Tuesday Jun 30, 2015

Upgrading Demantra 7.3.1.x to 12.2.x can produce duplicate rows. There are two ways to solve this issue.

Upgrading Demantra 7.3.1.x to 12.2.x can produce duplicate rows.  There are two ways to solve; apply 21089579 before your upgrade to 12.2.x or wait for 12.2.5.1.  The platform upgrade resolves this issue in 12.2.5.1.  Apply this patch before your upgrade from 7.3.1.x to 12.2.x.  After an application upgrade SITE_TYPE_CODE, SITE_TYPE_DESC, ACCT_TYPE_CODE, ACCT_TYPE_DESC columns do not have a default '0'.  Please note that this patch does not remove any existing "duplicate" rows in ITEMS, LOCATION, MDP_MATRIX or SALES_DATA.


Upgrading from Demantra 7.3.1.x to 12.2.x? This can produce duplicate rows. There are two ways to solve. See patch 21089579 and the details in this note. (Doc ID 2025954.1)

Thursday Jun 18, 2015

Demantra Certification Study Guides, Exam Preparation

Hello All!   We have the certification documents available!  They are located at

https://community.oracle.com/docs/DOC-916146

There you will find:

  • The PDF from May 2015 webcast, Demantra Certification.  Are you attempting to get certified?  Let's walk through the process!
  • Mfg_DEM_Advisor_Webcast_2015_0610.pdf
  • Mfg_DEM_Advisor_Webcast_Certification_2015_0610-Part-2.pdf
  • Demantra-Certification-Technical.pdf
    • This is still in draft however, plenty of technical points that will add to your understanding of Demantra troubleshooting and management
  • Demantra-Certification-Topics.pdf

Of course, there are plenty of webcasts, as noted in Demantra-Certification-Topics.pdf.  Remember, the test is based on 7.3.1.4.  I would advise that you stay with manuals that are available for 7.3.1.4 as made available at Oracle Demantra Documentation Library, DOCs, TOIs and Training Available(Doc ID 443969.1). 

There is one more site that will help you drill into specific topics.  This site has whitepapers from Demantra DEV and Support Proactive Services that will provide detailed analysis and direction to Demantra functional and technical topics.  The MOS note is:

Development and Proactive Services Document Library. CRITICAL Updates, Comprehensive, Impactful White Papers, Guides, Notes +! Oracle Value Chain Planning Suite ASCP GOP Demantra RP APCC SNO IO DSR PS SPP, Note 1669052.1

Additionally, the Demantra Information Center is being updated and integrated into the NEW Value Chain Planning (VCP) Information Center!  I will provide details as soon as they are available.

As always, feel free to contact me.   Best to you in your efforts!   Jeff

Friday May 22, 2015

Demantra Worksheet Performance - A summary guide at Customer Request

Worksheet performance.  There are dozens of notes.  It can be challenging to find the best approach. 

  • If you are on 7.3.1.4 or greater, see the following three notes.  Upgrade to the latest version of TABLE_REORG.  Run TABLE_REORG with the 'T' option and review the suggestions in the LOG_TABLE_REORG table.
  • Demantra TABLE_REORG procedure. Did you know that TABLE_REORG has replace rebuild_schema mad rebuild_tables?(Doc ID 2005086.1)
    - Demantra TABLE_REORG Tool New Release with Multiple Updates! Partitions, DROP_TEMPS and More! 7.3.1.3 to 12.2.x.(Doc ID 1980408.1)
  • If you have an error: Demantra table_reorg Procedure Failed ORA- on sales_data mdp_matrix promotion_data How do I Restart? rupd$_ mlog$_ I have Table cannot be redefinitioned in the LOG_TABLE_REORG table(Doc ID 2006779.1)

I would consider these notes to be the best regarding worksheet performance:

