Scenarios of P-Lock operations

Looking at a scenario can help you understand how P-Lock operations work.

The following figure shows a typical sequence of events for P-locking and P-lock negotiations between two members of a data sharing group.

Figure 1. P-lock operations between two members. The arrows indicate that the members are negotiating P-lock modes.
Begin figure summary. Member DB1G and DB2G opens a page set for reading and take a P-lock in S mode. Subsequent steps before DB1G releases the P-lock is GBP-dependent. Detailed description available.

The following figure shows what happens when a single updater remains.

Figure 2. P-lock operations when single updater remains. When the reader physically closes the page set, the updater does not remove the GBP-dependency immediately.
Begin figure summary. Member DB1G and DB2G opens a page set for reading and take a P-lock n S mode. DB2G releases the P-lock while still GBP-dependent. Detailed description available.