  
  AVG % Total

  % Tim Total wait Wait Wait call

  Event is waiting for the time (s) (ms) /txn times

  ---------------------------- ------------ ---- ---------- ------ -------- ------

  ENQ: TX - line lock 4 480 0 434 97 contentio 0,0 25.8

  284 167 0 185 1 file synchronization log 1.5 11.0

  File I/O 8 741 of disk 0 4 operations 0.0 0.2

  direct path write 0 13 247 3 0.1 0.2

  DB file sequential read 6 058 0 1 0.0 0.1

  buffer busy waits 1 800 0 1 1 0,0.1

  SQL * Net more data to the client 29 161 0 1 0.2 0.1

  direct path read 7 696 0 1 0.0 0.0

  db file scattered read 316 0 1 2 0,0.0

  latch: shared pool 144 0 0 2 0,0.0

  Initialization of 30 0 0 3 0,0.0 CSS

  cursor: hand 10 0 0 9 0,0.0 S

  lock row cache 41 0 0 2 0,0.0

  latch: rank objects cache 19 0 0 3 0,0.0

  log file switch (private 8 0 0 7 0,0.0 str

  library cache: mutex X 28 0 0 2 0,0.0

  latch: cache buffers chains 54 0 0 1 0,0.0

  free lock 290 0 0 0.0 0.0

  sequential control file read 1 568 0 0 0.0 0.0

  switch logfile (4 0 0 6 0,0.0 control point

  Live sync 8 0 0 3 0,0.0 road

  latch: redo allocation 60 0 0 0 0.0.0

  SQL * Net break/reset for 34 0 0 1 0,0.0 customer

  latch: enqueue hash chains 45 0 0 0 0.0.0

  latch: cache buffers lru chain 7 0 0 2 0,0.0

  latch: allowance 5 0 0 1 0,0.0 session

  latch: object queue header 6 0 0 1 0,0.0 o

  Operation of metadata files ASM 30 0 0 0 0.0.0

  latch: in memory of undo latch 15 0 0 0.0 0.0

  latch: cancel the overall data 8 0 0 0 0.0.0

  SQL * Net client message 6 362 536 0 278 225 44 33.7

  jobq slave wait 7 270 100 3 635 500 0.0

  SQL * Net more data to 7 976 0 15 2 0,0 clien

  SQL * Net message to client 6 362 544 0 8 0 33.7

  -------------------------------------------------------------

  Context of the DB/Inst events waiting: XXXXXs clings: 5635-5636

  -> Only events with wait times Total (s) > =.001 are indicated

  --> sorted by Total desc waiting time, waits desc (idle last events)

  AVG % Total

  % Tim Total wait Wait Wait call

  Event is waiting for the time (s) (ms) /txn times

  ---------------------------- ------------ ---- ---------- ------ -------- ------

  log file parallel write 299 537 0 164 1 1.6 9.7

  log file sequential read 698 0 16 24 0.0 1.0

  db file parallel write 9 556 0 13 1 0,1.8

  146 0 10 70 0,0.6 startup operating system thread

  control file parallel write 2 037 0 2 1 0,0.1

  Newspaper archive e/s 35 0 1 30 0,0.1

  LGWR wait for redo copy 2 447 0 0 0.0 0.0

  async file IO DB present 9 556 0 0 0.1 0.0

  DB file sequential read 145 0 0 2 0,0.0

  File I/O disk 349 0 operations 0 0.0 0.0

  db file scattered read 30 0 0 4 0,0.0

  sequential control file read 5 837 0 0 0.0 0.0

  ADR block lu file 19 0 0 4 0,0.0

  Block ADR file write 5 0 0 15 0,0.0

  direct path write 14 0 0 2 0,0.0

  direct path read 3 0 0 7 0,0.0

  latch: shared pool 3 0 0 6 0,0.0

  single log file write 56 0 0 0.0 0.0

  latch: redo allocation 53 0 0 0 0.0.0

  latch: 1 0 0 3 0,0.0 active service list

  free latch 11 0 0 0 0.0.0

  CPI of RDBMS 5 314 523 57 189 182 1.7 message

  Space Manager: slave wa slowed 4 086 88 18 996 4649 0.0

  DIAG idle wait 7 185 100 1000 7 186 0.0

  Streams AQ: waiting time 2 50 4 909 # 0,0

  Streams AQ: qmn slowed slave 129 0 3 612 28002 0.0 w

  Streams AQ: Coordinator of the 258 50 3 612 14001 0,0 qmn

  SMON timer 2 43 3 605 83839 0.0

  PMON timer 99 1 199 2999 3 596 0.0

  SQL * Net client message 17 019 0 31 2 0.1

  SQL * Net message to client 12 762 0 0 0.1 0

  class slaves wait 28 0 0 0 0.0

  Thank you very much!

  Hello

  I think that your CPU is overloaded by your stress tests. You have one VCPU with 2 wires (2 LCPU), right? And the load average is greater than one. You have time DB which is not counted in (CPU time + wait events) and which comes no doubt from time spent in the runqueue.

  > Oracle recovery logs is not properly configured on this server, as in "Top 5 events of waiting", there are 2 for oder

  It is an error in statspack for show "log file parallel write here." This moment is historical and is included in 'log file sync '. And I don't think you have to redo misconfiguration. Waiting for 1ms to commit is ok. In OLTP you should have more than one validation in a user interaction so that the user don't worry not about 1 m in batch mode, unless you commit to each row, 1 DC to commit should not increase the total execution time.

  The fact that you have a lot of line lock (enq: TX - line lock conflict) but very little time (on average 97 ms) is probably a sign that testers are running simultaneously a charge affecting the same data. Their set of test data is perhaps too simple and short. An example: when stress tests of an order entry system if you run 1000 concurrent sessions, ordering the same product to the same customer, you can get this kind of symptoms, but the test we unrealistic.

  It's a high activity of 2000 calls per second, 52 transactions per second, user. But you also have low average active sessions, so the report probably covers a period of non-uniform activity, which makes the averages without meaning.

  So note to tell about the events of waiting here. But we don't have any info about 39% of DB time devoted to the CPU which is where something can be improved.

  Kind regards

  Franck.

• Physical RAM

  And, Yes, I read the fine manual.  Honest.

  What is structures of memory the current Oracle WRT to the 'guidelines' as a percentage of physical RAM for the database server?

  For example, if I have a compute node Exadata with 256 GB of RAM, how much this physical RAM can realistically / safely use?

  I know in days passes, recommendation of Oracle used 50% of the total RAM, but I'm sure that the operating system does not need to 128 GB of RAM, etc.

  I think an approximate indication of 75% must be with Exadata model nodes:

  -with 72 GB of RAM - 54 GB of RAM allocated to the database instance SGA / PGAs with 18 GB left.

  -with 256 GB of RAM - 192 GB of RAM allocated to the database instance SGA / PGAs with 64 GB of RAM left.

  This gives flexibility to the case where the PGAs hungry and take more of PGA_AGGREGATE_TARGET, but not to lose all this beautiful, expensive memory.

  Thoughts?

  Mark
  

  Hi Mark,

  I've seen the 80% number thrown around when it comes to allication memory (MOS doc 223730.1 for example), but these guidelines are from when the servers had a lot less memory.  Assuming that you use huge pages (and you should!), you could probably get away with aid still more: on a server of 256 GB, same allocate up to 90% of the leaves more than 25 GB of RAM for the operating system.

  Marc