diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index e138d1ef07..82c015806e 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -1068,7 +1068,7 @@ postgres 27093 0.0 0.0 30096 2752 ? Ss 11:34 0:00 postgres: ser
oldserxid
- Waiting to I/O on an oldserxid buffer.
+ Waiting for I/O on an oldserxid buffer.
wal_insert