Incremental Update Sequencing

Incremental Update Sequencing is the management of the chronological order of market data updates to ensure the local state reflects the true evolution of the order book. Each update from an exchange usually includes a sequence number; the client must process these in exact order to avoid state corruption.

If an update is received out of order or a sequence number is skipped, the local state becomes invalid and requires a full re-sync. This sequencing is vital for maintaining the integrity of L2 data.

High-performance systems use specialized data structures to buffer and reorder incoming packets if necessary, though the goal is always to process them in real-time. This is a foundational aspect of order book data engineering.