From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Fri, 28 Nov 2014 21:06:18 +0000 (-0300)
Subject: Update transaction README for persistent multixacts
X-Git-Tag: REL9_5_ALPHA1~1131
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=ae04bf50277ae25ca741cf3322d231c7dfb4c997;p=postgresql

Update transaction README for persistent multixacts

Multixacts are now maintained during recovery, but the README didn't get
the memo.  Backpatch to 9.3, where the divergence was introduced.
---

diff --git a/src/backend/access/transam/README b/src/backend/access/transam/README
index ba6ae05d65..b619de5ad3 100644
--- a/src/backend/access/transam/README
+++ b/src/backend/access/transam/README
@@ -840,10 +840,7 @@ parent transaction to complete.
 
 Not all transactional behaviour is emulated, for example we do not insert
 a transaction entry into the lock table, nor do we maintain the transaction
-stack in memory. Clog entries are made normally. Multixact is not maintained
-because its purpose is to record tuple level locks that an application has
-requested to prevent other tuple locks. Since tuple locks cannot be obtained at
-all, there is never any conflict and so there is no reason to update multixact.
+stack in memory. Clog and multixact entries are made normally.
 Subtrans is maintained during recovery but the details of the transaction
 tree are ignored and all subtransactions reference the top-level TransactionId
 directly. Since commit is atomic this provides correct lock wait behaviour