From 3485f8d03eb8cdaa1100472fd36761b1a4b82337 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Wed, 22 Jun 2022 14:33:26 -0400 Subject: [PATCH] doc: clarify wording about phantom reads Reported-by: akhilhello@gmail.com Discussion: https://postgr.es/m/165222922369.669.10475917322916060899@wrigleys.postgresql.org Backpatch-through: 10 --- doc/src/sgml/high-availability.sgml | 2 +- doc/src/sgml/mvcc.sgml | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml index 23f71e347c..a524dfa8ca 100644 --- a/doc/src/sgml/high-availability.sgml +++ b/doc/src/sgml/high-availability.sgml @@ -2345,7 +2345,7 @@ LOG: database system is ready to accept read only connections Currently, temporary table creation is not allowed during read only transactions, so in some cases existing scripts will not run correctly. This restriction might be relaxed in a later release. This is - both a SQL Standard compliance issue and a technical issue. + both a SQL standard compliance issue and a technical issue. diff --git a/doc/src/sgml/mvcc.sgml b/doc/src/sgml/mvcc.sgml index 23c5a2d1cb..eab58a9b9a 100644 --- a/doc/src/sgml/mvcc.sgml +++ b/doc/src/sgml/mvcc.sgml @@ -277,9 +277,10 @@ The table also shows that PostgreSQL's Repeatable Read implementation - does not allow phantom reads. Stricter behavior is permitted by the - SQL standard: the four isolation levels only define which phenomena - must not happen, not which phenomena must happen. + does not allow phantom reads. This is acceptable under the SQL + standard because the standard specifies which anomalies must + not occur at certain isolation levels; higher + guarantees are acceptable. The behavior of the available isolation levels is detailed in the following subsections.