  • Oracle Demantra Worksheet Performance - A White Paper (Doc ID 470852.1)
  • Oracle Demantra Worksheet Performance FAQ/TIPS 7.3+! (Doc ID 1110517.1)
  • Demantra 12.2.4 Worksheet Performance Enhancements Parameter dynamic_hint_enabled, Enable Dynamic Degree of Parallelism Hint for Worksheets. 
  • Development Recommended Proper Setup and Use (Doc ID 1923933.1)
  • Demantra Development Suggested Performance Advice Plus Reference Docs (Doc ID 1157173.1)
  • Oracle Demantra Worksheets Caching, Details how the Caching Functionality can be Leveraged to Potentially Increase Performance (Doc ID 1627652.1)
  • The Column Prediction_Status, MDP_Matrix and Engine. How are they Related? Understand Prediction_status Values (Doc ID 1509754.1)

Also, see:
Demantra Gathering Statistics on Partitioned Objects Oracle RDBMS 11gR2 (Doc ID 1601596.1)
- Demantra 11g Statistics new Features and Best Practices Gather Schema Stats (Doc ID 1458911.1)

I would review all parameters mentioned in the docs above and:

1. Monitor the workstation memory consumption and CPU utilization as the worksheet is being loaded.
   * You may have to adjust the memory ceiling for Java
2. Manage MDP_MATRIX.  Are there dead/unused combinations?  When running the engine, you can manage the footprint of the input.  If MDP_MATRIX
   is carrying sizeable dead combinations and/or entries without a matching entry in SALES_DATA, you are increasing processing load.  Check out
   note 1509754.1.  The attachment explains the principle.
3. Using the notes above, can you cache?  Can you use filters?  Can you use open with? 
   A series can be cached, aggregated by item and cached in the branch_data_items table.  This improves performance of worksheets that are aggregated
   across locations and that do not have any location or matrix filtering.
4. Run the index advisor.  Does it suggest additional indexes? 
5. If you do not have the index advisor, produce an AWR.  The AWR should be taken when the user opens the worksheet.  For example, start the AWR process. 
   Wait 10-15 minutes.  Tell the user to open the worksheet.  After the open succeeds, wait 10 minutes.  Stop the AWR process.  What are the top SQLS? 
   What are the contentions?
6. Do you have your large tables on their own tablespace?  This means each large table has a tablespace to its self.  Each large index has a
   tablespace to its self.
7. The worksheet is retrieving rows to display.  Is there row chaining causing multiple block reads?  That should be revealed in the AWR or run the
   appropriate SQL.
8. Worksheet design is important.  The worksheet designers setup what they need.  However, that does not mean that the worksheet design blends well
   with available processing capabilities.  Know the forecast branch health.  I think this is discussed in 1509754.1.  The following SQL reveals the
   tree:

   select level_id,count(*) from mdp_matrix
   where prediction_status = 1
   group by level_id
   order by level_id

   If you have a branch that is 100000 and remaining branches at 5000 and 10000 that is a problem.  That would point to a setup/design issue.
   Meaning that if you have branch as a level and it just so happens that 1 branch indeed has 100,000 and the other 2 branches account for smaller
   volumne, 5000 and 10000, the chosen levels of the worksheet need to be revisted.  Perhaps a level lower than branch is better suited to
   processing the data.  While this and #2 above are probably out of your control, it will help explain the worksheet loading and engine processing
   time.
9. Reduce the amount of memory that your worksheet selects:
   - Remove series if possible
   - Reduce the span of time
   - Apply filters
10. Review all server and client expressions.  Are they affecting performance?
11. Run DROP_TEMPS

Wednesday May 13, 2015

TABLE_REORG Causing ORA-42012: error occurred while completing the redefinition and ORA-00600

Hello!  The latest information for you.

Submitting the TABLE_REORG procedure for a table that has a foreign key constraint that refers to the same table, leaves the constraint in a disabled state.  However, Foreign key constraints that refer to other tables, behave as expected. i.e., the constraint is re-enabled at the end of the redefinition.

