Database cache

HI all,
i read many documents about the database cache, but i still have a confusion about the
db_keep_cache_size, db_recycle_cache_size, db_nk_block_size.
kindly tell me, what is the use of this parameter, when will we use this parameter, how we assign the parameter to the database.
Regards
S.Senthil Kumar

If you really read those documents, 'kindly' explain what you don't understand, instead of just requesting to abstract those very documents.
You can read up on the difference between the parameters you mention in the Oracle reference manual easily.
Sybrand Bakker
Senior Oracle DBA

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"In-Memory Database Cache" option for Oracle 10g Enterprise Edition

Hi,
In one of our applications, we are using TimesTen 5.1.24 and Oracle 9i
databases (platform - Solaris 9i).
TimesTen holds application information which needs to be accessed quickly
and Oracle 9i is a master application database.
Now we are looking at an option of migrating from Oracle 9i to Oracle 10g
database. While exploring about Oracle 10g features, came to know about
"In-Memory Database Cache" option for Oracle Enterprise Edition. This made
me to think about using Oracle 10g Enterprise Edition with "In-Memory
Database Cache" option for our application.
Following are the advantages that I could visualize by adopting the
above-mentioned approach:
1. Data reconciliation between Oracle and TimesTen is not required (i.e.
data can be maintained only in Oracle tables and for caching "In-Memory
Database Cache" can be used)
2. Data maintenance is easy and gives one view access to data
I have following queries regarding the above-mentioned solution:
1. What is the difference between "TimesTen In-Memory Database" and
"In-Memory Database Cache" in terms of features and licensing model?
2. Is "In-Memory Database Cache" option integrated with Oracle 10g
installable or a separate installable (i.e. TimesTen installable with only
cache feature)?
3. Is "In-Memory Database Cache" option same as that of "TimesTen Cache
Connect to Oracle" option in TimesTen In-Memory Database?
4. After integrating "In-Memory Database Cache" option with Oracle 10g, data
access will happen only through Oracle sqlplus or OCI calls. Am I right here
in making this statement?
5. Is it possible to cache the result set of a join query in "In-Memory
Database Cache"?
In "Options and Packs" chapter in Oracle documentation
(http://download.oracle.com/docs/cd/B19306_01/license.102/b14199/options.htm
#CIHJJBGA), I encountered the following statement:
"For the purposes of licensing Oracle In-Memory Database Cache, only the
processors on which the TimesTen In-Memory Database component of the
In-Memory Database Cache software is installed and/or running are counted
for the purpose of determining the number of licenses required."
We have servers with the following configuration. Is there a way to get the
count of processors on which the Cache software could be installed and/or
running? Please assist.
Production box with 12 core 2 duo processors (24 cores)
Pre-production box with 8 core 2 duo processors (16 cores)
Development and test box with 2 single chip processors
Development and test box with 4 single chip processors
Development and test box with 6 single chip processors
Thanks & Regards,
Vijay

Hi Vijay,
regarding your questions:
1. What is the difference between "TimesTen In-Memory Database" and
"In-Memory Database Cache" in terms of features and licensing model?
==> Product has just been renamed and integrated better with the Oracle database - Times-Ten == In-Memory-Cache-Database
2. Is "In-Memory Database Cache" option integrated with Oracle 10g
installable or a separate installable (i.e. TimesTen installable with only
cache feature)?
==> Seperate Installation
3. Is "In-Memory Database Cache" option same as that of "TimesTen Cache
Connect to Oracle" option in TimesTen In-Memory Database?
==> Please have a look here: http://www.oracle.com/technology/products/timesten/quickstart/cc_qs_index.html
This explains the differences.
4. After integrating "In-Memory Database Cache" option with Oracle 10g, data
access will happen only through Oracle sqlplus or OCI calls. Am I right here
in making this statement?
==> Please see above mentioned papers
5. Is it possible to cache the result set of a join query in "In-Memory
Database Cache"?
==> Again ... ;-)
Kind regards
Mike

SQL Result Cache vs In-Memory Database Cache

Hi,
can anyone help me to understand the relations and differences between the 11 g new features of SQL Result Cache vs In-Memory Database Cache ?
Thanks

