Tuning filesystem cache usage to benefit Oracle db workloads

We have several OEL 6 servers running Oracle 11g workloads. Typical output from a "free" command on a system with 8 Gig RAM shows 5 to 6 Gig cache usage.
Are there VMM tuning parameters that can be set to bias the system to use less filesystem cache?
In EL 5 and earlier there was a kernel tunable called vm.pagecache that I believe was used to tune cache behavior, but it is not present in OEL 6.
Thanks

IBM provides excellent documentation.
Unfortunately, to find such information for Linux requires to get bits and pieces from here or there. The available documentation has often too much room for interpretation if you already have a technical background, or is too detailed, making it difficult to comprehend. However, I guess the problem pretty much applies to all products developed during the last decade.
I have honestly no experience with AIX. My experience with commercial Unix systems is limited to Tru64, which is all RIP now. IT is a strange business, often favoring trivial over more superior solutions, eventually coming around in the end. Linux has certainly come a long way. However, it is under constant development and can implement drastic changes, for instance, raw disk support.
By the way, OEL was renamed to Oracle Linux. OL uses the Oracle UEK kernel by default, which is optimized for Oracle products. Product patches and errata can be downloaded for free from Oracle Public Yum. To simplify the initial installation, you can install the "oracle-rdbms-server-11gR2-preinstall" package. It does the setup of kernel parameters, oracle groups and accounts, and triggers the installation of prerequisite software for Oracle DB installation.
For performance reasons, you might want to setup the system to use kernel hugepages, which is apparently the number 1 performance issue related to Oracle under Linux. Hugepages are a significant drop in server resource utilization for memory and processing. The following links should be helpful:
/dev/shm on Oracle Linux 6.x to run Oracle 11g R2 - manual configuration?
Re: Understanding kernel hugepages and Oracle 11g AMM compatibility

Similar Messages

Buffer Cache Usage

How can I calculate current buffer cache usage?

Hi;
What is Db version?
Pelase see:
http://blog.lishman.com/2008/05/oracle-quick-tip-querying-buffer-cache.html
Also see below googling which is mention your question's answer
http://www.google.com.tr/#hl=tr&source=hp&q=buffer+cache+usage%3F+&oq=buffer+cache+usage%3F+&aq=f&aqi=&aql=&gs_sm=e&gs_upl=0l0l0l250l0l0l0l0l0l0l0l0ll0&fp=503f556dbe78c402&biw=1280&bih=797
Regard
Helios

High cache usage of free memory

I dont know if this is normal but my fresh archlinux x86_64 install with Xfce uses round 300Mb of 4Gb ram space after boot but then after i start and close some programs i get to 3 Gb used of 3.87 Gb free memory when all applycation are closed. Now i understand that kernel caches some data in memory but i cant clear it all with commands:
sync
echo 1 > /proc/sys/vm/drop_caches
echo 2 > /proc/sys/vm/drop_caches
echo 3 > /proc/sys/vm/drop_caches
After i do that system reports 540 Mb used compared to 300Mb from boot. Is there a way to limit the ammount of cache usage so i dont end up having all free memory used by cache?
Last edited by Anril (2009-12-29 13:19:52)

Ram that is unused is wasted ram, the linux kernel manages it very well so no worries there.
If you have swap usage it's because most probably you have things stored in the ram that are not being used often but cannot be discarded too so things being used more often take precedence.
If you think you have enough ram for all your needs then why not disable swap? I've read that there might be a speed penalty for running without swap but I've been running my system without swap (arch64 4G ram) and I've never had any bad surprises.
There are a few things that might prompt swap usage (don't quote me on that though, it just seems to me to be the case), if you copy many files from one place to the other the kernel will use all the ram available to try to cache them, if you copy many GB then all the ram will get filled (and maybe other things will get evicted to swap).
It's not a bug, free ram is there to be used, things that have been used/needed recently get to stay in the ram, other things can go to the swap, if you can cache a file that has been recently used and need to use it again shortly after then it's much faster if it is in the ram instead of having to read it again from the hard disk. The logic behind it is good, it's just that some corner cases may make behave badly.

