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 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

Friday Sep 27, 2013

Implementing Large-Scale Demantra Table Rebuilds To Improve Performance with Zero Downtime Using DBMS_REDEFINITION

Greetings Demantra Users! There is an excellent note detailing Oracle's implementation of Demantra in a big data environment. This was Oracle's largest ever Internal value chain planning database table. Read about how we did this, implementing RDBMS partitions. See Implementing Large-Scale Demantra Table Rebuilds To Improve Performance with Zero Downtime (Doc ID 1587179.1)

Thursday Aug 02, 2012

Are you Implementing Partitions for Demantra? Consider These Points.

1) Partition columns must be a subset of the primary key columns

2) Each partition should have its own tablespace.  All partitions of a partitioned object must reside in tablespaces of a single block size.

3) Each of the large tables should have their own tablespace.

4) Set the following parameters so that the Analytical Engine can find the partition on which any combination resides:
  
    Parameter                Purpose
    PartitionColumnItem Specifies the name of the column that partitions the data by item.
 
    PartitionColumnLoc  Specifies the name of the column that partitions the data by location.

    Note: When the SALES_DATA table is not partitioned by a level column, you need to set:
    update init_params_0 set value_string = column name
    where pname in ('PartitionColumnItem', 'PartitionColumnLoc');


5) Compute the optimal PCTFREE, PCTUSED and INITRANS values for the tables.

6) Ensure that the Schema statistics are up to date.

7) When creating partitions, consider your main worksheet levels.  Does your primary key follow the worksheet levels?  Partitions should also follow your worksheet levels and primary key.  If you have several worksheets that have different levels, way your options according to use.

Also, please review the following MyOracleSupport Documents:

Oracle Demantra Implementing Partitions for Performance (Doc ID 1227173.1)
Demantra Performance Overview and Recommendations High Impact Discussion Points (Doc ID 1162795.1)
Partitioned Sales_data Table But Engine Run Is Slower (Doc ID 1331482.1)

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