[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[leafnode-list] Re: When is usexhdr useful in leafnode 2?
On Mon, 30 Jun 2014 13:47:16 +0100 Adam Funk <a24061@xxxxxxxxxxxxx> wrote:
>The man page for leafnode 2 says:
> usexhdr = 1
> fetchnews will usually use XOVER to retrieve header information
> from the remote server. Under special circumstances, it may be
> faster to have it use XHDR instead. This line will try to enforce
> XHDR, but fetchnews will still fall back to XOVER if you also want
> to use filters in a group or if you work with "delaybody" set
> (because in these cases it will always be faster to use XOVER).
>What are the mysterious "special circumstances"?
>I've just noticed the "config: usexhdr does not work together with
>filtering or delaybody mode" warning in my logs; my config file has
>"usexhdr = 1" under nntp.aioe.org, but not in any of the other
>upstream server configs, & I can't recall when or why I put it there!
One returns all headers and body for the specified MID(s), the other can return
specified fields only. (We're supposed not to use the X in the command names
One circumstance in which HDR might be quicker, is if you need to retrieve only
one header and your connection to the server is very slow. I think HDR may
make more work for the upstream server.
The HDR command can be used eg to extract the References header from a given
article and from that issue the OVER commend for each of the MIDs revealed;
useful if you want to reconstruct a thread. (Slrn seems to work that way to
reconstruct a thread - which it can do when connected to Leafnode 2 but not
with Leafnode 1 which doesn't support HDR).
| 8.3.2. Description
| The OVER command returns the contents of all the fields in the
| database for an article specified by message-id, or from a specified
| article or range of articles in the currently selected newsgroup.
| 8.5.2. Description
| The HDR command provides access to specific fields from an article
| specified by message-id, or from a specified article or range of
| articles in the currently selected newsgroup. It MAY take the
| information directly from the articles or from the overview database.
| In the case of headers, an implementation MAY restrict the use of
| this command to a specific list of headers or MAY allow it to be used
| with any header; it may behave differently when it is used with a
| message-id argument and when it is used with a range or no argument.
leafnode-list mailing list