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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.
Monitoring the upper limit on extents and extent interleavingYou can monitor the upper limit on the number of extents. You can also check for and eliminate extent interleaving.
Considering the upper limit on extentsDo not allow a table to acquire a large number of extents because an upper limit exists on the number of extents allowed. Trying to add an extent after you reach the limit causes error -136 (No more extents) to follow an INSERT request.

Considering the upper limit on extents

Do not allow a table to acquire a large number of extents because an upper limit exists on the number of extents allowed. Trying to add an extent after you reach the limit causes error -136 (No more extents) to follow an INSERT request.

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To help ensure that the limit is not exceeded, the database server performs the following actions:

The database server checks the number of extents each time that it creates an extent. If the number of the extent being created is a multiple of 16, the database server automatically doubles the next-extent size for the table. Therefore, at every 16th creation, the database server doubles the next-extent size.
When the database server creates an extent next to the previous extent, it treats both extents as a single extent.

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