Similar Questions

• Tuning PGA Cache Hit Percantage

  Hi Experts,
  
  I need your help to increase my cache hit percentage
  
  My version of DB is 9.2.0.1.0 with 8 GB of memory
  
  The SGA size: 560MB
  Overall target of PGA: 128 MB
  
  and put in Cache Hit %: 64,74%
  
  How do I hide my PGA increase %
  
  Here are the results of some Tuning scripts that I found on the web.
  
  Select the name, the value from v$ pgastat;
  
  VALUE NAME
  PGA 134217728 overall target setting
  overall target of the PGA 62281728 auto
  related global memory 6710272
  Total PGA inuse 67956736
  Allocated total PGA 119108608
  PGA maximum allowed 140296192
  total memory of PGA freeable 7208960
  PGA memory freed to OS 7361462272
  Total PGA used to auto workareas 2932736
  Maximum PGA used to workareas auto 25807872
  Total PGA used for manual workareas 0
  Maximum PGA used for manual workareas 0
  during the assignment of the count 0
  the treated bytes 29607550976
  extra bytes read/written 16256915456
  cache hit percentage 64,55
  
  
  Select name c1, c2 count, decode (total, 0, 0, round(count*100/total)) c3
  (select name, count, (total (value) value on (()) sum of v$ sysstat where name like 'activities exec %');
  
  C1 c2 c3
  activities the executions - optimal 475834 100
  executions - onepass 323 activities 0
  activities the executions - multipass 3 0
  
  SELECT turn target_mb (PGA_TARGET_FOR_ESTIMATE/1024/1024),
  ESTD_PGA_CACHE_HIT_PERCENTAGE cache_hit_perc,
  ESTD_OVERALLOC_COUNT
  V $ pga_target_advice;
  
  TARGET_MB CACHE_HIT_PERC ESTD_OVERALLOC_COUNT
  16                     44                     2177
  32                     45                     1923
  64                     68                     133
  96                     72                     0
  128                     73                     0
  154                     81                     0
  179                     81                     0
  205                     81                     0
  230                     81                     0
  256                     81                     0
  384                     81                     0
  512                     81                     0
  768                     95                     0
  1024                     95                     0
  
  Please help me to increase the % of success.

  But still, you can find the optimal plan and tell your developers to implement depends on this plan...

• Foglight | Monitoring Exchange | EXC IS a Database Cache Hit percentage

  Hello

  In Foglight 5.6.5, for monitoring of Exchange, 'EXC IS Hit percentage of Database Cache' setting alarm message is null.

  No chance, it is a pasive cluster node?

  There is this article

  https://support.quest.com/SolutionDetail.aspx?ID=SOL108087&PR=Foglight

  108087 knowledge article

  RSS subscription

  close

  The solution that you want to subscribe covers a number of software products from Dell. Please choose the one that is of primary interest;

  
   

  Foglight

  Foglight for virtualization Enterprise Edition

  • Return

  • Title

    Rule of Database Cache % Hit EXC triggers alarm for the node of cluster pasive despite no activity

  • Description

  Rule of Database Cache % Hit EXC triggers alarm for cluster node paasive despite no database activity

  • Resolution

  Default ID EXC-646 was recorded and will be evaluated for a future release

  • ID of default

  EXC-646

• Cache HIT

  Hello

  We activated the CACHE of OBIEE 11 g through the FMW. Now, how would I know that the request hit the cache

  Run a query and analysis and look at the log file (nqquery.log). If you see the name of the physical table and then he went to the database, then he got the information from the cache. There should also be cache hit 1 in the journal against cache press 0.

• How to increase! Buffer Cache Hit Ratio

  Hi all
  
  my database performance is low how to increase the buffer Cache Hit Ratio
  
  Database version: 8.1.7.0.0
  ~ Data upward since: 09:56:23, September 23, 2010
  ! Buffer Cache Hit Ratio: 81.6157
  ~ The library Cache Miss Ratio: 0.03
  ~ Dictionary Cache Miss ratio: 6.6979
  
  [Use of the shared pool] Exec time 0 seconds
  ~ Total unused Mb: 251.88
  ~ Total MB used: 98.12
  ~ MB total: 350
  ~ % Pool used: 28.04

  Buffer Cache Hit Ratio is an indicator of sense of the performance of the system.
  Are there users complain? If there are no complaints, there is also no problem.

