doc: clarify wording about phantom reads

Reported-by: [email protected]
Discussion: https://postgr.es/m/165222922369.669.10475917322916060899@wrigleys.postgresql.org

Backpatch-through: 10

diff --git a/doc/src/sgml/high-availability.sgml b/doc/src/sgml/high-availability.sgml
index 23f71e347c166b0acf9be88f8f7739091840ce9d..a524dfa8ca5aaab645d202dbd0154b2bf97540ef 100644 (file)
--- 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 23c5a2d1cb4498acc1f63a30237cdc4bcd2485b2..eab58a9b9ac37cbb15f80d3dedcd193d58424ef1 100644 (file)
--- 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.