[tex-live] Errors messages installing/updating TL2013

[Zdenek Wagner]

2013/7/13 Angelo Graziosi <angelo.graziosi at alice.it>:
> Il 13/07/2013 0.17, Karl Berry ha scritto:
>
>>      angelo> It is *exactly* what I have seen
>>
>> You say *exactly*, but the error message George reports is different
>> from the one you reported.  It can make a difference, although I
>
>
> They seem of the same nature to me:
>
>   TLDownload::get_file: response error: 500 Can't use...
>
>   TLDownload::get_file: response error: 500 Can't locate...
>
>
> and I have reported a short example of the messages produced..
>
> "Exactly" was to stress that running the same command a second time, doesn't
> produce those messages and "tlmgr ... --all" produces those messages almost
> for every updating package. Anyway the upgrade was completed (wget fallback)
> successfully.
>
If a network is employed, you can never do exactly the same. You would
have to ask the whole world to behave exactly the same way and you
will have to reset cache of all web servers, transparent proxies, dns
servers and routers to the exact equal state which is impossible (you
can restart any server or router but there is no tool to set its cache
to an older state). Thus the response of the network will always be
different. If the response time is near te timeout value, it may
sometimes succeed and sometimes fail and the result will not be
reproducible. Norbert knows the details but if I understand it well,
tlmgr keeps already downloaded packages and if update fails and is
restarted later, tlmgr can check the version number or in case of http
it is also possible to use If-Modified-Since or ETag headers in order
not to download a file if a fresh copy is available.

If you look at RFC's dealing with the http protocol, you will see that
there are several methods how to download many files from a single
server. The faster methods may be less reliable so tlmgr is able to
use the slow method if the fast method does not work.

> Probably it is a mirror/connection issue. For example, today I have updated
> adding --repository DANTEFTPSITE and all worked fine without those
> messages..
>
> Ciao,
>  Angelo.
>
>
>
>> speculate that in this case the underlying cause is the same -- some
>> kind of (hopefully transient) network problem.  Obviously the TL code is
>> not changing from day to day (or indeed at any time since the release,
>> so far).
>>
>>      gnwiii> Running the same command a second time did not give any
>> error.
>>      gnwiii> tlmr skips the download of texlive.tlpdb.xz if the file is
>> very recent?
>>
>> Downloads are not skipped.  It looks to me like what happened, according
>> to the transcript provided, is that the fallback download with wget
>> succeeded.
>>
>> k
>>
>



--
Zdeněk Wagner
http://hroch486.icpf.cas.cz/wagner/
http://icebearsoft.euweb.cz