Data Cache usage 96%

Hi Experts,
With total 7 planning versions and total size of 9GB, the data cache is constantly filling up
Total 14GB allocated and each time we create a new version the usage goes up by 10%.
There are no old sessions more than 4 hrs and when 5 planners starts working simutaneously, the cache starts filling up
Thanks,
Naren

> With total 7 planning versions and total size of 9GB, the data cache is constantly filling up
>
> Total 14GB allocated and each time we create a new version the usage goes up by 10%.
>
> There are no old sessions more than 4 hrs and when 5 planners starts working simutaneously, the cache starts filling up
Now what?
You create multiple versions of liveCache objects in parallel - of course the cache usage will increase (and also the used space in the data area).
That's how the multi-version-data-handling works.
A copy of the current version is created for each new version.
So either add more cache, reduce your planning version complexity/size or do less in parallel if you want to prevent the cache from beeing used 100%.
regards,
Lars

Livecache data cache usage - table monitor_caches

Hi Team,
We have a requirement of capturing the Data cache usage of Livecache on an hourly basis.
Instead of doing it manually by going into LC10 and copying the data into an excel, is there a table which captures this data on a periodic basis which we can use to get the report at a single shot.
"monitor_caches" is one table which holds this data, but we are not sure how we can get the data from this table. Also, we need to see the contents of this table, we are not sure how we can do that.
As "monitor_caches" is a maxdb table I am not sure how I can the data from this table. I have never worked on Maxdb before.
Has anyone had this requirement.
Warm Regards,
Venu

Hi,
For Cache usage below tables can be referred
Data Cache Usage - total (table MONITOR_CACHES)
Data Cache Usage - OMS Data (table MONITOR_CACHES)
Data Cache Usage - SQL Data (table MONITOR_CACHES)
Data Cache Usage - History/Undo (table MONITOR_CACHES)
Data Cache Usage - OMS History (table MONITOR_CACHES)
Data Cache Usage - OMS Rollback (table MONITOR_CACHES)
Out Of Memory Exceptions (table SYSDBA.MONITOR_OMS)
OMS Terminations (table SYSDBA.MONITOR_OMS)
Heap Usage (table OMS_HEAP_STATISTICS)
Heap Usage in KB (table OMS_HEAP_STATISTICS)
Maximum Heap Usage in KB (table ALLOCATORSTATISTICS)
System Heap in KB (table ALLOCATORSTATISTICS)
Parameter OMS_HEAP_LIMIT (KB) (dbmrfc command param_getvalue OMS_HEAP_LIMIT)
For reporting purpose , look into the following BW extractors and develop BW report.
/SAPAPO/BWEXDSRC APO -> BW: Data Source - Extractor
/SAPAPO/BWEXTRAC APO -> BW: Extractors for Transactional Data
/SAPAPO/BWEXTRFM APO -> BW: Formula to Calculate a Key Figure
/SAPAPO/BWEXTRIN APO -> BW: Dependent Extractors
/SAPAPO/BWEXTRMP APO -> BW: Mapping Extractor Structure Field
Hope this helps.
Regards,
Deepak Kori

Performance tuning for siebel CRM application on oracle database

Hi,
Please send me the link for Performance tuning for siebel CRM application on oracle database. If there are any white papers please send me the link.
Thanks,
Rajesh

Hi,
This metalink document is very useful, if you have any other documents or links please inform me.
Thanks once again
Rajesh

Are Tuning pack, Diagnostics pack available on Oracle 9i?

hi,
Tuning pack, Diagnostics pack are available on oracle 9i?
If yes, how can I set it?
thanks & regards,

You are confusing one for the other. You have probably heard of AWR requiring the Diagnostics Pack and wonder what the pack can do in 9i if AWR is not available in 9i.
Usage of AWR and related features available from 10g requires the Diagnostics Pack. However, usage of the SQL Advisors requires the Tuning Pack.
The two are separate packs. These are products from the Oracle Enterprise Manager stack.
Tuning Pack and Diagnostics Packs have been available in 8i as well.
So, you can purchase these packs in 8i, 9i, 10g, 11g . If you have purchased them and paid annual support fees, you can upgrade them.
What you can do with the packs may well vary in each version. Thus, AWR is not available in 9i and below.
8i : http://download.oracle.com/docs/cd/A87860_01/doc/em.817/a85250/ch5.htm#1007872
9i : http://download.oracle.com/docs/cd/B10501_01/em.920/a96674/packs.htm#1015821
Since 10g, Oracle also includes a Licencing Guide in the documentation set.
See http://download.oracle.com/docs/cd/B19306_01/license.102/b14199/options.htm#CIHGFIAF
and http://download.oracle.com/docs/cd/B19306_01/license.102/b40010/toc.htm
Hemant K Chitale

Query tuning for data-warehousing application in Oracle 8i.

