Contents
pg_visible_in_snapshot()
A function showing whether a transaction ID is visible in a snapshot
pg_visible_in_snapshot() is a system function determining whether a transaction ID is visible in a snapshot.
pg_visible_in_snapshot() was added in PostgreSQL 13.
Usage
pg_visible_in_snapshot (xid8,pg_snapshot) →boolean
pg_visible_in_snapshot() returns true if the specified transaction was completed before the snapshot was taken, otherwise false.
The specified transaction must not be a subtransaction.
pg_visible_in_snapshot() replaces txid_visible_in_snapshot().
Change history
- PostgreSQL 13
- added (commit 4c04be9b)
Examples
Usage example for pg_visible_in_snapshot():
postgres=# SELECT pg_current_snapshot(); pg_current_snapshot --------------------- 795:799:795,797 (1 row) postgres=# SELECT pg_visible_in_snapshot('794'::xid8, '795:799:795,797'); pg_visible_in_snapshot ------------------------ t (1 row) postgres=# SELECT pg_visible_in_snapshot('796'::xid8, '795:799:795,797'); pg_visible_in_snapshot ------------------------ t (1 row) postgres=# SELECT pg_visible_in_snapshot('797'::xid8, '795:799:795,797'); pg_visible_in_snapshot ------------------------ f (1 row) postgres=# SELECT pg_visible_in_snapshot('798'::xid8, '795:799:795,797'); pg_visible_in_snapshot ------------------------ t (1 row) postgres=# SELECT pg_visible_in_snapshot('799'::xid8, '795:799:795,797'); pg_visible_in_snapshot ------------------------ f (1 row)
References
- PostgreSQL documentation: Transaction ID and Snapshot Information Functions
