Transaction boundaries and replay at scale

A system for bounding transactions, the system comprising:

• one or more processors;
• and
• at least one memory coupled to the one or more processors and storing instructions that, when executed by the one or more processors, cause the system to perform operations including:
• obtaining, at a source component, a set of change events, each change event associated with one of a plurality of unique identifiers and one of a plurality of transactions, wherein the obtaining includes extracting the set of change events from a source database, and wherein the source database is one of a plurality of source databases managed by a database management system (DBMS) serving a plurality of source applications;
• partitioning, using the source component, the set of change events into a plurality of partitions of a staging queue based on the unique identifiers;
• and
• generating, using a distributed sink component that parallelly processes the set of change events from the staging queue, a bounded list indicating, for each respective transaction processed for each partition, a start boundary for the respective transaction, the change events associated with the respective transaction, and an end boundary for the respective transaction.