Performance Tuning Guide - EMC Community Network

Designing the Application
Changing the default date attribute for sorting a task list
Task list queries that use filtering and sorting against large database tables (many users and work
items) perform poorly. By default, TaskSpace stores the data, against which filtering and sorting
queries get executed, in different database tables. The performance impact can be due to the database
spending resources on evaluating the sort instead of using an index (indexes do not span multiple
tables).
Collect the database execution plan and note the sort query performance against the default queue
item date_sent. If it performs poorly, use Forms Builder to modify the task list form to sort on the
work item creation date, which is in the same data table as the default filter criteria. Validate that this
change makes a substantive improvement by rerunning the database execution plan.
Using task history (audit trail)
Task histories provide a list of actions that were performed on items in a task list before the user
received the task. TaskSpace queries the audit trail database table for task history metadata. The
audit trail database table can often grow to be large. As a result, the queries for task histories can
have a significant performance impact.
The following provides a DQL example used to populate a task history:
select workflow_id from dm_audittrail where event_source = 'workflow' and
event_name = 'dm_wf_invoke_subprocess' and id_5 = '4d99f81680014546'
which is then translated into this SQL:
select all dm_audittrail.workflow_id from dm_audittrail_sp dm_audittrail
where ((dm_audittrail.event_source=N'workflow') and
(dm_audittrail.event_name=N'dm_wf_invoke_subprocess') and
(dm_audittrail.id_5=N'4d99f81680014546'))
The following index was applied to the table in order for the query to perform:
dm_audittrail_s(id_5,event_name,event_source)
The audit trail query could grow to 2 million rows, where it would have a major impact on
performance. As a general guideline:
• Avoid using task histories unless they are essential.
• If you use task histories, maintain the audit trail tables by purging or archiving database table
rows.
• Expand the dm_audittrail database table to a couple million rows to see how it impacts
performance.
Embedding documents (document viewing)
Task forms containing embedded document (for viewing) typically add 2-3 seconds in total rendering
time. When designed incorrectly, rendering time can become much longer (more than 10 seconds).
Document Image Services (DIS), in combination with Accelerated Content Services (ACS) and Branch
Office Caching Services (BOCS), enable page serving for certain document formats with particular
document viewers. See the Document Image Services Deployment Guide and TaskSpace Deployment
EMC Documentum xCP 1.0 Performance Tuning Guide 51