Regular Workflows versus In-Memory Workflows

In-memory workflows provide almost double the throughput as compared to regular workflows. Moreover, this gap widens as more and more data accumulates, regular workflows get slower unless you purge history regularly.

Regular Workflows versus In-Memory Workflows
Regular Workflows In-Memory Workflows
During each activity execution, process states are persisted to database and distributed cache. During each activity execution, process states are written to the local cache.
Input, output, and intermediate documents are persisted to the file system. Input, output, and intermediate documents are maintained in the local cache.
Each activity is considered a transaction. The entire workflow (consisting of multiple activities) is considered a transaction.
When a transaction is committed, all workflow changes (process states, documents, record related data) in that activity are committed. When a transaction is committed, record related data in the workflow is committed. If the saveonsuccess parameter is on, data from the local cache (process states, documents) is committed.