We have to pick up 24 months old data. Each month data is kept in a different partition.
2007-May month data is kept in PRESC200705 partition
SELECT r.account_id,
p.presc_num,
spm.product_id,
p.month,
t.best_call_state,
sum(p.trx_count)
FROM rlup_assigned_account r,
temp_presc_num_TEST t,
retail.prescrip_retail partition (PRESC200705) p,
sherlock.sherlock_product_mapping spm
WHERE spm.product_id like '056%'
and spm.mds6 = p.product_id
and t.CLIENT_ID = p.presc_num
and r.ndc_pyr_id = p.payer_plan
and t.best_call_state = r.ST
GROUP BY r.account_id,
p.presc_num,
spm.product_id,
p.month,
t.best_call_state
Q This Query is to be tuned
SQL> SELECT table_name,
2 partition_name,
3 high_value,
4 num_rows
5 FROM user_tab_partitions
6 ;
no rows selected

I have the following task:
Requirement:
According to the client, new partitions are created every month.
So the query should contain only the 24 most recent partions leaving one old partition every month.
So, the query becomes dynamic.
The query will have to leave one old partion every month and move ahead with the new partion created.
The total partitions accessed should not cross 24.
Is this possible?
Partition# for OCt 2007
1
2
3
4
5
6
7
24
Partition# for Nov 2007
Old|New
1
2..1
3..2
4..3
5..4
6..5
7..6
24..23
..24
Secondly, with one month data (in a partitioned table), the query takes about one hour to run.
with 24 month data accessed by the query, the query will take 24 hours to run.
I am sure that Oracle can be tuned to run on such huge data with ease and the query output can
come within seconds.. Otherwise, nobody would use oracle for datawarehousing applicaions.
Q. How do I write a dynamic query that references 24 recent partitions, using the query provided:
abc>SELECT r.account_id,
2 p.presc_num,
3 spm.product_id,
4 p.month,
5 t.best_call_state,
6 sum(p.trx_count)
7 FROM rlup_assigned_account r,
8 temp_presc_num_TEST t,
9 retail.prescrip_retail partition (PRESC200705) p,
10 sherlock.sherlock_product_mapping spm
11 WHERE spm.product_id like '056%'
12 and t.CLIENT_ID='934759'
13 and spm.mds6 = p.product_id
14 and t.CLIENT_ID = p.presc_num
15 and r.ndc_pyr_id = p.payer_plan
16 and t.best_call_state = r.ST
17 GROUP BY r.account_id,
18 p.presc_num,
19 spm.product_id,
20 p.month,
21 t.best_call_state
22 ;
retail.prescrip_retail partition (PRESC200705) p,
Partition name, PRESC200705 cannot be hardcoded into the sql.
Sql should take a range of 24 recent partitions.
And the query should execute fast too.
Now, is that what is called a challenge?
+++++++++++++++++++++++++++++++++++++++++++++++
Here are the index/constraints/explain_plan output on prescrip_retail table (which is partitioned)
as well as other tables to which prescrip_retail table is joined
This is what prescrip_retail looks like. This is the table having partitions.
It does not seem to have a primary key!
SQL> desc prescrip_retail
Name Null? Type
PRESC_NUM NUMBER
PFIER_NUM CHAR(8)
RELID NOT NULL CHAR(9)
ME_NUM NOT NULL CHAR(10)
PRODUCT_ID NOT NULL CHAR(6)
PRODUCT_FRMSTR NOT NULL CHAR(1)
PAYER_PLAN NOT NULL CHAR(6)
MONTH NOT NULL DATE
PYMT_CODE NOT NULL CHAR(1)
NRX_COUNT NOT NULL NUMBER(7)
NRX_QUANTITY NOT NULL NUMBER(9)
NRX_DOLLARS NOT NULL NUMBER(13,2)
