Product Documentation

FairCom ISAM for C

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Disable Key Buffer Support for Faster ISAM Access

By suppressing the evaluation of all ISAM keys, ISAM record retrieval performance can be enhanced. For each user, each ISAM data file is assigned a set of key buffers containing the current key image of each index for the current ISAM position. To speed record access, UpdateHeader() accepts a mode, ctISAMKBUFhdr, which toggles support of the key buffers for a particular ISAM data file for the calling user.

Key buffer support is enabled/disabled with UpdateHeader() as shown in the sections below:

Several considerations apply.