  The best way to increase the buffer Cache Hit Ratio is executing statspack identify offensive SQL and to grant this SQL offensive.

  ----------
  Sybrand Bakker
  Senior Oracle DBA

• Database buffer cache hit ratio is less than 90%

  Hi all
  
  For the following query I get the bottom 90%
  
  SELECT ROUND (((1-(phy.) VALUE /(cur.) VALUE con. ((VALUE))) * 100), 2) "HIT RATIO" +.
  OF SYS.v_$ sysstat news,.
  SYS.v_$ sysstat con,.
  SYS.v_$ sysstat phy
  WHERE cur.NAME = 'db block gets. "
  AND con.NAME = "becomes" compatible
  AND phy.NAME = 'physical reads. "
  
  RATE
  ----------
  81,79 +.
  
  Please advice me what could be the reasons and how do I make more than 90%.
  I have access to metalink. I raise this issue with Oracle metalink?
  
  Thank you and best regards,
  Arun Kumar

  user8853422 wrote:
  I'm afraid I can't do that... because I'm still new to DBA... What is my understanding that if buffer cache hit ratio is high, it means that server process do not need to recover data from data files, instead it will look in the buffer cache. Time is less and therefore better performance.

  Your understanding is "basically" correct.

  Please correct me if I'm wrong.

  However, your understanding is limited to a set of very specific circumstances. In reality there are times where it may be reasonable to pick up the disc.

  Basically, the concept of a specific BCHR is excellent if you have exactly the same kind of question asked time and time again (limited OLTP) ensure that guests have repeatedly looking at things in memory, or if you have enough memory to fit the entire database AND all potential read consistent blocks in the SGA.

  Anything less and you're looking at compromises.

  And that 'compromise' requirement that throws the usefulness of the BCHR whack. You need to look at the complete picture.

  Therefore, we can honestly say: If you follow your buffer Cache Hit Ratio over a period of time and your workload (transaction rate, type of transaction and competition) remains about the same, then you could grant using BCHR or use it as an indicator of the health of your system.

  But watch the BCHR and say, "this number is good" and "this number is bad" is essentially meaningless.

• Cache hit/miss ratio

  How would be know good cache size? His stats only the getNCacheMiss(), but no such thing as access to the cache.
  
  com.sleepycat.je.util.DbCacheSize is not very useful for me because I don't know what my size of data. In fact I use DPL and data size is variable.
  

• CWA advisors memory

  I have the memory following advisors of the CWA; I would like to know how to interpret these results?
  
  Notice of the PGA in memory:
  

  "PGA Target Est (MB)","Size Factr","W/A MB Processed","Estd Extra    W/A MB Read/   Written to Disk ","Estd PGA Cache Hit %","Estd PGA Overalloc Count","Estd Time"
  "138","0.99","90,700.12","11,521.57","84.00","214","788.090,200"
  "326","0.15","90,700.12","18,015.29","86.00","94","937,669,120"

  529,6 transactions per second is 476 640 transactions in 15 minutes. Links to the top with 478 498 waiting for "log file sync". There were 76 363 "log file parallel write" waits (multiple transactions validations are "grafted" in the log file entries). What is the use of the server CPU (I'm not asking about time CPU DB but CPU consumed by non-Oracle on the same server processes)?
  Each transaction is about 2 547.5 redo bytes. You have a high rate of small and moderate size of transactions which commit very frequently.

  Hemant K Collette

• cache database low hit ratio (85%)

  Hi guys,.
  
  I understand that db high cache hit ratio is no indication that the database is in good health.
  The database could be other 'physical' readings due to the listen SQL.
  
