diff --git a/doc/src/sgml/ref/pg_rewind.sgml b/doc/src/sgml/ref/pg_rewind.sgml
index d5430d4..bcd094b 100644
--- a/doc/src/sgml/ref/pg_rewind.sgml
+++ b/doc/src/sgml/ref/pg_rewind.sgml
@@ -50,9 +50,12 @@ PostgreSQL documentation
<para>
The result is equivalent to replacing the target data directory with the
source one. Only changed blocks from relation files are copied;
- all other files are copied in full, including configuration files. The
- advantage of <application>pg_rewind</> over taking a new base backup, or
- tools like <application>rsync</>, is that <application>pg_rewind</> does
+ all other files except WAL are copied in full, including configuration
+ files. Only the WAL files between the point of divergence and the current
+ WAL insert location of the source server are copied, for other WAL files
+ are useless for the target server. The advantage of
+ <application>pg_rewind</> over taking a new base backup, or tools
+ like <application>rsync</>, is that <application>pg_rewind</> does
not require reading through unchanged blocks in the cluster. This makes
it a lot faster when the database is large and only a small
fraction of blocks differ between the clusters.
@@ -231,7 +234,7 @@ PostgreSQL documentation
<para>
Copy all other files such as <filename>pg_xact</filename> and
configuration files from the source cluster to the target cluster
- (everything except the relation files).
+ (everything except the relation files and some WAL files).
</para>
</step>
<step>
------
Best Regars,
Chen Huajun