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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.
Managing extentsAs you add rows to a table, the database server allocates disk space in units called extents. Each extent is a block of physically contiguous pages from the dbspace. Even when the dbspace includes more than one chunk, each extent is allocated entirely within a single chunk, so that it remains contiguous.
Choosing table extent sizesWhen you create a table, you can specify extent sizes for the data rows of a table in a dbspace and for each fragment of a fragmented table, and the smart large objects in an sbspace. The database server calculates extent sizes for smart large objects in sbspaces.
Extent sizes for table fragmentsWhen you fragment an existing table, you might want to adjust the next-extent size because each fragment requires less space than the original, unfragmented table.

Extent sizes for table fragments

When you fragment an existing table, you might want to adjust the next-extent size because each fragment requires less space than the original, unfragmented table.

If the unfragmented table was defined with a large next-extent size, the database server uses that same size for the next-extent on each fragment, which results in over-allocation of disk space. Each fragment requires only a proportion of the space for the entire table.

For example, if you fragment the preceding big_one sample table across five disks, you can alter the next-extent size to one-fifth the original size. The following example changes the next-extent size to one-fifth of the original size:

ALTER TABLE big_one MODIFY NEXT SIZE 2;