  However, can you explain why a ratio / low cache access cannot indicate that the db is unhealthy, such as db additional memory allocated?
  What I think is probably:
  
  1. the database can query various data most of the time. So the data are not yet read older seized cache. Even if I add additional memory, the data could not be read again (from memory).
  2.?
  3.
  
  I'm reluctant to list the databases below 90% as part of the monthly management report successfully. For them, less than 90% means unhealthy.
  If these reports, which will be used in the monthly report, it will be a long article to explain why these ratios can not respond but there is no worry of performance.
  
  As such need your expert advise on that.
  
  Thank you
  
  Published by: Chewy on March 13, 2012 01:23

  Hello

  You said that there is no complaint of the end-user, but that management wants to proactively scan the system. OK, monitoring proactive is a good thing, but you have to understand your system well enough to understand what to monitor. As mentioned Sybrand, if you have a system that everyone is satisfied, it does not matter what is the BCHR.

  So, what to do? Well, the answer is not simple. You must understand your system. Specifically, what are the strategic functions of your system? It doesn't matter if these are the reports that the Finance Office needs, measured in minutes or hours or response time on a special form, measured in second or subsecond response time. The point is, understand your system, what is expected and what is achievable, and then use this information to try to find contracts of service level (SLA). An SLA can read something like "90% of the executions of the sales report will daily complete in 10 minutes or less. It is important to structure the ALS in this way, "x % of executions of task that is completed in minutes of z '. If you simply say "task will be always full minutes z", you are setting yourself up for failure. All systems have variance. It's inevitable. Put between parentheses and boundaries around variance is durable and is a system that you will be able to work with.

  So, in summary:
  1.) define critical tasks.
  (2.) to characterize their performance.
  3.) working with end users and/or management define SLA contracts.
  4.) set up monitors that will measure the performance of the system and warn you if you exceed a SLA.

  Hope that helps,

  -Mark

• 'overall target of auto PGA' is too small compared to the overall target of the PGA

  Hi all.
  
  The database is 11gR 2 (11.2.0.3) on a linux machine.
  
  'global setting of target PGA' is about 25 giga size.
  'overall target of auto PGA' is about 5.5 gigabytes size
  'Allocated total PGA' is about 25 giga size.
  "total PGA inuse" is about 19.5 giga size.
  
  According to the manual of the oracle, "total target auto PGA" means:
  
  Amount of memory PGA the Oracle database can use workspaces running in automatic mode. This amount comes dynamically PGA_AGGREGATE_TARGET initialization parameter value and work load current workspace and set continuously from the Oracle database.
  
  If this value is small compared to the value of PGA_AGGREGATE_TARGET, then a large amount of memory on the PGA TOUR is used by other components of the system (for example, PL/SQL or Java memory) and little is left for work areas. The DBA should ensure that enough memory PGA is left of workspaces running in automatic mode
  
  -----------------------------------------
  
  My question is following:
  
  1. what component consumes about 20 gigabytes size of the pga (total 25 giga).
  If the PL/SQL or Java memory consumes 20 giga size, isn't too compard to a total of size pga (25giga)?
  Does rely on applications? (we have procedures/packages in the database server-side)
  
  2. the total amount allocated (25 giga) PGA is close to "Global PGA target parameter (25giga).
  "total PGA inuse" is about 19.5 giga.
  
  Is that mean that data from free space of 5.5 giga size PGA?
  I'm a bit confused between 'PGA Total allocated' and 'total PGA inuse.
  
  ------------------------------------
  
  {code}
  
  Select name, decode (unit, 'bytes', round(value/1024/1024), value) mega_value, unit
  v $ pgastat
  
  
  
  aggregate the target PGA 25 600 bytes parameter
  overall target of auto PGA 5 505 bytes
  global memory related to 1024 bytes
  Total PGA inuse 19 483 bytes
  PGA total allocated 25 503 bytes
  PGA maximum allocated 53 426 bytes
  total number of freeable memory PGA 2 486 bytes
  number of processes 5 946
  Max process count 6 039
  PGA memory freed to OS 39,677,868 bytes
  Total PGA used to auto workareas - bytes
  Maximum PGA used to auto workareas 15 543 bytes
  Total PGA used for manual workareas - bytes
  Maximum PGA used for manual workareas 38 293 bytes
  during the allocation, count 3 733
  the treated bytes 17,288,505 bytes
  3 144 169 bytes read or written additional bytes
  cache hit percentage 85%
  has count 13,254,278 (total)
  
  
  {/ code}
  
  Thanks in advance.
  
