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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.
High-Performance Loader User's GuideThe describes how to use the HCL Informix® to load and unload large quantities of data efficiently to or from Informix® databases.
Manage the High-Performance Loader
HPL performanceYou can improve the HPL performance by preparing an environment that is optimized for the particular load or unload job that you are performing.
Settings for a no-conversion load or unload jobA no-conversion load or unload is not highly CPU intensive because no conversion is involved. In this case, the load or unload is expected to be limited by the speed of the tape devices. No-conversion loads and unloads are always completed in express mode.
Run no-conversion load jobs with tables with hidden columnsIf you run no-conversion jobs, the physical image of the table in the load file must match the physical image of the target table and all columns must exist in the same order and be of the same type.

Run no-conversion load jobs with tables with hidden columns

If you run no-conversion jobs, the physical image of the table in the load file must match the physical image of the target table and all columns must exist in the same order and be of the same type.

By default a no-conversion unload job does not contain the hidden columns, because the job resulted from unloading a "SELECT *" query and this type of SELECT query does not return any hidden columns. Under these circumstances, the target table where the load will occur must not contain any hidden columns. If it does contain hidden columns, the image of the file will not be a match.

If your application requires that the unload file contains the hidden columns (for example, if the target table has hidden columns and it is not possible to alter the table to remove the columns while the load occurs) , you must use a SELECT statement that explicitly indicates the columns in the select list.

The target table should not contain hidden columns, because these columns retain internal information for internal activities of the engine. Loading hidden columns can create unexpected results.

Hidden columns tables include but are not restricted to fragmented tables with rowid columns, tables with VERCOLS, and tables with CRCOLS. Also fragmented tables with rowid columns do not support no-conversion jobs.

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