Hit Ratio in the data Caches

Similar Questions

• Current value of the data cache 0

  Hi all

  The database I have is responsible, however, the CURRENT VALUE of the DATA CACHE, CURRENT VALUE of the INDEX CACHE, etc. show all 0.

  What could be the reason why it shows 0?

  He must have some numbers right?

  Thank you

  Is there a schema and data in the cube?

  I'm a little surprised by the index cache data cache may not be transferable by any space until you do really something with the data of the cube (extract, load, calculate, etc.) but key cache seems to be filled immediately.

• How to interpret the data cache setting and the current value of data cache?

  How to interpret the data cache setting and the current value of data cache? We found that even, we configure a larger data cache in Essbase 2 GB for example, the current value of the data cache is always much lower. Does that indicate an activities of data at very low recovery or something else?
  
  Thanks in advance!

  Hello

  When a block is requested, Essbase searches the data for the block cache. If Essbase is the block in the cache, it is immediately accessible. If the block is not found in the cache, Essbase in the index for the appropriate block number and then uses the index of the block entry to retrieve from the data on the disk file. Retrieve a block requested in the data cache is faster and therefore improves performance.

  So as you say that its current value is much lower then % is very low, that a requested block is in the cache of Essbase data.

  Hope that respond you to the.

  Atul K

• I have to stop and start the database after the data cache value increases?

  Hello!

  rule of Calc is in error and indicating that the error can be caused by data cache setting small size?

  I increased the value, but it still gives the same error message. I can't stop and start the database, just clicked on apply.

  I need also to check the journal rule and computation of the application to determine the cause of the error.

  But the key is in the question in the header...

  Kind regards

  user637777

  
  

  Yes, you do.

• Data to the maximum cache

  I change the settings in the data cache, the high value (4194303) and still get the error 1006023. What happens to my database? Sorry for my English.

  The size of your account should be very dense. It is a very high data cache parameter, you don't need to put aside that much space especially if you use some simple calculations. Try to reduce the data cache approximately 50,000 and see if you still get the same error code.

• 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

• Size of data Cache is full

  Dear,

  I am facing a problem with the data cache. I increased the data cache. but it seems that there's something wrong with my business rule. In accordance with the following:

  
  

  If you keep increasing the cache, but you still have this issue, it's time for you to think about your business rule or your design. Because more memory you allocate for the data cache, the more essbase RAM will succeed permanently (never released even the rule has already finished) unless you restart the app/Essbase cube

  My question : is there away to restart the app/Essbase cube without restarting the Essbase Server?  It makes no sense that whenever I have test the business rule, I need to do a reboot of the essbase server, if it does not work properly.

  Thank you in advance!

  Yes power of the database in environmental assessments, in Maxl look alter application and unloading/loading of database statements.

  See you soon

  John

  http://John-Goodwin.blogspot.com/

• hiding playback, ho multiple copies of the data?

  I'm trying to understand the functioning of the readings for a virtual machine that is reflected through 2 different ESXi:

  On VMware Virtual SAN 6.0 pdf design and Sizing Guide, I read:

  When there are multiple replicas of the Virtual SAN divided up to the caching of the data uniformly blocks between copies of the replica.

  In an another blog post, I read:

  VSAN always try to make sure he sends a reading given to the same replica so that the block gets put in cache only once in the cluster

  I understand that the 2 sentences are so... now very different, I do not understand how the placement of the data cached reading really. works.

  How does the read cache?

  An example of TFT = 1.

  In this case, there are two copies of the data.

  Based on the offset we read on the VMDK, we will that is read from the first VMDK/copy data, or the second copy/VMDK data.

  This block is then cached in the matte layer on the same disk group as we read the block.

  So each block is cached only once, in the disk group where the block is read and not cached in two disk groups.

  You can extrapolate this output for FTT = 2 and FTT = 3.

  HTH

  Cormac

• It is possible to disable the global cache in the CCR?

  Hello
  I'm in a rac 11.2 database.
  I have a lot of racing only on node 1.
  It is possible to disable the events of the gc? I have no need that blocks are passed to another istances.
  
  Thank you

  user12288492 wrote:
  If you want to disable the moving blocks from one instance to another, you can use application partitioning that is access the blocks from a single instance. If no other instance asks of these blocks will not be moved multiple instances.

  Please, there is no this: + "disable the moving blocks from one instance to another." + "

  Number 1 of the notion on env RAC:

  To make sure that each Oracle RAC database instance Gets the block she needs to satisfy a query or transaction, Oracle RAC instances use two processes, the Service of world (SCM) and Cache the queue Service Global (GHG). The GCS and GES maintain records on the statutes of each data file and each cached block using a directory of resources Global (GRD). The GRD content is distributed in all active instances, which increases the size of the SGA of an Oracle RAC instance.

  After one instance implements the data cache, no other instance in the same cluster database can acquire an image of block of another instance in the same database faster than by the block of the disc. So, Cache Fusion moves current blocks between instances rather than read the blocks from disk. When a consistent block is necessary or a modified block is run on another instance, Cache Fusion transfers the image block directly between the authorities concerned. Uses Oracle RAC private interconnection for transfer of communication and block interinstance. The monitor of GHG and Instance Enqueue process manage access to resources of Cache Fusion and transformation of recovery enqueue.

  It is not possible to ensure that the specific blocks will be only on specific nodes, unless you have only one active instance. The blocks will be COPIED (not moved) from one node to another when they are requested.
  There is no way to control this... as far as I know.

  If someone has problems with the events of the GC, you should analyze and use the "My Oracle Support" for your problem. Please don't think that something like the disabling of the GC, because it's madness.

• 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

• 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.

• Quality of the data buffer Cache

  Hi all
  
  Can someone please please tell some ways in which I can improve the quality of data buffer? He is currently at 51.2%. The DB is 10.2.0.2.0
  
  I want to know all the factors of wat should I keep in mind if I want to increase DB_CACHE_SIZE?
  
  Also, I want to know how I can find Cache Hit ratio?
  
  In addition, I want to know which are the most frequently viewed items in my DB?
  
  Thank you and best regards,
  
  Nick.

  Bolle wrote:
  You can try to reduce the size of the buffer cache to increase hit ratio.

  Huh? It's new! How would it happen?
  Aman...

• 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...

• is 10g - possible to know if the report to get the data in the CACHE?

  Hi, experts,
  
  Is it possible to know if the report to get the data in the CACHE (per share on the dashboard page)?
  
  of NQQuery.log?

  Forreging,

  Yes, it is possible to know if a query pulled from the cache to access Oracle answers/dashboards or not.
  If you find the part of the sentence "cache hit on request" within the NQQuery.log against any request, this request did get the results from the cache.

  Another way:
  Also under settings > Administration > manage Sessions if you find "Ref" > 1, which refers the number of times where a cache is used to provide results.

  -bifacts :-)
  http://www.obinotes.com

  Published by: bifacts on November 1st, 2010 22:42