CICS threadsafe commands in the SPI

If you write and define a CICS program as threadsafe, it can receive control on an open transaction environment (OTE) TCB.

To obtain the maximum performance benefit from OTE, write your CICS programs in a threadsafe manner to avoid CICS having to switch TCBs. However, be aware that not all EXEC CICS commands are threadsafe, and issuing any of the non-threadsafe commands causes CICS to switch your task back to the QR TCB to ensure serialization. The commands that are threadsafe are indicated in the command syntax diagrams in this programming reference with the statement: "This command is threadsafe".

For a list of the system programming interface (SPI) commands that are threadsafe, see Threadsafe SPI commands.

For similar statements about the application programming interface (API), see CICS threadsafe commands in the API.