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1 reply Latest Post - ‏2013-03-13T21:57:40Z by KaranBal
SystemAdmin
SystemAdmin
648 Posts
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Pinned topic Performance Info Caches Catalog

‏2013-02-22T10:16:29Z |
Look at System Administrator->Perfomance Info->Caches.
Why would the Catalog hit ratio be low?
All the other ratios are nice and high.

What would it achieve if it was increased.
We have two massive catalogs and do not really have within them many items that would be accessed more frequently than others.

We sometimes get in appsvr db.log
CWPCM0018W:The query is delayed

I have looked at:
https://www.ibm.com/developerworks/forums/thread.jspa?messageID=14639719&#14639719
Updated on 2013-03-13T21:57:40Z at 2013-03-13T21:57:40Z by KaranBal
  • KaranBal
    KaranBal
    108 Posts
    ACCEPTED ANSWER

    Re: Performance Info Caches Catalog

    ‏2013-03-13T21:57:40Z  in response to SystemAdmin
    About cache hit ratio:
    Low cache hit ratio means poor performance for the end users. Basically all computer programs use memory(RAM) to save frequently accessed data and they get the rest of the data from the database. Getting information from the database is very slow for obviously reasons and getting it through memory is fast. So if your cache hit ratio is low, then that means your system is fetching information from the database frequently causing slowness. That will also explain the slow queries. Better hit ratio can not prevent slow queries but they will lower the number.
    Why is it low:
    In the $TOP/etc/default, there are 2 files mdm-cache-config.properties and mdm-ehcache-config.xml which basically tell the system how many objects like items and specs to keep in memory. If you have a lot of memory but the application is configured to save few objects, then your hit ratio will be low. It is recommended to have atleast 90% hit ratio. To do so, increase the number of elements in these files.