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AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
System administrationThese topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL OneDB™ database servers.
Performance GuideThe HCL OneDB™ Performance Guide describes how to configure and operate your HCL OneDB™ database server to improve overall system throughput and to improve the performance of SQL queries.
Indexes and index performance considerationsHCL OneDB™ provides several types of indexes. Some performance issues are associated with indexes.
Indexes on user-defined data typesYou can define your own data types and the functions that operate on these data types. You can define indexes on some kinds of user-defined data types.
Defining indexes for user-defined data typesAs with built-in data types, you might improve the response time for a query when you define indexes for new data types.
Using a functional indexYou can create a column index on the actual values in one or more columns. You can also create a functional index on the values of one or more columns that a user-defined function returns from arguments.
What is a functional index?A functional index can be a B-tree index, an R-tree index, or a user-defined index type that a DataBlade® module provides.

What is a functional index?

A functional index can be a B-tree index, an R-tree index, or a user-defined index type that a DataBlade® module provides.

When you create a functional index, the database server computes the values of the user-defined function and stores them as key values in the index. When a change in the table data causes a change in one of the values of an index key, the database server automatically updates the functional index.

You can use a functional index for functions that return values of both user-defined data types (opaque and distinct) and built-in data types. However, you cannot define a functional index if the function returns a simple-large-object data type (TEXT or BYTE).

For more information about the types of indexes, see Defining indexes for user-defined data types. For information about space requirements for functional indexes, see Estimating index pages.