When this condition exists, TABLE_REORG will fail with the following:

ORA-42012: error occurred while completing the redefinition
ORA-00600: internal error code, arguments: [17183], [0x3FFF81BF400], [], [], [], [], [], [], [], [], [], []

It does generate a trace file and dump file.

ERROR at line 1:
ORA-42012: error occurred while completing the redefinition
ORA-00600: internal error code, arguments: [17183], [0x3FFF81BF400], [], [], [], [], [], [], [], [], [], []
ORA-06512: at "SYS.DBMS_REDEFINITION", line 82
ORA-06512: at "SYS.DBMS_REDEFINITION", line 1524
ORA-06512: at line 1
ORA-06512: at "DEMANTRA.TABLE_REORG", line 1193

To resolve this issue, please apply Patch 13867469 if available for your database version and platform.  The fix for Bug 13867469 should be included in 12.2 future release.

- See MOS Note <Note 13572659.8> for additional details.  Bug 13572659 - DBMS_REDEFINITION disables Foreign Keys used for REFERENCE partitioning

- Also available, patch 20954948 : MERGE REQUEST ON TOP OF 11.2.0.3.0 FOR BUGS 13040943 13572659 13642044

As a workaround, if you did not receive an ORA-00600, re-enable the constraint after the redefinition.

Note: The above workaround is not applicable for a nested table built on a partitioned parent table. Reference: <Note 1929007.1>.
Foreign Constraint On Nested Table is Created With Status Disabled.

Tuesday May 05, 2015

Demant TABLE_REORG Procedure Failed ORA- on SALES_DATA MDP_MATRIX PROMOTION_DATA How do I Restart? RUPD$_ MLOG$_

When you submit TABLE_REORG, DBMS_REDEFINITION is used.  This will create an MLOG$_ database object.  The table you supplied for the TABLE_REORG procedure has a Primary Key (PK).  Since there is a PK on the table, when DBMS_DEFINITION creates the MLOG$_ object, DBMS_REDEFINITION automatically creates a RUPD$_ object.  These objects are meant to be used for Java RepAPI.  If you execute a 'drop snapshot log on tablename' the snapshot log as well as the temporary snapshot log are dropped.  However, dropping the MLOG$_ object is not best practice. 

If these objects exist prior to executing TABLE_REORG, you will see the following: ‘Table cannot be redefinitioned.' in log_table_reorg table.  This means that one or both objects/segments exist.  For example, if I had a table_reorg for mdp_matrix fail, the following segments would most likely be left behind:

RUPD$_MDP_MATRIX
MLOG$_MDP_MATRIX

Use the following SQL to verify (10g and above):

select substr(object_name,1,30)
from dba_objects
where regexp_like( object_name, 'MLOG$|RUPD$')
and owner = '&Schema_owner'

While you can drop these temporary RDBMS segments, it is best practice to use the following:

BEGIN
 DBMS_REDEFINITION.ABORT_REDEF_TABLE (
   uname       => '&demantra_schema_name',
   orig_table  => '&original_table_name',
   int_table   => '&interim_table_name');
END;

In the above, supply the arguments:

- DM or your schema name
- MDP_MATRIX is the original_table_name
- MLOG$_MDP_MATRIX is the interim_table_name

Verify that the objects are dropped.  Submit the TABLE_REORG again AFTER repairing the cause of the last failure.

Wednesday Apr 29, 2015

Did you know that TABLE_REORG has replace REBUILD_SCHEMA mad REBUILD_TABLES?

Demantra TABLE_REORG procedure. 

Did you know that TABLE_REORG has replace REBUILD_SCHEMA mad REBUILD_TABLES?  TABLE_REORG
can addressed partitioned tables and is more efficient!  Get the latest release at My Oracle Support using bug 17640575.

TABLE_REORG has really replaced and improved the functionality of REBUILD_SCHEMA and REBUILD_TABLES.
It rebuilds the table which is done in primary key order and it moves empty columns to the end of the row.

