FCQRONLY
The FCQRONLY system initialization parameter specifies whether you want CICS to force all file control requests to run under the CICS QR TCB. This parameter applies to file control requests that access VSAM RLS files and local VSAM LSR files. Requests for all other file types always run on the QR TCB.
- FCQRONLY={YES|NO}
- Valid values are as follows:
- NO
- File Control requests are treated as threadsafe and are run on an open TCB to avoid unnecessary TCB switching. For CONCURRENCY(REQUIRED) programs the request runs on an open TCB. For CONCURRENCY(THREADSAFE) programs the request runs on whatever TCB is being used at the time of the request.
- YES
- File control requests are treated as non-threadsafe. CICS forces
all file control requests to run under the CICS QR TCB. With all file
requests on the QR TCB, CICS can minimize the amount of locking required
at the expense of additional TCB switches if requests are run on
open TCBs. YES is the default.
For a program defined as CONCURRENCY(REQUIRED), if the file control request is run under the CICS QR TCB, CICS switches back to the open TCB before handing control back to the application program.
For file-owning regions (FORs), choose an appropriate setting for FCQRONLY:- For FORs where the connections to that region are primarily MRO or ISC connections, these requests run on the QR TCB, and CICS runs the mirror program primarily on the QR TCB. Specify FCQRONLY=YES so that all file control requests are processed on the QR TCB. This setting improves performance by avoiding locking, which is unnecessary when all file control requests run on the same TCB.
- For FORs where the connections to that region are primarily IPIC connections, these requests run on open TCBs, and CICS runs the mirror program on an L8 open TCB whenever possible. Specify FCQRONLY=NO so that file control requests do not switch to the QR TCB to be processed. This setting improves performance by multi-threading file control requests.