no_wait

This method instructs the DSI to initiate the next transaction without waiting for the previous transaction to commit. It assumes that your primary applications are designed to avoid conflicting updates, or that dsi_partitioning_rule is used effectively to reduce or eliminate contention. Adaptive Server does not hold update locks unless dsi_isolation_level has been set to 3. The method assumes little contention between parallel transactions and results in the nearly parallel execution shown in Figure 4-6.

Figure 4-4: Thread timing with the no_wait serialization method

Figure 4-4 illustrates the thread timing with no underscore wait serialization method. The figure shows three transactions, A, B, and C, where in transaction B was initiated without waiting for transaction A to commit. The same goes with transaction C, without waiting for it to commit, transaction A has been initiated.

no_wait provides the better opportunity for increased performance, but also provides the greater risk of creating contentions.