z/OS DFSMStvs Planning and Operating Guide
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Using sequential or random access to a data set

z/OS DFSMStvs Planning and Operating Guide
SC23-6877-00

Skip-sequential processing is generally used to speed browsing when reading through a data set. VSAM locates the next record by reading through the lowest level index rather than repositioning from scratch. This method is faster if the records being retrieved are relatively close together, but not necessarily adjacent. It can have the opposite effect if they are far apart in a large data set. If you know the key to which you are positioning is much higher and there might be a long index scan, use the POINT request to reset your positioning.

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