VSAM Performance Enhancement › Advanced Topics › VPE Implementation Considerations › Sequentially Accessed VSAM Files

Sequentially Accessed VSAM Files

If a VSAM file has a high RBA of 0 (that is, the file is empty), has only one record in it, or if the ACB opened for the file has sequential processing specified, VPE assumes the file is in a load state. A buffer space target is created such that full track read/write operations are performed for the data portion of the file and each index level has an index buffer. It is possible some applications load these files and then update them. If the update is large, use the VPE rule statement FORCEMODE=LSR to speed these jobs up more than the default sequential buffering.