REBUILD_SCHEMA uses ALTER TABLE MOVE tablespace to reduce chained rows of all tables in the schema.
However, it does not support partitioned tables.

REBUILD_TABLES  is the similar.  It was originally designed for MDP_MATRIX / SALES_DATA, but it can run for all tables and
also for a specific table.  From 2010 it does support partitioned tables.

The procedure MOVE_TABLE was fixed to handle partitioned tables.  It is also out of date, I see ANALYZE TABLE has used parts of the
code (eg for SALES_DATA and MDP_MATRIX).  For an "all tables run" is uses ANALYZE_SCHEMA that does use dbms_stats.GATHER_TABLE_STATS

All tables  - Where the stats value chain_cnt > 0, it does not automatically include SALES_DATA unless 'sys_params','Rebuild_Sales_Table' = 1.

REBUILD_TABLES ( table namel,  stats check,  sales,  all tables flag)

exec REBUILD_TABLES ( null, 1, null, 1) ;    -- With ANALYZE_SCHEMA(100000)  = for none or really old stats
exec REBUILD_TABLES ( null, 0, null, 1) ;

exec REBUILD_TABLES ( null, 0, 1, 1) ;   -- Will include SALES_DATA

For more information see: Troubleshooting TABLE_REORG Package issues - RDF Snapshot drop when process fails + TABLE_REORG Guide MOS Note 1964291.1


Gathering statistics on partitioned tables.  Best practice:

For all 11gr2 environments with large partitioned or subpartitioned objects turn on incremental statistics using this command:

exec dbms_stats.set_table_prefs('OWNER','TABLE','INCREMENTAL','TRUE');

Once this is set for any given table, gather statistics on that table using the normal tool (fnd_stats in ebs or dbms_stats elsewhere).
This first gather after turning it on will take longer than previous analyzes.  Then going forward we will see the following:

1.  The normal dbms_stats or fnd_stats, will only gather statistics on lower level partitions if the statistics on that partition are stale.  This is a significant change.  That is going forward using the default options of a gather command may in fact perform no re-analyze on the actual data if the modifications to the table do not warrant it.

2.  If a subpartition is stale the normal stats will ONLY gather statistics on that subpartition.  The partition for that subpartition will be re-derived as will the global
    statistics, no other statistics will be gathered.

Making this change promises to reduce gather stats by hours in some cases.

For more information: Demantra Gathering Statistics on Partitioned Objects Oracle RDBMS 11gR2, MOS Note 1601596.1

Monday Apr 27, 2015

The table_reorg procedure ran for SALES_DATA errored due to lack of tablespace. Can I delete the RDF segments?

Yes, you may delete these temporary rdbms_redefinition tables.  They are snapshots of the table to be reorganized.  The redefinition requires creating a
snapshot.  While you can use SQL to release the RDF segments, it is advised that you call the dbms_redefinition.abort_redef_table to release the snapshot.  Then re-start the procedure.  The dbms_redefinition.abort_redef_table procedure requires three parameters: schema, original table name, interim table name.

Use the following or SQL

BEGIN
  DBMS_REDEFINITION.ABORT_REDEF_TABLE (
    uname       => '&demantra_schema_name',
    orig_table  => '&original_table_name',
    int_table   => '&interim_table_name');
END;
/

Thursday Apr 02, 2015

Demantra Installing 12.2.4.1 as SYS or SYSTEM Installer Fails or is Failing

We are aware of a bug that might raise an error during the installation of the 12.2.4.1 Generic Patch recently released.

In some cases, when using SYS as the DBA user and “Enable Automatic Table Maintenance” checkbox has been checked, sys_grants.sql script which is being
run as part of the installation may fail.

sys_grants.sql is using an internal function in with a specific combination of hardware/platform may generate invalid value.

