Bottleneck Analysis situations

While executing in a message processing region or a batch message processing region, a transaction may be blocked by contention for resources managed by IMS (as opposed to resources managed by z/OS). The individual execution states in this group show you when and where transactions are slowed down by resources managed by IMS.

IMS_Wait_QBLKS_IO

This exception triggers when the collector finds a transaction waiting for I/O to complete on the queue blocks dataset.

The formula is:
Bottleneck_Analysis_Detail.Description EQ ‘QBLKS I/O' AND Bottleneck_Analysis_Detail.Transaction_Count GT 0

IMS_Wait_SHMSG_IO

This exception triggers when the collector finds a transaction waiting for I/O on the short message (SHMSG) dataset.

The formula is:
Bottleneck_Analysis_Detail.Description EQ ‘SHMSG I/O' AND Bottleneck_Analysis_Detail.Transaction_Count GT 0

IMS_Wait_LGMSG_IO

This exception triggers when the collector finds a transaction waiting for I/O on the long message (LGMSG) dataset.

The formula is:
Bottleneck_Analysis_Detail.Description EQ ‘LGMSG I/O' AND Bottleneck_Analysis_Detail.Transaction_Count GT 0

IMS_Wait_PI

This exception triggers when the collector finds the application program processing the transaction IWAITing for a program isolation (PI) resource. Program isolation is the mechanism which allows databases to be simultaneously accessed and even updated by different users. A PI resource is essentially a DMB number to identify the physical database, and an RBA (relative byte address) to identify the physical block being held. When two programs attempt to access the same PI resource at the same time, one must wait.

The formula is:
Bottleneck_Analysis_Detail.Description EQ ‘PI Wait' AND Bottleneck_Analysis_Detail.Transaction_Count GT 0

IMS_Wait_IRLM

This exception triggers when the collector finds the application program executing inside a dependent region. The dependent region issued a request to the IRLM address space and was waiting for a response. This wait reason can appear when there is a database conflict or when IRLM is waiting for internal IRLM processing.

The formula is:
Bottleneck_Analysis_Detail.Description EQ ‘IRLM Wait' AND Bottleneck_Analysis_Detail.Transaction_Count GT 0

IMS_Wait_Sync_Point

This exception triggers when the collector finds a transaction waiting for I/O to complete as the result of synchronization (SYNC) point processing.

The formula is:
Bottleneck_Analysis_Detail.Description EQ ‘Sync Point Wait' AND Bottleneck_Analysis_Detail.Transaction_Count GT 0

IMS_Wait_IWAIT_in_Term

This exception triggers when the collector finds the application program processing the transaction IWAITing. It also found an indication that the application program was terminating. The collector could not attribute the status of the transaction to any of the states listed above.

The formula is:
Bottleneck_Analysis_Detail.Description EQ ‘IWAIT in Term' AND Bottleneck_Analysis_Detail.Transaction_Count GT 0