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PeopleSoft Temporary Records

Resetting High Water Marks on On-line Temporary Table Instances

PeopleSoft has always used regular database tables for temporary working storage in batch processes.   Up to PeopleTools 7.x working storage tables were shared by all instances of a program.  That led to consistent read contention when multiple processes concurrently used the same table, resulting in much higher high water marks that increased durations of full scans.
From PeopleTools 8, many copies of each temporary working storage table are created.  Application Engines that run on the Process Scheduler are allocated exclusive use of a particular copy of the table.  This avoids the inter-process contention.  They start by truncating each allocated table, which resets the high-water mark.

Unlocking Temporary Table Instances from Deleted Process Requests

In a previous blog entry, I discussed how to detect whether an Application Engine process had run out of non-shared Temporary Table instances by querying the message log table for the entries written when this happens.

This can happen because processes that have locked all available non-shared table instances are currently processing. However, if a restartable Application Engine program terminates with an error, the tables remain locked to that process instance so that it can be restarted. If that process instance is neither cancelled nor restarted so that it subsequently runs to success then the tables will remain locked, and in time the Process Scheduler archive process may purge the process request record.

Unlocking Temporary Table Instances from Deleted Process Requests

In a previous blog entry, I discussed how to detect whether an Application Engine process had run out of non-shared Temporary Table instances by querying the message log table for the entries written when this happens.

This can happen because processes that have locked all available non-shared table instances are currently processing. However, if a restartable Application Engine program terminates with an error, the tables remain locked to that process instance so that it can be restarted. If that process instance is neither cancelled nor restarted so that it subsequently runs to success then the tables will remain locked, and in time the Process Scheduler archive process may purge the process request record.

UKOUG PeopleSoft Conference 2009 Presentations

The 2009 conference is past, but the agenda is still available on the UKOUG webiste, and if you are a UKOUG member or attended the conference, you can download the presentations.

I will be gave two new presentations that are on my website.

UKOUG PeopleSoft Conference 2009 Presentations

The 2009 conference is past, but the agenda is still available on the UKOUG webiste, and if you are a UKOUG member or attended the conference, you can download the presentations.

I will be gave two new presentations that are on my website.

Statistics Management for PeopleSoft Temporary Records in Application Engine Programs

Last year, I wrote about Oracle Optimizer Statistics and Optimizer Dynamic Sampling with PeopleSoft Temprorary Records. Earlier this year, I encountered a situation where Optimizer Dynamic Sampling was not sufficient, and I did need properly gathered statistics on an object. I modified my PL/SQL packaged procedure wrapper which can be called by the %UpdateStats PeopleCode macro via a customised DDL model to collects statistics.

I still recommend locking statistics on PeopleSoft Temporary Record, so that table is omitted from schema or database wide operations to refresh statistics. If the statistics on a table are locked, and it is not a Global Temporary Table, then the wrapper package will force collection and update of statistics on the table (previously it suppressed gathering of statistics on tables with locked statistics).

However, when the Application Engine program completes, any statistics collected on those temporary tables are no longer needed. Worse, the statistics refer to data that will be deleted and replaced by some future program, and if the table were not reanalysed, the statistics would be misleading, and could cause the database to produce an inappropriate execution plan. Some temporary records are shared by multiple programs, so you cannot guarantee that statistics will always be refreshed when the table is next used.

Statistics Management for PeopleSoft Temporary Records in Application Engine Programs

Last year, I wrote about Oracle Optimizer Statistics and Optimizer Dynamic Sampling with PeopleSoft Temprorary Records. Earlier this year, I encountered a situation where Optimizer Dynamic Sampling was not sufficient, and I did need properly gathered statistics on an object. I modified my PL/SQL packaged procedure wrapper which can be called by the %UpdateStats PeopleCode macro via a customised DDL model to collects statistics.

I still recommend locking statistics on PeopleSoft Temporary Record, so that table is omitted from schema or database wide operations to refresh statistics. If the statistics on a table are locked, and it is not a Global Temporary Table, then the wrapper package will force collection and update of statistics on the table (previously it suppressed gathering of statistics on tables with locked statistics).

However, when the Application Engine program completes, any statistics collected on those temporary tables are no longer needed. Worse, the statistics refer to data that will be deleted and replaced by some future program, and if the table were not reanalysed, the statistics would be misleading, and could cause the database to produce an inappropriate execution plan. Some temporary records are shared by multiple programs, so you cannot guarantee that statistics will always be refreshed when the table is next used.