Run the installer using SYSTEM and not SYS, then, after the installation completes, replace sys_grants.sql with the attached file and run it as sys.
Make sure to add “TRUE” as the 4th parameter.

For example:

@sys_grants.sql DEMANTRA ACL_DEFAULT ACL_DEFAULT TRUE

This has been addressed in release 12.2.5.1.

Also:

Uptake of VCP 12.2.4.1 is mandatory for all VCP and Demantra 12.2.4 installations.

Are you already at 12.2.4.1?

Demantra 12.2.4.1 has a new required patch 19945449, ARU# 18420277, Demantra patch 12240066 - is now available. It was discovered that the engine throws a segmentation fault while running CDP consumption profile.  Please see the additional information in the readme Notes.

Reference Notes:
Oracle Demantra Post Release 12.2.4.1 Mandatory Patch Application - Patch 19945449 (Doc ID 1960180.1)
Demantra 12.2.4.1 Cumulative Patch. This CU is Specifically for r12.2.4.1. There are 13 Issues Patched and or Improved. (Doc ID 1952805.1)
Oracle Demantra Release Notes for Release 12.2.4.1 (Doc ID 1947062.1)
Demantra Release 12.2.4.1 Known Upgrade and Known Product Issues with Workarounds (Doc ID 1948769.1)
Oracle Demantra Demand Planning Announcing New Release 12.2.4.1 is Now Available (Doc ID 1948684.1)
Troubleshooting Demantra 12.2.4.1 Installation (Doc ID 1986634.1)

 

Wednesday Apr 01, 2015

New SQL to Determine Out of Order Ratio and Cluster Factor

Hello!  Please run the following for both mdp_matrix and sales_data.     Questions?  Email at Jeffery.goulette@oracle.com

1. The first SQL will need to be adjusted to accommodate your PK for sales_data and your PK for mdp_matrix.  Adjust the select and from clause to match your PK.   In the case of this sample, the PK was:

ITEM_ID
LOCATION_ID
SALES_DATE
IS_T_EP_SPF


-- ShowOOR.sql

SELECT (ROUND((
 (SELECT COUNT(*) AS CNT
 FROM
   (SELECT ITEM_ID,
     LOCATION_ID,
     SALES_DATE,
     IS_T_EP_SPF ,
     RELATIVE_FNO ,
     BLOCK_NUMBER ,
     ROW_NUMBER ,
     DATA_ROW ,
     (LAG(DATA_ROW) OVER(PARTITION BY RELATIVE_FNO, BLOCK_NUMBER ORDER BY ROW_NUMBER)) AS PREV_DATA_ROW
   FROM
     (SELECT ITEM_ID,
       LOCATION_ID,
       SALES_DATE,
       IS_T_EP_SPF ,
       RELATIVE_FNO ,
       BLOCK_NUMBER ,
       ROW_NUMBER ,
       (DENSE_RANK() OVER(PARTITION BY RELATIVE_FNO, BLOCK_NUMBER ORDER BY ITEM_ID,LOCATION_ID,SALES_DATE,IS_T_EP_SPF)) AS DATA_ROW
     FROM
       (SELECT ITEM_ID,
         LOCATION_ID,
         SALES_DATE,
         IS_T_EP_SPF ,
         DBMS_ROWID.ROWID_RELATIVE_FNO(ROWID) RELATIVE_FNO ,
         DBMS_ROWID.ROWID_BLOCK_NUMBER(ROWID) AS BLOCK_NUMBER ,
         DBMS_ROWID.ROWID_ROW_NUMBER(ROWID)   AS ROW_NUMBER
       FROM SALES_DATA
       ) C
     ) B
   ) A
 WHERE DATA_ROW != PREV_DATA_ROW
 AND DATA_ROW   != PREV_DATA_ROW + 1
 )                               /
 (SELECT COUNT(*) FROM SALES_DATA
 )),3)*100) AS "Out Of Order Ratio %"
FROM DUAL;


