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authorJoe Conway <mail@joeconway.com>2019-02-17 13:15:14 -0500
committerJoe Conway <mail@joeconway.com>2019-02-17 13:17:34 -0500
commitbc6d7eb689a2d083df981dfd10c65d1a9d32ca64 (patch)
tree10994f6d6cb92ee7ace23c15aa477a10b07b68c4
parenta32ca7883629f6b1fbbf0bd2e2aa11ec86edb6b3 (diff)
downloadpostgresql-bc6d7eb689a2d083df981dfd10c65d1a9d32ca64.tar.gz
postgresql-bc6d7eb689a2d083df981dfd10c65d1a9d32ca64.zip
Fix documentation for dblink_error_message() return value
The dblink documentation claims that an empty string is returned if there has been no error, however OK is actually returned in that case. Also, clarify that an async error may not be seen unless dblink_is_busy() or dblink_get_result() have been called first. Backpatch to all supported branches. Reported-by: realyota Backpatch-through: 9.4 Discussion: https://postgr.es/m/153371978486.1298.2091761143788088262@wrigleys.postgresql.org
-rw-r--r--doc/src/sgml/dblink.sgml16
1 files changed, 15 insertions, 1 deletions
diff --git a/doc/src/sgml/dblink.sgml b/doc/src/sgml/dblink.sgml
index 87e14ea093d..97dc3b81292 100644
--- a/doc/src/sgml/dblink.sgml
+++ b/doc/src/sgml/dblink.sgml
@@ -1165,12 +1165,26 @@ dblink_error_message(text connname) returns text
<title>Return Value</title>
<para>
- Returns last error message, or an empty string if there has been
+ Returns last error message, or <literal>OK</literal> if there has been
no error in this connection.
</para>
</refsect1>
<refsect1>
+ <title>Notes</title>
+
+ <para>
+ When asynchronous queries are initiated by
+ <function>dblink_send_query</function>, the error message associated with
+ the connection might not get updated until the server's response message
+ is consumed. This typically means that <function>dblink_is_busy</function>
+ or <function>dblink_get_result</function> should be called prior to
+ <function>dblink_error_message</function>, so that any error generated by
+ the asynchronous query will be visible.
+ </para>
+ </refsect1>
+
+ <refsect1>
<title>Examples</title>
<programlisting>