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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 Informix® database servers.
Performance GuideThe Informix® Performance Guide describes how to configure and operate your HCL Informix® 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 smart large objects in sbspaces When you create a table, you should use the extent size that the database server calculates for smart large objects in sbspaces. Alternatively, you can use the final size of the smart large object, as indicated by a particular function when you open the sbspace in an application program.

Extent sizes for smart large objects in sbspaces

When you create a table, you should use the extent size that the database server calculates for smart large objects in sbspaces. Alternatively, you can use the final size of the smart large object, as indicated by a particular function when you open the sbspace in an application program.

You can use the final size of the smart large object when you open one of the following application programs:

For DB-Access: Use the DataBlade® API mi_lo_specset_estbytes function. For more information about the DataBlade API functions to open a smart large object and set the estimated number of bytes, see the Informix® DataBlade API Programmer's Guide.
For ESQL/C: Use the Informix ESQL/C ifx_lo_specset_estbytes function. For more information about the Informix ESQL/C functions to open a smart large object and set the estimated number of bytes, see the Informix ESQL/C Programmer's Manual.

For more information about sizing extents, see Sbspace extents. For more information, see Monitoring sbspaces.

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