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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.
Table performance considerationsSome performance issues are associated with unfragmented tables and table fragments.
Changing tables to improve performanceYou can change tables to improve performance by dropping indexes, attaching or detaching fragments, and altering table definitions. You can also create databases for decision-support applications by unloading and loading tables in OLTP databases.
Altering a table definitionThe database server uses one of these algorithms to process an ALTER TABLE statement in SQL: slow alter, in-place alter, or fast alter.
Fast alter The database server uses the fast alter algorithm when the ALTER TABLE statement changes attributes of the table but does not affect the data.

Fast alter

The database server uses the fast alter algorithm when the ALTER TABLE statement changes attributes of the table but does not affect the data.

The database server uses the fast alter algorithm when you use the ALTER TABLE statement to:

Change the next-extent size.
Add or drop a constraint.
Change the lock mode of the table.
Change the unique index attribute without modifying the column type.
Add shadow columns for row versioning with the ADD VERCOLS keywords.

With the fast alter algorithm, the database server holds the lock on the table for just a short time. In some cases, the database server locks the system catalog tables only to change the attribute. In either case, the table is unavailable for queries for only a short time.