TRX_COUNT NOT NULL NUMBER(7)
TRX_QUANTITY NOT NULL NUMBER(9)
TRX_DOLLARS NOT NULL NUMBER(13,2)
Table Size of Prescrip_Retail...
1 select table_name,tablespace_name,pct_free,pct_used,num_rows,avg_space
2 from all_tables
3* where table_name='PRESCRIP_RETAIL'
SQL> /
TABLE_NAME TABLESPACE_NAME PCT_FREE PCT_USED NUM_ROWS AVG_SPACE
PRESCRIP_RETAIL 2806673860 360
Explain Plan for the query to be tuned...
22:32:31 SQL> explain plan set statement_id='vista_query'
22:43:33 2 for
22:43:35 3 SELECT r.pfier_account_id,
22:43:41 4 p.presc_num,
22:43:41 5 spm.product_id,
22:43:41 6 p.month,
22:43:41 7 t.best_call_state,
22:43:41 8 sum(p.trx_count)
22:43:41 9 FROM rlup_assigned_account r,
22:43:41 10 temp_presc_num_TEST t,
22:43:41 11 retail.prescrip_retail partition (PRESC200705) p,
22:43:41 12 sherlock.sherlock_product_mapping spm
22:43:41 13 WHERE spm.product_id like '056%'
22:43:41 14 and spm.mds6 = p.product_id
22:43:41 15 and t.CLIENT_ID = p.presc_num
22:43:41 16 and r.ndc_pyr_id = p.payer_plan
22:43:41 17 and t.best_call_state = r.ST
22:43:41 18 GROUP BY r.pfier_account_id,
22:43:41 19 p.presc_num,
22:43:41 20 spm.product_id,
22:43:41 21 p.month,
22:43:41 22 t.best_call_state;
Explained.
SQL> select statement_id,operation,options,object_name
2 from plan_table
3 where statement_id='vista_query';
22:46:03 SQL> /
STATEMENT_ID OPERATION OPTIONS OBJECT_NAME
vista_query SELECT STATEMENT
vista_query SORT GROUP BY
vista_query HASH JOIN
vista_query TABLE ACCESS FULL TEMP_PRESC_NUM_TEST
vista_query HASH JOIN
vista_query TABLE ACCESS FULL RLUP_ASSIGNED_ACCOUNT
vista_query HASH JOIN
vista_query TABLE ACCESS FULL SHERLOCK_PRODUCT_MAPPING
vista_query TABLE ACCESS FULL PRESCRIP_RETAIL
9 rows selected.
Partition Pruning: This is supposed to provide an insight to the partitions oracle
vists internally...
I guess we can use "month>= add_months(sysdate,-24)" instead of partions too.
I don't think Oracle is visiting any partitions.
I'll also search into all_tab_partitions to verify this.
Explain_Plan for what partitions oracle visits internally (partition pruning):
SQL> ed
Wrote file afiedt.buf
1 explain plan set statement_id='vista'
2 for select * from retail.prescrip_retail
3* where month>= add_months(sysdate,-24)
SQL> /
Explained.
Elapsed: 00:00:00.05
22:13:56 SQL> select statement_id,operation,options,object_name
22:14:28 2 from plan_table
22:14:30 3 where statement_id='vista';
STATEMENT_ID OPERATION
OPTIONS OBJECT_NAME
vista SELECT STATEMENT
vista PARTITION RANGE
ITERATOR
vista TABLE ACCESS
FULL PRESCRIP_RETAIL
Elapsed: 00:00:01.00
Indexes/Constraints on PRESCRIP_RETAIL table:
SQL> ED
Wrote file afiedt.buf
1 SELECT TABLE_NAME,TABLE_TYPE,INDEX_NAME,INDEX_TYPE,PCT_FREE,STATUS,PARTITIONED
2 FROM ALL_INDEXES
3* WHERE TABLE_NAME IN ('PRESCRIP_RETAIL')
SQL> /
TABLE_NAME TABLE INDEX_NAME INDEX_TYPE PCT_FREE STATUS PAR
PRESCRIP_RETAIL TABLE BX6_PRESC_RELID BITMAP N/A YES
PRESCRIP_RETAIL TABLE BX7_PRESC_ME BITMAP N/A YES
PRESCRIP_RETAIL TABLE BX1_PRESC_PROD BITMAP N/A YES
PRESCRIP_RETAIL TABLE BX2_PRESC_PAYER BITMAP N/A YES
PRESCRIP_RETAIL TABLE BX3_PRESC_PAYERCD BITMAP N/A YES
PRESCRIP_RETAIL TABLE BX4_PRESC_PRESC BITMAP N/A YES
PRESCRIP_RETAIL TABLE BX5_PRESC_PFIER BITMAP N/A YES
