Postgres Concurrency - Explain XID Wraparound - Reusing a Previously Used XID

PostgreSQL’s transaction IDs (XIDs) are 32-bit unsigned integers and eventually wrap around after about 4 billion transactions.

Explain XID Wraparound - Reusing a Previously Used XID

PostgreSQL’s transaction IDs (XIDs) are 32-bit unsigned integers and eventually wrap around after about 4 billion transactions. When this wraparound happens, PostgreSQL must distinguish between:

• Old transaction from the previous era ( with the same XID number but far in the past )

• Current or recent tra…