  Best regards.
  
  Published by: 869578 on October 7, 2012 20:39

  869578 wrote:
  -----------------------------------------

  My question is following:

  1. what component consumes about 20 gigabytes size of the pga (total 25 giga).
  If the PL/SQL or Java memory consumes 20 giga size, isn't too compard to a total of size pga (25giga)?
  Does rely on applications? (we have procedures/packages in the database server-side)

  The place to look is v$ process_memory (see, for example this blog post - ignore the fact that he speaks a bug 3 years ago, the SQL to query the memory usage is the bit important to you).

  2. the total amount allocated (25 giga) PGA is close to "Global PGA target parameter (25giga).
  "total PGA inuse" is about 19.5 giga.

  Is that mean that data from free space of 5.5 giga size PGA?
  I'm a bit confused between 'PGA Total allocated' and 'total PGA inuse.

  Basically Yes, your system currently thinks only about 5.5 GB of memory that can be called on any process requiring more memory to work. When a process requests from memory (for example, sorting) it will not necessarily return at the time wherever he has done with her, because she plans to use it again in the near future. This is why the amount awarded may be higher than currently in use. If another process.

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

  {code}

  Select name, decode (unit, 'bytes', round(value/1024/1024), value) mega_value, unit
  v $ pgastat

  aggregate the target PGA 25 600 bytes parameter
  overall target of auto PGA 5 505 bytes
  global memory related to 1024 bytes
  Total PGA inuse 19 483 bytes
  PGA total allocated 25 503 bytes
  PGA maximum allocated 53 426 bytes
  total number of freeable memory PGA 2 486 bytes
  number of processes 5 946

  {code}

  You have almost 6 000 live processes - and it takes a couple of MB per process just to get a few bits of SQL, is not really surprising that you have already allocated about 19 GB of memory - what is an average of 3 MB per process. You CAN see, however, that a few processes have to run away with a big piece, which is why you can watch process $ v and v$ process_memory in detail.

  Concerning
  Jonathan Lewis

• Web cache

  Hi all
  
  Alert to the EM: Critical:midtier.zihapps.ziic.net_Web Cache - 17.01 percent of the applications have access to the cache
  
  Target Name = midtier.zihapps.ziic.net_Web Cache
  Target = Cache Web type
  Host = zihapps.ziic .net
  Was held at = 19 November 2010 05:47:35 AST
  Message=17.01% queries have been cache hits
  Metric = Hits (% of applications)
  Metric value = 17.01
  Severity = critical
  Recognized = No
  Notification rule name = availability Cache Web and critical States
  Notification rule owner = SYSMAN
  
  I understand, and what I need to change the settings for this?
  
  Thank you.

  Alert to the EM: Critical:midtier.zihapps.ziic.net_Web Cache - 17.01 percent of the applications have access to the cache

  Target Name = midtier.zihapps.ziic.net_Web Cache
  Target = Cache Web type
  Host = zihapps.ziic .net
  Was held at = 19 November 2010 05:47:35 AST
  Message=17.01% queries have been cache hits
  Metric = Hits (% of applications)
  Metric value = 17.01
  Severity = critical
  Recognized = No
  Notification rule name = availability Cache Web and critical States
  Notification rule owner = SYSMAN >

  It is a Grid Control alert. You watch a 'Cache Web' through Grid Control.

  The 'Cache' midtier.zihapps.ziic.net_Web in this alert is a link. Click it and you will get to your grid control.

• Availability of Web Cache and critical States

  Hello
  
  We have recently set up the Grid control. The notification is enabled. I was more EM alert on my mail but unable to interpret it. Can someone help me in this.
  

