Record-level sharing (RLS) is a VSAM function, which enables VSAM data to be shared, with full update capability, between many applications running in many CICS regions.
RLS Mode Advantage
With RLS, CICS regions that share VSAM data sets can reside in one or more MVS™ images within an MVS parallel sysplex. RLS also provides some benefits when data sets are being shared between CICS regions and batch jobs.
If you open a file in RLS mode, locking takes place at the record level instead of the Control-Interval level, thus reducing the risk of deadlocks.
CICS supports record-level sharing (RLS) access to the Below Types of VSAM data set.
- Key sequenced data sets (KSDS). Note that if you are using KSDS, you cannot use the relative byte address (RBA) to access files.
- Entry sequenced data sets (ESDS). Note that although RLS access mode is permitted for entry sequenced data sets (ESDS), it is not recommended, as it can have a negative effect on the performance and availability of the data set when you are adding records. (See Performance aspects of VSAM record-level sharing ).
- Relative record data sets (RRDS), for both fixed and variable-length records.