doc: improve text around consistency of statistics values

Discussion: https://postgr.es/m/CAKFQuwZ4CXtTyR19vFbd9WwmW-4BvgAenmF2CfUpx0LWwRPGYg@mail.gmail.com

Author: David G. Johnston

Backpatch-through: master

diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 9389eef973d081ef3eff586c768d887082df0513..2bfa05b8bc02c09d3fa6392a96b44cd9407d6015 100644 (file)
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -924,10 +924,9 @@ vacuum insert threshold = vacuum base insert threshold + vacuum insert scale fac
      as this may allow
     tuples to be frozen by earlier vacuums.  The number of obsolete tuples and
     the number of inserted tuples are obtained from the cumulative statistics system;
-    it is a semi-accurate count updated by each UPDATE,
-    DELETE and INSERT operation.  (It is
-    only semi-accurate because some information might be lost under heavy
-    load.)  If the relfrozenxid value of the table
+    it is an eventually-consistent count updated by each UPDATE,
+    DELETE and INSERT operation.
+    If the relfrozenxid value of the table
     is more than vacuum_freeze_table_age transactions old,
     an aggressive vacuum is performed to freeze old tuples and advance
     relfrozenxid; otherwise, only pages that have been modified