I highly recommend you read the 11g New Features Guide. Here is a sample from it:
h4. 1.11.2.9 Query Result Cache
A separate shared memory pool is now used for storing and retrieving
cached results. Query retrieval from the query result cache is faster
than rerunning the query. Frequently executed queries will see
performance improvements when using the query result cache.
The new query result cache enables explicit caching of results in
database memory. Subsequent queries using the cached results will
experience significant performance improvements.
See Also:
[Oracle Database Performance Tuning Guide|http://download.oracle.com/docs/cd/B28359_01/server.111/b28274/memory.htm#PFGRF10121] for details
[Results Cache Concepts|http://download.oracle.com/docs/cd/B28359_01/server.111/b28274/memory.htm#PFGRF10121|Results Cache Concepts]
HTH!

Database Cache and Gateways

We are considering using Oracle Database Cache to speed up a web application that reads data from a mainframe database. Since Database Cache only works with Oracle databases, we plan to create a new Oracle database that acts as a gateway (using ODBC) to the mainframe.
The question we have is whether this would be possible and would make sense from a performance perspective. It is possible that Database Cache makes clever use of Oracle metadata (table update timestamps, etc) which would not be available for tables linked through ODBC. In this case, Database Cache might not work properly.
Is it possible to configure Database Cache in such a way that that the application reads data from the mainframe only when the data in the cache is more than an hour old?

moving up...
Hi
I have a question regarding the 9iAS database cache: when I
select a table to be cached, does the cache also pull up the
indexes definition from the origin database? Another way to put
it: if I cache a table which has an index on the PK ( on the
origin database ), is the index also created on the db cache or
it performs a full scan for every query?
Thanks
Ramiro

Oracle TimesTen In-Memory Database VS Oracle In-Memory Database Cache

Hi,
What is difference in Oracle TimesTen In-Memory Database VS Oracle In-Memory Database Cache.
For 32 bit on windows OS i am not able to insert data's more than 500k rows with 150 columns (with combinations of CHAR,BINARY_DOUBLE,BINARY_FLOAT, TT_BIGINT,REAL,DECIMAL,NUMERIC etc).
[TimesTen][TimesTen 11.2.2.2.0 ODBC Driver][TimesTen]TT0802: Database permanent space exhausted -- file "blk.c", lineno 3450, procedure "sbBlkAlloc"
I have set Perm size as 700 mb,Temp size as 100mb
What is the max size we can given for PermSize,TempSize,LogBufMB for 32 bit on windows OS.
What is the max size we can given for PermSize,TempSize,LogBufMB for 64 bit on windows OS.
What is the Max configuration of TT for 32 bit what i can set for Perm size Temp size.
Thanks!

They are the same product but they are licensed differently and the license limits what functionality you can use.
TimesTen In-Memory Database is a product in its own right allows you to use TimesTen as a standalone database and also allows replication.
IMDB Cache is an Oracle DB Enterprise Edition option (i.e. it can only be licensed as an option to an Oracle DB EE license). This includes all the functionality of TImesTen In-Memory Database but adds in cache functionality (cache groups, cache grid etc.).
32-bit O/S are in general a poor platform to try and create an in-memory database of any significant size (32-bit O/S are very limited in memory addressing capability) and 32-bit Windows is the worst example. The hard coded limit for total datastore size on 32-bit O/S is 2 GB but in reality you probably can;'t achieve that. On Windows the largest you can get is 1.1 GB and most often less than that. If you need something more than about 0.5 Gb on Windows then you really need to use 64-bit Windows and 64-bit TimesTen. There are no hard coded upper limit to database size on 64-bit TimesTen; the limit is the amount of free physical memory (not virtual memory) in the machine. I have easily created a 12 GB database on a Win64 machine with 16 GB RAM. On 64-bit Unix machines we have live database of over 1 TB...
Chris

Using In-Memory Database Cache option need help

Hi,
I need some help:
I am using Oracle 10g Server Release 2
For Clientele activilty I am using Oracle Client where the Application resides.
For Better performance I want to use the In-Memory Database Cache option Times-Ten Database.
Is it possible to do so where there is Oracle Database Server Relaease 2 and in the Client there is Times-Ten In-Memory Database Cache?
Any help will be needful for me

In-Memory Cache is a server-side cache. I can not see where there would be any value putting it on the client side though given the license cost per CPU core I am sure the entire Oracle sales force would gladly disagree with me.

