Some database indexes are system defined, but some can
be defined by a system administrator to improve performance.
This section describes the relationship between database indexes
and performance of row-based view filtering queries.
- Indexes automatically defined by the IBM® Content
Manager system
- When a row-based filter is defined on a component type view, the
library server automatically tries to create a database index on the
column corresponding to the filter attribute. This index helps to
improve the performance for complex queries that are written against
a data model that uses row-based view filtering. The database system
can use the index to create a better access plan to execute a complex
query.
Example: If the Organization attribute is specified as a
filter attribute during creation of the user view MyJournal on the
item type Journal, a database index is created on the column corresponding
to the Organization attribute in the table of the base component type
for Journal.
An index is created on the filter attribute regardless
of whether the component type view in which this attribute exists
is a root view or one of the child views. Also, the library server
relies on the database system to determine whether an index can be
created. In some cases the index might not be created if an index
already exists, for example. To verify that an index was created on
the Organization filter attribute for Journal, for example, a system
administrator can open the IBM Content
Manager system administration client and look for
a listing of an index on the Organization attribute.
- Indexes that a system administrator can define to improve performance
- To improve performance of some wildcard queries on an IBM Content
Manager system that has filtered
views, a system administrator can define indexes on the following
columns in system tables:
- ICMSTITEMS001001.COMPONENTTYPEID
- ICMSTITEMVER001001.COMPONENTTYPEID
- ICMSTRI001001.SOURCECOMPTYPEID
For IBM Content
Manager user
component tables (ICMUT* tables) that have reference attributes, you
can create indexes on the RTARGETCOMPTYPEID column (for the SYSREFERENCEATTRS
reference attribute) or any ATTRXXXXX00110 columns
(for user-defined reference attributes), such that XXXXX is the attribute group ID of the reference attribute, for example,
01005.
