OBA=nnnn parameter for procedures
Use the OBA=nnnn parameter in procedure to specify a 4-digit number of additional page-fixed buffers to be made available to a Fast Path application region if the normal allotment is used. The default is 0.
If you are using the Fast Path 64-bit buffer manager, the buffer pools are loaded there. Otherwise, they are loaded in the 31-bit common storage area. In the common storage area, the system page fixes only enough additional buffers to handle the largest overflow specification from all active regions.
When the Fast Path 64-bit buffer mode is used, a BMP can use the DEF_OBA parameter of the FASTPATH section. You can specify a value of 1 - 9999. If you specify a value greater than 9999, the 64-bit buffer mode is turned off. You must restart IMS after you change the value to a valid number.
To prevent a situation in which every program is waiting for buffers when no buffers are available, the system allows only one program at a time to use its overflow allocation. If an application needs more buffers than the combined values of NBA and OBA, it abnormally ends (for message-driven programs) or an FR status code is issued (for non-message-driven programs).
When the 64-bit buffer manager is used, the use of OBA buffers is not serialized. Multiple dependent regions or threads might be using their OBA allocations at the same time, which eliminates a potential bottleneck in buffer use. In practice, it means that each region or thread might be using the number of buffers equal to the combined values of the NBA and OBA specifications.