Oracle 9iAS Database cache

Hi
We are using Oracle 9iAS 9.0.3.
I am interested to confirm if the Database Cache technology supplied with previous versions of Oracle 9iAS app server has been phased out. Does Oracle 9iAS 9.0.3 support it?
Waiting for a quick reply.
Thanks All
nitin

kishore, I don't see any problem installing iAS on two different machines, if that's what you mean. Whatever you install on the 'second' machine will not affect the first. Since they have the different oraInventory location.

Forms/Reports: Role of the Database cache and Web cache

Hello oracle experts,
I am running a purely Forms and Reports based environment (9iAS).
My question are:
a. Is it possible to use features from the Web Cache and
Database Cache to boost the performance of my applications?
b. Are all components monitorable from the OEM?
Please guide me so that i can configure my OEM to monitor my
forms and reports services.
thanks in advance for your reply
Kind regards
Yogeeraj

Hi BradW,
The way this is supposed to be done in Web Cache is by keeping separate copies of a cached page for different types of browsers distinguished by User-Agent header.
In case of cache miss, Web Cache expects origin servers to return appropriate version of the page based on browser type, and the page from the origin server is just forwarded back to browser.
Here, if the page is cacheable, Web Cache retains a separate copy for each type of User-Agent header value.
And when there is a hit on this cached page, Web Cache returns the version of page with the User-Agent header that matches the request.
Check out the config screen titled "Header Association" for this feature.
About forwarding requests to different origin servers based on User-Agent header value, Web Cache does not have such capability.

Oracle In-Memory Database Cache

Hi,
I was reading about Oracle in Memory database cache and i am wondering is this option available on 10g, from what i read it is only on 11g and it is extra option and have to pay for it.
Any more info, will be great.
thanks

From here
The In-Memory Database Cache option of Oracle Database Enterprise Edition is based on Oracle TimesTen In-Memory Database.TimesTen is also available for 10g.

Oracle In-Memory Database Cache Testcases

We are implementing Oracle In-Memory Database Cache on an existing oracle database. We want to do some extensive testing on Oracle In-Memory Database. Can anybody please share some pointers in writing testcases ?

Best place to start is here:
http://www.oracle.com/technetwork/products/timesten/overview/index.html
In particular take a look at the Quickstart which is provided as part of the install of the product and can be accessed online here http://www.oracle.com/technetwork/products/timesten/learnmore/index.html via http://download.oracle.com/otn_hosted_doc/timesten/1122/quickstart/html/main/home.html
Take a look at the sample programs the tptbm program is a good place to start.
Tim

Error in configuring database cache

Dear friends,
I installed Oracle 9ias on the original oracle 9i database on the same machine. When I configured database
database cache. The followings error message appeared when I use wtacce -create -typical:
ORA-01034: Oracle not available
ORA-27101: share memory realm doesn't exist
SVR4 error: no such file or directory.
How can I fix them?
Thank you in advance

Database Cache is being phased out in 9iAS release 2. Please post all Database Cache questions on the general database discussion forum.

Database cache (old wine in new bottle???)

Hello!
today to my shock I realised that
the entire Database cache is indeed
based on REPLICATION!
Can someone please confirm to me
(rather allay my fears) regarding
performance, before I go live?
Thanks
Further can someone please answer my
following doubts:
Can icache database be used as a
standby(?) in case the origin database crashes?
My application uses forms/reports/mod_plsql
can I exploit Database cache?
Can I have 2 distinct cache databases
on one node, have 2 distinct origin databases?
Thanks a lot

Replication plus Net8 library little rewriting (little trick :). This library is modified only in iAS distribution. To use this functionality you must set ORA_OCI_CACHE environment variable, but you can not put it in the Registry :)
iCache can be used as a 'standby' without update availability and you MUST connect directly to iCache database.
Yes, you can
You can not have 2 distinct iCache databases on the same node.
You can have 2 distinct origin databases and one iCache on the same node, but iCache can be bound only to one of them.
null