  Target Name = EnterpriseManager0.mumsoldsoproj01.ad.crisil.com_Web Cache
  Target = Cache Web Type
  Host = mumsoldsoproj01.ad.CRISIL.com
  Metric = Hits (% of applications)
  Metric value = 16.67
  Timestamp = 15 April 2009 16:38:29
  Severity = critical
  Message=16.67% queries have been cache hits
  Notification rule name = availability Cache Web and critical States
  Notification rule owner = SYSMAN
  Notification Count = 1

  thanks

  Looks quite obvious.
  Grid control is delivered with Oracle Application Server and Oracle Application server consists among other things of Oracle Http Server and Oracle Webcache.
  Caches frequently accessed WEBCACHE URL in memory to avoid everything that the reading of the disc.
  And, Yes, Grid Control is constructed using generic components, so all traffic between Oracle Management Server and the repository database is the HTTP traffic (although WHO and the database are on the same server) so goes via Webcache.
  Grid control comes with several metrics, components different thresholds should not meet. In this cache hit of the webcache ratio is only 16.67%, which is below threshold.
  You can change the Oracle Webcache configuration using your browser and this process is obviously

  documented

  (And documents are the only thing that anyone here ever reads)

  ------
  Sybrand Bakkker
  Senior Oracle DBA

• Why the current value of the index cache is 0 MB?

  Everyone happy President's day!

  I ran calc scripts on a BSO cube. I checked EAS and data Cache hit ratio and Index is 0.

  I've already put key cache at 200 MB, but EE watch my current value hides index is 0 MB. Why?

  I already have data cache to 300 MB, but EE shows that my current value of the data cache is 0 MB. Why?

  I restarted my app BSO and db.

  Thank you.

  ORCLSendsMeToEarlyGrave wrote:

  Our test server is on Exalytics.  I wonder if this is why? All our BSO cubes have zero to Hit Ratio. Same Basic sample - after I ran Calc by default.

  If it is Exalytics that shows zero for Hit Ratio then read through a recent post that relates to this - Hit ratio

  See you soon

  John

• Question about the management of data Cache OBIEE 10g / 11g.

  Hi friends,
  
  I have a question: how we can find the display of data in the report (in the answers or dashboard) if Cache or paintings of DW? y at - there no mechanism for this? I know that normally we can find data in tables of aggregation using file view log. Can you please help on this and I would really appreciate your help.
  
  Cheers!
  Srini

  Add the suggestions above, to find the query caches

  1. use followed - cache_ind_flg O/N indicates whether or not the application has reached the cache.
  2 NQQuery.log will show "cache hit" (if not you will see SQL to the physical database)

  There is no mechanism to track if it hits the browser cache / cache of presentation server.

  I hope this helps...

• Library Cache Tuning

  HI friends,
  I m new to DBA tasks. v have oracle 11g on WIndows xp...
  
  I give me tasks to Tune Library Cache on my live server
  
  I asked rowcache $ V to get the data dictionary cache hit ratio...
  sound * 99% * (ideally the greter b at 90%)
  
  I asked librarycache $ V to get the library cache miss ratio...
  sound * 0.0006% * (ideally less than 0.1 b)
  
  I asked him too librarycache $ v to get the reord below who had problems.
  
  NAMESPACE GETS GETHITS GETHIT_RATIO PINE PINHITS PINHIT_RATIO CHARGING INVALIDATIONS
  AREA OF SQL 43586289 24169038 * 87827805 86643314 55.45* 98,65 122912 42903
  
  Usually gethit_rate should b about 70%, but its 55,45 just for the sql box?
  
  My settings shared_pool_size = 0.
  
  Can you let me know there is this... and what do I do?
  
  Thanks in adance.

  You would grant something that has proved to be a problem. Is there evidence that the library Cache Hit ratio is the performance impact?

  It may be well that the way the application refers to objects through life cycle daily is, the Cache Hit Ratio, not 'seems' to be good.

  The Cache size bookstores automatically takes the value based on the shared pool. If SHARED_POOL_SIZE is 0, then this is to be auto-resized by Oracle based on SGA_TARGET.

  Hemant K Collette