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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.
Choosing operator classes for indexesFor most situations, use the default operators that are defined for a secondary-access method. However, when you want to order the data in a different sequence or provide index support for a user-defined data type, you must extend an operator class.
Built-in B-tree operator classThe built-in secondary-access method (the generic B-tree) has a default operator class called btree_ops, which is defined in the sysopclasses system catalog table.
B-tree strategy functionsThe btree_ops operator class defines the names of strategy functions for the btree access method.

B-tree strategy functions

The btree_ops operator class defines the names of strategy functions for the btree access method.

The strategy functions that the btree_ops operator class defines are:

lessthan (<)
lessthanorequal (<=)
equal (=)
greaterthanorequal (>=)
greaterthan (>)

These strategy functions are all operator functions. That is, each function is associated with an operator symbol; in this case, with a relational-operator symbol. For more information about relational-operator functions, see the HCL OneDB™ User-Defined Routines and Data Types Developer's Guide.

When the query optimizer examines a query that contains a column, it checks to see if this column has a B-tree index defined on it. If such an index exists and if the query contains one of the relational operators that the btree_ops operator class supports, the optimizer can choose a B-tree index to execute the query.