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help / color / mirror / Atom feedFrom: Joe Conway <[email protected]>
To: Tom Lane <[email protected]>
To: [email protected]
Cc: [email protected]
Subject: Re: dblink_error_message return value
Date: Tue, 25 Sep 2018 15:58:12 -0400
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
<[email protected]>
On 09/25/2018 01:50 PM, Joe Conway wrote:
> On 08/08/2018 11:57 AM, Tom Lane wrote:
>> =?utf-8?q?PG_Doc_comments_form?= <[email protected]> writes:
>>> The following documentation comment has been logged on the website:
>>> Documentation says:
>>
>>> Return Value
>>> Returns last error message, or an empty string if there has been no error in
>>> this connection.
>>> Which is invalid.
>>> Actually it returns 'OK' string if no error was raised.
>>
>> Good catch! The code's quite clear about it, but the SGML docs need
>> fixed.
>
>
> As mentioned on the nearby thread, will fix. I suppose this ought to be
> back-patched.
>
>
>>> Secondly
>>> dblink_is_busy must be first called to make dblink_error_message returns an
>>> error message. (Tested on 9.6.9)
>>
>> Meh. I see what you're getting at here, I think, but that seems like a
>> completely wrong/misleading statement of the issue. Joe, can you think of
>> better phraseology?
>
> Maybe a note, something like this?
> ------------
> When asynchronous queries are initiated by dblink_send_query(), the
> error message associated with the connection might not get updated until
> the server's response message is consumed. This typically means that
> dblink_is_busy() or dblink_get_result() should be called prior to
> dblink_error_message(), so that any error generated by the asynchronous
> query() will be visible.
> ------------
And now with the corresponding patch attached.
Thoughts/comments?
Joe
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Attachments:
[text/x-patch] doc-dblink_error_message-01.patch (1.3K, 2-doc-dblink_error_message-01.patch)
download | inline diff:
diff --git a/doc/src/sgml/dblink.sgml b/doc/src/sgml/dblink.sgml
index 87e14ea..97dc3b8 100644
*** a/doc/src/sgml/dblink.sgml
--- b/doc/src/sgml/dblink.sgml
*************** dblink_error_message(text connname) retu
*** 1165,1175 ****
<title>Return Value</title>
<para>
! Returns last error message, or an empty string if there has been
no error in this connection.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
--- 1165,1189 ----
<title>Return Value</title>
<para>
! 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>
[application/pgp-signature] signature.asc (819B, 3-signature.asc)
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