Database Cache config failed when 26%

My scene is:
oracle db 8.1.7 on Solorias 8
database cache of iAs9i on another Solorias 8
the error detail is:
Configuring the cache
Creating the cache
Starting up the cache
Setting up the Cache Listener
Connecting to the Cache
Connecting to the Cache failed
Reason:ORA-01034:Oracle not available
ORA-27101:shared memory realm dose not exist
SVR4 Error:2:No such file or directory
Any one and any help
thanks!
null

Hi,
I got the similar error when I installed 8i iAS. The error is
Updating User List
Adding users to the cache
Adding users to the cache failed.
Reason: WTE-03501 Error updating list of users: Export failed on origin database.
OCI error - ORA-06520: PL/SQL: Error loading external library
ORA-06522: dlopen: cannot load /lib/libc.so
ORA-06512: at "SYS.WTCSYS", line 11
ORA-06512: at "SYS.WTCSYS", line 66
ORA-06512: at line 1
My original DB is installed in TRU64 Unix. I copied the libc.so file in the /lib directory of the UNIX server. Copied the file from the /usr/shlib/libc.so to the /lib directory.
This solved my problem. Hope this information will be helful to you
Regards,
Srikanthan S

Database Cache Hit ratio is very less

Hi All,
my live database Cache Hit ratio is very less. can some one proposed relevant solution for that.
SELECT (1-((phy.value-phyd.value) / (cur.value + con.value))) * 100 "Cache Hit ratio"
FROM v$sysstat cur, v$sysstat con, v$sysstat phy, v$sysstat phyd
WHERE cur.name = 'db block gets'
AND con.name = 'consistent gets'
AND phy.name = 'physical reads'
AND phyd.name = 'physical reads direct';
Cache Hit ratio
47.99717699362490769958384625413175240442
select NAME,VALUE from v$parameter where name like '%db_cache_size%';
NAME VALUE
db_cache_size 335544320
select name, value From v$sysstat
where name in ('db block gets', 'consistent gets', 'physical reads');
NAME VALUE
db block gets 30047032214
consistent gets 691770165681
physical reads 376120181932
Thanks

user1093072 wrote:
Hi all thanks a lot for your answers. i am getting some query time outs and while investigating got less ratios. can some one tell me how to get dicission using this ratios
Buffer Hit % 95.71
Cache Hit ratio 47.99The fact that you get two different values for "the same thing" is a clue that (a) your SQL statement is suspect and (b) your logic is flawed.
You SQL is going to give you some kind of (meaningless) average since the database started up. The report you showed looks like part of an AWR or statspack report which will be covering a short interval of time. The difference between the two percentages may mean the two approaches are using different formula, or it may mean that the result is highly dependent on the time window.
Since you have access to AWR/statspack - run off a report for a (short) interval when the system is performing well, and for when the system is performing badly, and compare them.
As a starting point you could post the two sections "Load Profile" and "Top 5 Timed Events" to the forum for initial comment. If you do so, please make sure you use the "code" tags (see end of post) to make the output readable or you may get no replies.
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
http://www.jlcomp.demon.co.uk
To post code, statspack/AWR report, execution plans or trace files, start and end the section with the tag {noformat}{noformat} (lowercase, curly brackets, no spaces) so that the text appears in fixed format.
There is a +"Preview"+ tab at the top of the text entry panel. Use this to check what your message will look like before you post the message. If it looks a complete mess you're unlikely to get a response. (Click on the +"Plain text"+ tab if you want to edit the text to tidy it up.)

Database cache settings for 4.13 on NT 4

The database cache settings and the documentation have always been
confusing.
I have about 35000 entries in my directory. If I have enough available ram
should I try to put all the entries into ram? The default setting is a 1000,
should I change it to 35000? Will I notice any great speed increases.
And the second setting has to do with index cache. Should I try to get that
into ram also? My id2entry.db2 file is about 40MBs. Should I change the
default from 10MBs to 40MBs? Will there be a significant increase in speed?
Thanks.

Thanks Russ H for your quick reply. I am still fairly new to FCP X coming from using FCE not iMovie.
The project I'm working on I had already started before posting yesterday. Is it possible to change the settings for what I have already done, or no I need to start all over again?
Thanks again
Matt

Database cache

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