-- ShowCF.sql
undefine table_name
SELECT ui.index_name, us.blocks as "Table Blocks", ui.clustering_factor as "Index clustering Factor", ut.num_rows as "Table Rows"
FROM   user_indexes     ui,
       user_tables      ut,
       user_constraints uc,
       user_segments us
WHERE  ui.table_name = ut.table_name
AND    ut.table_name = uc.table_name
AND    ui.index_name = uc.index_name
AND    ut.table_name = us.segment_name
AND    us.segment_type = 'TABLE'
AND    uc.constraint_type = 'P'
AND    ut.table_name      = '&table_name';

Thursday Feb 26, 2015

Setting Worksheet Related Parameters and Hardware Requirement Example

 Hello!   This is an example when determining how to set critical aps_params for worksheet performance:


If you expect to have 150 users with concurrency rate of 30% your setting and hardware should be:

   50 users * 30% = 45 users

   threadpool.query_run.per_user = 8

   threadpool.query_run.size = Number of concurrent users * threadpool.query_run.per_user (8) = 360

   MaxDBConnections = threadpool.query_run.size + 10 = 370

   To run a production environment with those setting you should have:

   Database: DB machine with 60 CPU's (= MaxDBConnections / 6 = 60)

   Application Server: AP with 27 CPU's (= threadpool.query_run.size/16) + 4), 4GB of memory

Only with this hardware you can run Demantra with 150 users with concurrency rate of 30%, is your hardware powerful enough for your environment?

Tuesday Feb 17, 2015

Demantra Table_Reorg. A new version has been released!

Demantra Customers, there is a new release of the table_reorg Tool.  This patch will install updates to the TABLE_REORG tool.  Demantra Version: 7.3.1.x and 12.2.x.  The minimum 7.3.1.x version is 7.3.1.3.   You can download this patch using bug 17640575 in My Oracle Support.  For additional information see MOS note:
Demantra TABLE_REORG Tool New Release with Multiple Updates! Partitions, Drop_temps and More! 7.3.1.x to 12.2.x. (Doc ID 1980408.1)

Friday Feb 13, 2015

Demantra Table Reorganization, Fragmentation, Null Columns, Primary Key, Editioning, Cluster Factor, PCT Fee, Freelist, Initrans, Automatic Segment Management (ASM), Blocksize....

Hello All!   Why does Demantra require table reordering and null column movement on a, what seems to be, frequent basis?  Your other apps do not require this type of action.  Can this be explained?   I can give you the following.  Let me know if you have questions.  Thank You!   Jeff

 

Addressing the reason why Demantra requires frequent reordering/reorganization and null column placement, I can explain the reason as follows.  As data is inserted into the Demantra table it will not be in any particular order.  The null columns will be scattered throughout the row.  The main quest is to increase throughput and reduce contention.  Since Demantra is both OLTP and data warehouse the apps DBA must tune accordingly.  Of course EBS and VCP applications have elements of both OLTP and data warehouse but are largely transaction processing at their core.  Applications such as EBS and VCP can typically provide satisfactory response time using typical DBA tuning methods.  Specifically, indexing and proper SQL tuning is plenty to improve and maintain acceptable performance.  However, large tables in data warehouse implementations require unique DBA tuning techniques to reduce IO when accessing the big database tables.  Reducing wait times by eliminating contention is the main goal of table reorganization and the movement of null columns to the end of the row.  The data warehouse requirements of Demantra are no different than other data warehouse applications.

By themselves these are not unique and are implemented in data warehouse applications every day.  For each and every read operation we want to fetch as many relevant rows as possible.  To that end we reorder the large tables according to the PK of each table.  The PK is the main access method to the data according the business requirement.  In the case of Demantra, the PK chosen covers approximately 80% of the data access needed for the main forecasting worksheets.  The rest are addressed using typical DBA tuning methods.  There are new booked, shipped orders inserted into the Demantra world daily, weekly, etc.  When this occurs, the rows naturally loose table/index locality and thus the selectiveness is reduced.  This increases the cluster factor because the number of read operations increases to fetch the desired rows.  The CBO recognizes this and calculates the access method accordingly. 

