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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.
Effect of configuration on I/O activityThe configuration of your database server affects I/O activity.
Table I/OOne of the most frequent functions that the database server performs is to bring data and index pages from disk into memory. Pages can be read individually for brief transactions and sequentially for some queries. You can configure the number of pages that the database server brings into memory, and you can configure the timing of I/O requests for sequential scans.
Unavailable dataAnother aspect of table I/O pertains to situations in which a query requests access to a table or fragment in a dbspace that is temporarily unavailable. When the database server determines that a dbspace is unavailable as the result of a disk failure, queries directed to that dbspace fail by default. The database server allows you to specify dbspaces that, when unavailable, can be skipped by queries,

Unavailable data

Another aspect of table I/O pertains to situations in which a query requests access to a table or fragment in a dbspace that is temporarily unavailable. When the database server determines that a dbspace is unavailable as the result of a disk failure, queries directed to that dbspace fail by default. The database server allows you to specify dbspaces that, when unavailable, can be skipped by queries,

For information about specifying dbspaces that, when unavailable, can be skipped by queries, see How DATASKIP affects table I/O.

Warning: If a dbspace containing data that a query requests is listed in the DATASKIP configuration parameter and is currently unavailable because of a disk failure, the data that the database server returns to the query can be inconsistent with the actual contents of the database.

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