PostgreSQL physical replication - internals, latest development and opportunities

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" summary

Primary and standby exchange WAL via WalSender and WAL receiver; WalSender reads WAL from disk and startup applies WAL files on standby. Recent changes: PG15 adds pre-fetch WAL data, PG16 fixes a standby startup crash, and PG17 plans allow WalSender to read WAL from buffers instead of always hitting files. Proposed improvements include sending WAL before local flush finishes (decoupling flush/apply), doing standby pre-processing so apply is faster, and exploring io_uring for networking to cut replication latency.

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" chapters (5)

1. 0:00Intro to speaker & topic
2. 2:41Replication terminology
3. 10:19How does physical replication work?
4. 16:29Recent improvements in physical replication
5. 18:38Opportunities for future improvements to physical replication

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