We want to assist the CBO decision making process as much as possible.  If data was static this effort would be greatly reduced.  Because the Demantra data is dynamic, we need to push the CBO our way to deliver the access plan we desire.  If the table is in Primary Key (PK) order, making your Out of Order Ratio (OOR) low, rows are brought into the SGA in sequential order.  Reducing muli-block reads to process data.  The Cluster Factor (CF) is closely related to OOR.

To review the cluster factor concept, see Demantra Large Database Object Diagnosis and Maintenance Best Practices for Best Performance (Doc ID 1629078.1)

The selectivity of a column value, the db_block_size, the avg_row_len and the cardinality all work together in helping the optimizer to decide whether to use an index versus a full table scan.  If a data column has high selectivity and a low CF, then an index scan is usually the fastest execution method.  Once your large tables are in PK order with a low CF, performance can increase dramatically.  The main goal of table reorganization is to reduce IO when accessing the big database tables.  What it does is two main things:

1. Reorders the table data according to the primary key index.
2. When using the “C” which stands for column reordering, it also pushes columns that have no data, nulls, to the end of the table row. This is good thing for tables having a high number of rows as Oracle works in a 254 columns chunks.

Some of the larger Demantra tables have upwards of 200+ columns.  Since every customer uses the Demantra tool in a different manner a portion of these columns will naturally be left as null.  Pushing the null columns to the end of the row decreases data access waits or contention by streamlining the fetch action.  The end result is a column ordered, less fragmented table that will reduce the IO operations for range operations, for example scan data between dates.  The cluster factor will be lower and thus the CBO will look at our desired access method favorably.

Demantra is sensitive to database scans therefore reviewing and implementing sound database performance techniques is essential.  While the EBS and Value Chain Planning (VCP) RDBMS can provide adequate response with proper statistics, indexes, tuning and patching, Demantra brings processing methods to the table that require tighter controls.  I will highlight some of these areas that require tighter control.

1) Tables that have 300+ columns many of the columns are null.  The columns are in the table to represent the family of Demantra solutions.  For
   example Demand Planning, Advanced Demand Planning, Promotion Planning, S&OP, etc.  When the null columns are pushed to the end of the row, the
   read operation becomes streamlined thus increasing performance.

2) Demantra moves significant amounts of data to and from the disk.  It behooves the implementer/Applications DBA to implement a strategy that reduces wait constraints.  Here is a sample of techniques that require strategic implementation attention:

   - Block size 16k or larger
   - PCTFREE set at 30% to 40%
   - FREELIST increased according to your particular implementation
   - INITRANS increased according to your particular implementation
   - Statistics maintained at a 30% sample or larger
   - Parallel Processing at every possible contention point
   - Redo size appropriate to keep switches at 3-4 per hour
   - No Automatic Segment Management (ASM)
   - No Editioning
   - Partitions implemented
   - Large SGA to accommodate multi-block reads
   - Synchronous IO implemented
   - Careful setting of Demantra CBO parameters


In conclusion, it is true that Demantra requires RDBMS implementation strategies that are unique but not uncommon for OLTP and Warehouse systems.
However, VCP requires a unique trick that is unique to VCP.  Creating statistics on empty MLOG$ objects then locking the statistics to the object.
It has been proven that this increases performance by reducing a bottleneck.