7 rows selected.
SQL> ed
Wrote file afiedt.buf
1 SELECT TABLE_NAME,CONSTRAINT_NAME,CONSTRAINT_TYPE,STATUS,DEFERRABLE
2 FROM ALL_CONSTRAINTS
3* WHERE TABLE_NAME IN ('PRESCRIP_RETAIL')
SQL> /
TABLE_NAME CONSTRAINT_NAME C STATUS DEFERRABLE
PRESCRIP_RETAIL SYS_C001219 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001220 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001221 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001222 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001223 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001224 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001225 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001226 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001227 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001228 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001229 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001230 C ENABLED NOT DEFERRABLE
PRESCRIP_RETAIL SYS_C001231 C ENABLED NOT DEFERRABLE
13 rows selected.
In all_tables:
NUM_ROWS:2806673860
AVG_SPACE:360
Here is the data size in the table.
SQL> select count(*) from PRESCRIP_RETAIL;
COUNT(*)
4602980312
Again, here is the partition information and the amount of data in each partition:
SQL> ed
Wrote file afiedt.buf
1 select
2 partition_name,SUBPARTITION_COUNT,PARTITION_POSITION,TABLESPACE_NAME,
3 NUM_ROWS
4 from all_tab_partitions
5 where table_name='PRESCRIP_RETAIL'
6* order by partition_name desc
SQL> /
PARTITION_NAME SUBPARTITION_COUNT PARTITION_POSITION TABLESPACE_NAME NUM_ROWS
PRESC200705 0 36 PRESC_PARTITION_29 141147085
PRESC200704 0 35 PRESC_PARTITION_28 140299317
PRESC200703 0 34 PRESC_PARTITION_27 140703128
PRESC200702 0 33 PRESC_PARTITION_26 132592733
PRESC200701 0 32 PRESC_PARTITION_25 145832356
PRESC200612 0 31 PRESC_PARTITION_24 136702837
PRESC200611 0 30 PRESC_PARTITION_23 137421767
PRESC200610 0 29 PRESC_PARTITION_22 140836119
PRESC200609 0 28 PRESC_PARTITION_21 131273578
PRESC200608 0 27 PRESC_PARTITION_20 134967317
PRESC200607 0 26 PRESC_PARTITION_19 130785504
PRESC200606 0 25 PRESC_PARTITION_18 131472696
PRESC200605 0 24 PRESC_PARTITION_17 138590581
PRESC200604 0 23 PRESC_PARTITION_16 126849798
PRESC200603 0 22 PRESC_PARTITION_15 137164667
PRESC200602 0 21 PRESC_PARTITION_14 126938544
PRESC200601 0 20 PRESC_PARTITION_13 135408324
PRESC200512 0 19 PRESC_PARTITION_12 123285100
PRESC200511 0 18 PRESC_PARTITION_11 121245764
PRESC200510 0 17 PRESC_PARTITION_10 122112932
PRESC200509 0 16 PRESC_PARTITION_09 119137399
PRESC200508 0 15 PRESC_PARTITION_08 123372311
PRESC200507 0 14 PRESC_PARTITION_07 112905435
PRESC200506 0 13 PRESC_PARTITION_06 119581406
PRESC200505 0 12 PRESC_PARTITION_05 123977315
PRESC200504 0 11 PRESC_PARTITION_04 118975597
PRESC200503 0 10 PRESC_PARTITION_03 125782688
PRESC200502 0 9 PRESC_PARTITION_02 117448839
PRESC200501 0 8 PRESC_PARTITION_01 122214436
PRESC200412 0 7 PRESC_PARTITION_36 124799998
PRESC200411 0 6 PRESC_PARTITION_35 125471042
PRESC200410 0 5 PRESC_PARTITION_34 118457422
PRESC200409 0 4 PRESC_PARTITION_33 119537488
PRESC200408 0 3 PRESC_PARTITION_32 121319137
PRESC200407 0 2 PRESC_PARTITION_31 115226621
PRESC200406 0 1 PRESC_PARTITION_30 119143031
