From 046fd4f364157fca85eadfddb0f0e8e5d7ceef26 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Tue, 31 Mar 2020 17:57:44 -0400 Subject: [PATCH] doc: clarify when row-level locks are released They are released just like table-level locks. Also clean up wording. (Uses wording "rolled back to".) Reported-by: me@sillymon.ch Discussion: https://postgr.es/m/158074944048.1095.4309647363871637715@wrigleys.postgresql.org Backpatch-through: 9.5 --- doc/src/sgml/mvcc.sgml | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml index f8c9655111..ecff9474c8 100644 --- a/doc/src/sgml/mvcc.sgml +++ b/doc/src/sgml/mvcc.sgml @@ -1039,7 +1039,7 @@ ERROR: could not serialize access due to read/write dependencies among transact - Once acquired, a lock is normally held till end of transaction. But if a + Once acquired, a lock is normally held until the end of the transaction. But if a lock is acquired after establishing a savepoint, the lock is released immediately if the savepoint is rolled back to. This is consistent with the principle that ROLLBACK cancels all effects of the @@ -1178,7 +1178,10 @@ ERROR: could not serialize access due to read/write dependencies among transact conflicting locks on the same row, even in different subtransactions; but other than that, two transactions can never hold conflicting locks on the same row. Row-level locks do not affect data querying; they - block only writers and lockers to the same row. + block only writers and lockers to the same + row. Row-level locks are released at transaction end or during + savepoint rollback, just like table-level locks. +