Reference Notes:
- Demantra Out of Order Ratio, Table_reorg Procedure, Partitions and Clustering Factor - Manage Your Demantra Database Objects (Doc ID 1548760.1)
- Demantra DB Health and Performance: Oracle Demantra Database Best Practices - A White Paper / Demantra Performance Clustering Factor Out of Order Ratio TABLE_REORG CHECK_REORG (Doc ID 1499638.1)
- Demantra Performance Clustering Factor Out of Order Ratio TABLE_REORG CHECK_REORG (Doc ID 1594372.1)
- Demantra How to Use TABLE_REORG to Reorder MDP_MATRIX in Primary Key (PK) Order Action Plan Version 7.3.1.3 and Later. See 1085012.1 Prior to 7.3.1.3 (Doc ID 1528966.1)
- Demantra Large Database Object Diagnosis and Maintenance Best Practices for Best Performance (Doc ID 1629078.1)
- Demantra Large Database Object Diagnosis and Maintenance Best Practices for Best Performance (Doc ID 1629078.1)

Tuesday Jan 20, 2015

Demantra Large Table Partitions and Using the Flashback Recycle bin, recyclebin, dba_recyclebin and sys.RECYCLEBIN$ Purge Best Practice

This is covered using MOS note:

Demantra Large Table Partitions and Using the Flashback Recycle bin, recyclebin, dba_recyclebin and sys.RECYCLEBIN$ Purge Best Practice (Doc ID 1962730.1)

When you are using the  feature and Oracle partitions are involved you will need to perform additional due diligence.  After the automatic
purge that occurrs when the quota is reached or after you issue a purge command to the recyclebin, you will notice that there are orphaned
BIN$ objects that consume the same space as the original partition that was dropped and the purged.

 

This was the solution based off of a customer SR that puzzled us at first.  The flashback documentation does not discuss the flashback purge
and partitions.  We recommend following the current best practice when managing the flashback feature and partitions.

If you have already performed or if the auto purge has occured, you will need to perform the following.  Of course customized to you BIN$ object name:

ALTER SESSION SET RECYCLEBIN=OFF;
drop table lpudemantra."BIN$A3+yI1NBASrgUwoVBkIBKg==$0";
drop table lpudemantra."BIN$A4gGznhiAVbgUwoVBkIBVg==$0";
.
.
.
.
drop table lpudemantra."BIN$9WCVYRl3BGbgQwoVBkIEZg==$0";

If you have not experienced the purge of the recycle bin, attempt the following:

  1) select count(*) from sys.recyclebin$;

  2) Instead of simply trying to purge the table we can use the following alternative:

     a) flashback table <table_name> to before drop;

          or

          if  <table_name> is currently used by another object:

        flashback table <table_name> to before drop rename to <new_table_name>;


     b) create a script that will drop all the partitions one by one :

        spool drop_<table_name>_partitions.sql

        select 'alter table '|| table_owner|| '.'|| table_name ||' drop partition '|| partition_name||';'
        from dba_tab_partitions
        where table_name='<table_name>'
        /

        spool off


     c) run drop_<table_name>_partitions.sql


     d) drop table <table_name>;


     e) purge recyclebin;


To turn off the recyclebin
  - alter system set recyclebin=off scope=spfile;

Friday Jan 09, 2015

Demantra 12.2.4.1. Are you upgrading or have upgraded? New Mandatory Patch is available.

Are you already at 12.2.4.1?  Demantra 12.2.4.1 has a new required patch 19945449, ARU# 18420277, Demantra patch 12240066 - is now available.
It was discovered that the engine throws a segmentation fault while running CDP consumption profile.  Please see the additional information in the readme Notes.

Wednesday Dec 10, 2014

Hello Demantra Customers! Are you at version 12.2.4.1? A new cumulative patch will be released soon.

Hello Demantra Customers!  Are you at version 12.2.4.1?  A new cumulative patch will be released soon.  This 12.2.4.1 cumulative patch is different to the 12.2.x patch strategies in the respect
that it will only contain fixes that are new to 12.2.4.1.  This cumulative patch is scheduled to be released later this month, December 2014.  To monitor, see this note, 1952805.1 or visit the Oracle Demantra BLOG at https://blogs.oracle.com/demantra/
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