36 rows selected.
Data in induvidual partition of PRESCRIP_RETAIL.
SQL> SELECT COUNT(*) FROM PRESCRIP_RETAIL PARTITION(PRESC200704);
COUNT(*)
140299317
SQL> SELECT COUNT(*) FROM PRESCRIP_RETAIL PARTITION(PRESC200703);
COUNT(*)
140703128
SQL> SELECT COUNT(*) FROM PRESCRIP_RETAIL PARTITION(PRESC200702);
COUNT(*)
132592733
SQL> SELECT COUNT(*) FROM PRESCRIP_RETAIL PARTITION(PRESC200701);
COUNT(*)
145832356
SQL> SELECT COUNT(*) FROM PRESCRIP_RETAIL PARTITION(PRESC200606);
COUNT(*)
131472696
SQL> SELECT COUNT(*) FROM PRESCRIP_RETAIL PARTITION(PRESC200605);
COUNT(*)
138590581
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Other tables info:
Index of other tables related to PRESCRIP_REATIL:
SQL> SELECT TABLE_NAME,TABLE_TYPE,INDEX_NAME,INDEX_TYPE,PCT_FREE,STATUS,PARTITIONED
2 FROM ALL_INDEXES
3 WHERE TABLE_NAME IN ('RLUP_ASSIGNED_ACCOUNT','TEMP_PRESC_NUM_TEST','SHERLOCK_PRODUCT_MAPPING');
SQL> /
TABLE_NAME TABLE INDEX_NAME INDEX_TYPE PCT_FREE STATUS PAR
SHERLOCK_PRODUCT_MAPPING TABLE SHERLOCK_PRODUCT_MAPPING_PK NORMAL 10 VALID NO
SHERLOCK_PRODUCT_MAPPING TABLE SHERLOCK_PRODUCT_MAPPING_X1 NORMAL 0 VALID NO
SHERLOCK_PRODUCT_MAPPING TABLE SHERLOCK_PRODUCT_MAPPING_BX1 BITMAP 0 VALID NO
SHERLOCK_PRODUCT_MAPPING TABLE SHERLOCK_PRODUCT_MAPPING_BX2 BITMAP 0 VALID NO
SHERLOCK_PRODUCT_MAPPING TABLE SHERLOCK_PRODUCT_MAPPING_BX3 BITMAP 0 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE BX1_RLUP_ASSIGNED_ACCT_PYR BITMAP 10 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE BX2_RLUP_ASSIGNED_ACCT_TOPLVL BITMAP 10 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE BX3_RLUP_ASSIGNED_ACCT_PBM BITMAP 10 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE BX4_RLUP_ASSIGNED_ACCT_AA_FLAG BITMAP 10 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE BX5_RLUP_ASSIGNED_ACCT_AA_CHD BITMAP 10 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE BX6_RLUP_ASSIGNED_ACCT_PBM_FLG BITMAP 10 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE BX7_RLUP_ASSIGNED_ACCT_ACCTID BITMAP 10 VALID NO
RLUP_ASSIGNED_ACCOUNT TABLE PK_RLUP_ASSIGNED_ACCOUNT NORMAL 10 VALID NO
13 rows selected.
Constraints in other tables:
SQL> SELECT TABLE_NAME,CONSTRAINT_NAME,CONSTRAINT_TYPE,STATUS,DEFERRABLE
2 FROM ALL_CONSTRAINTS
3 WHERE TABLE_NAME IN ('RLUP_ASSIGNED_ACCOUNT','TEMP_PRESC_NUM_TEST','SHERLOCK_PRODUCT_MAPPING');
TABLE_NAME CONSTRAINT_NAME C STATUS DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637753 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637754 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637755 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637756 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637757 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637758 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637759 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637760 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637761 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT SYS_C00637762 C ENABLED NOT DEFERRABLE
RLUP_ASSIGNED_ACCOUNT PK_RLUP_ASSIGNED_ACCOUNT P ENABLED NOT DEFERRABLE
TEMP_PRESC_NUM_TEST SYS_C00640536 C ENABLED NOT DEFERRABLE
12 rows selected.
TEMP_PRESC_NUM_TEST does not contain any constraints or index.

Can i use "Oracle Database 12c: Performance Management and Tuning " training for getting certification on "Oracle Database 11g: Performance Tuning 1Z0-054"

i have taken "Oracle Database 12c: Performance Management and Tuning new" training from oracle university. Now i would like to get certified on "Oracle Database 11g: Performance Tuning 1Z0-054" exam. Is it possible ?

I essentially endorse and refer you to Matthews' and John's post above.
I would differ with slightly with Matthew because my guess is you would often be able to use like for like 12c training for an 11g certification ( I believe there are precedents). BEFORE ANYONE ASKS THE OTHER WAY DOESN'T HAPPEN.
.... but totally concur with Matthew you would ill advised to procede on that basis without one of:
- This being advertised as possible on the website : e.g. https://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=654&get_params=p_id:169 ... option 2 show courses.
- Confirmation from Brandye
- Confirmation from an Oracle Certification Support Web Ticket ( http://education.oracle.com/pls/eval-eddap-dcd/OU_SUPPORT_OCP.home?p_source=OCP )
... The more common (and in my opinion usually better) way would be get your 11g DBA OCP ( or higher first) and then take the 1z0-054. I am almost certain they will accept your 12c course for the 11g DBA OCP.
If you are choosing the route of not being a 11g (or 12c ) DBA OCP first but are on option 2 and relying on the course for certification then the issue is more in the balance and you are even more strongly advised to get confirmation before proceding (remember if the rules need to be changed for you only then any profit out of the exam is lost).
In general my understanding is Oracle would prefer to encourage people to train on the latest version of product that is available for training and will prefer to avoid restrictions which would cause you to train at a lower version. ( This is simply my guess at Oracle University Policy ... personal opinion only).
Having said all I have said I'd encourage you to go with the advice of the earlier two posts.

Should OS/FileSystem caching be write-through?

I have a question. I use Ubuntu. Should I mount my filesystem (which holds BDB's content) with "-o sync" option? That is, should my file system cache be write-through?
I have this question because, if I turn on the logging feature in Berkeley DB but let the file system cache be write-back, I don't exactly know if the log is properly flushed to the disk or not.

Thanks George. I agree that mature applications would be better off mounting their filesystem with "-o sync" option.
But here is a thing: I ran an example test case where I inserted 10 million key-value pairs with logging enabled, and saw that the average response time per insertion was 10 milli seconds, and I did the same experiment with logging disabled and saw that it too took 10 milliseconds per insertion on an average.
For the experiment with logging enabled, I create the environment with DB_INIT_LOG and DB_INIT_TXN flags but don't surround the insertion requests with txn_begin() and txn->commit(). I guess this way of doing insertions is called autocommit. I am hoping I am doing this experiment right.
Thanks for the pointers about set_flags() and DB_TXN_NOSYNC, I am going to look them up.

TimesTen Cache Connect support for Oracle 11g

The latest 7.0.5 readme mentioned that "Oracle Release 11gR1 is supported with TimesTen Cache Connect to Oracle on Linux x86 32-bit and 64-bit platforms, and on Windows 32-bit."
What about Solaris 10? It looks like on Solaris 10 only Oracle 10gR2 being supported. What is so specific about Oracle 11?
Thank you,
Alex

TimesTen 7.0.5 can be used to cache data from different versions of Oracle database.
The reason why the support for Solaris, AIX, and HP-UX were not at the same time as the Linux platform was because Oracle database 11g was not available on those platforms initially. So TimesTen 7.0.5 was certified to support only the ones available first, and support for other platforms was added as 11g became available on those platforms. It was just timing of the certification, code base is the same.
Susan

Can information in cache accessed outside of Oracle DB after shutdown?

Hi All,
I read that the information in caches can be accessed outside of Oracle DB and the buffered Cache must be emptied at shut down of Oracle DB.
Questions:
1. Is it possible to access cache outside of Oracle DB? If yes, how can one read it?
2. Is the information in the cache stored on a persistent storage (file) and can be accessed if the user has permissions on the OS?
Thanks,
Hozy
Edited by: Hozy on Jul 3, 2009 12:38 PM

1. It is possible to access SGA of a running instance with C code but this is not supported by Oracle. See http://oraperf.sourceforge.net/presentations/SGA_access.ppt
2. I don't think this is possible.
Edited by: P. Forstmann on Jul 3, 2009 9:13 AM

Caching configuration (Times Ten - Oracle 10g)

Hi all,
I have managed to setup Times Ten and get a cache group configured against a table in an oracle 10g instance.
That all works so great. My question is how do I define a set of cache groups and get Times Ten to load them in automatically all together. So what I am saying, is I dont want to have to enter these cache group definitions in manually via ttisql command line (as I have done this time).
Could someone please point me in the right direction with this? Also I would like to be able to set TT up such that the cache agent is automatically started. Is this possible?
Thanks,
Dan

Hi Dan,
In the same way that you can create cache groups through a ttIsql script you can also load them from a script using the LOAD CACHE GROUP and REFRESH CACHE GROUP commands.
However, let's remember that TimesTen is a persistent database and so you should not need to re-create the cache groups nor re-load them just becasue you have stopped and started TimesTen. The cache group definitions and data will still be present as they are persistently stored. Also, if you have a READONLY or USERMANAGED cache group using AUTOREFRESH then the changes that occur in oracle are captured and refreshed to the cache group(s) automatically.
As for starting the cache agent 9or the repagent0 automatically, this kind of depends on how you are managing the startup/shutdown of the cache datastore (i.e. what itss ramPolicy is). You can set the cachePolicy for the datastore using ttAdmin as follows:
ttAdmin -cachePolicy always DSNname
this tells TimesTen that the cache agent should always be running for this datastore. However, a side effect of this is that the datastore will allways be loaded in memory when the TimesTen instance is up (i.e. the TimesTen main daemon is running). If you want to be able to start and stop the datastore manually (or from a script) then you will likely be using a ramPolicy of manual and running some script to load/unload the datastore into/from memory. If so then just add the relevant ttadmin -cacheStart|-cacheStop commands to that script.
Chris

Sequence caching with toplink and oracle caching

Hi,
In my application, I use toplink as a JPA provider. For performance reasons, I defined an allocationSize on sequence generator for some persistence objects. I read some documentation to understand how it works, the result of my research is that the allocationSize of sequence generator must match with the increment value of the sequence in database.
So if I want to cache 1000 of values, I must define on my sequence generator allocationSize of 1000 and create a sequence like this : create sequence myseq increment by 1000. Am I right ?
Second question, what if my sequence define a cache in the database. For example, create sequence myseq increment by 1000 cache 20.
Does it mean that 20 values will be cached or 1000*20 values will be cached ? Is the cache size defined per session or for all the sessions of the database ?
Thanks.
Will.

Thank you for your response.
I used the default parameter of toplink (increment by 50) and I left a cache size of 20 on database side.
But I noticed that whenever the server restarts, I "lost" between 900 and 1000 ids (nearly 20*50). So even if sequence cache on oracle size is non transactional, I think there is a kind of prefetch somewhere on the server side. I must not lost more than 50 ids when a server restarts.
If I remove the cache on database side, then the behavior is correct (the expected one to be more precise).
Is there any kind of sequence caching in oracle jdbc drivers ?
Thanks.
Will.

Cache usage

Our application has a table that is repeatedly queried; the queries may contain predicates involving non-primary key columns. Ideally, we would want to cache this entire table in memory to speed up retrieval. We are checking to see if TopLink's cache can do the needful for us.
From browsing the documentation and the forum, it appears that TopLink displays the following behaviour -
1. By default, the database is bypassed and the cache is used only when queries contain primary-key predicates.
2. Direct usage of SQL queries will lead to the cache being bypassed and the database being used; only Expression objects result in the the usage of the cache provided point 1 above is satisfied.
3. The CheckCacheThenDatabase option has to be configured in order that queries with predicates involving non-primary key columns run against the cache.
Are the points listed above valid? Any suggestions or corrections would be highly appreciated.
Thanks,
CR

These statements are all accurate. By default, only PK queries hit the cache only, all hard coded SQL queries will go to the database and you can configure each query on an individual basis to hit the cache first or go straight to the database.
Note that some advanced queries must always go to the database, i.e., queries with subqueries.
- Don

Tuning filesystem cache usage to benefit Oracle db workloads

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