[mapserver-dev] Mapserver thread safety

[thomas bonfort]

Nice catch!
Returning a reference to epsgCode in that function is, to my
knowledge, to the best undefined behavior, clearly not thread safe,
and should be fixed.

--
thomas

On 13 August 2013 16:31,  <Michel.Dastous at bentley.com> wrote:
> About WFS/WMS thread safety, looking at mapows.c I found a single static
> variable (epsgCode) used in msOWSGetEPSGProj().
>
>
>
> Instead of returning a static pointer, the method could easily take a buffer
> + buffer size as parameters… Not a big deal except that 62 calls to that
> function will have to be modified.
>
>
>
> Is this the only thing that make WFS/WFS server non thread safe?
>
>
>
> Thanks !
>
>
>
>
>
> From: Michel Dastous
> Sent: Tuesday, August 13, 2013 9:45 AM
> To: 'Umberto Nicoletti'
>
>
> Cc: MapServer Dev Mailing List
> Subject: RE: [mapserver-dev] Mapserver thread safety
>
>
>
> Thank you very much! I will test it as soon as possible.
>
>
>
> From the page you sent me I realized that WMS/WFS server is not thread safe
> (“WMS/WFS server: static data used for state of dispatcher”).   Is there any
> plan to fix this ? I could not find any ticket about this
>
>
>
> Thanks.
>
>
>
> From: Umberto Nicoletti [mailto:umberto.nicoletti at gmail.com]
> Sent: Tuesday, August 13, 2013 8:49 AM
> To: Michel Dastous
> Cc: MapServer Dev Mailing List
> Subject: Re: [mapserver-dev] Mapserver thread safety
>
>
>
> FYI, I've opened this pull request which should fix the Oracle spatial issue
> you are seeing:
>
> https://github.com/mapserver/mapserver/pull/4729
>
> Let me know if it works for you.
>
>
>
> BR,
>
> Umberto
>
> On Tue, Aug 13, 2013 at 8:23 AM, Umberto Nicoletti
> <umberto.nicoletti at gmail.com> wrote:
>
> Michel,
>
> this page attempts to keep track of which Mapserver components are thread
> safe:
>
>
>
> http://mapserver.org/faq.html#is-mapserver-thread-safe
>
>
>
> it must not be completely up to date as, as you found out, Oracle is listed
> as safe, while it's not.
>
> As for fixing it, it should be relatively easy as those two variables can be
> made local to the functions using them.
>
>
>
> Please open an issue and I will look into it asap.
>
>
>
> Umberto
>
>
>
>
>
> On Mon, Aug 12, 2013 at 9:44 PM, <Michel.Dastous at bentley.com> wrote:
>
> Hi all,
>
>
>
> I’ve been testing mapserver and its c# mapscript API for a while now, and I
> have noticed that making simultaneous Draw request on multiple maps
> containing Oracle layer will end up in memory corruption.  No surprise here
> since maporaclespatial.c uses static variables (ordinates_tdo and
> ordinates).
>
>
>
> My question is: Does anyone have already evaluated how much work it would
> require to make it thread safe (i.e remove those static variables from the
> code) ?
>
>
>
> Furthermore, I have also tested the MSSQL plugin which is stable under same
> conditions, unfortunately it doesn’t seem to scale very well my 4 core
> machines with maximum CPU usage of 15%.
>
>
>
> I don’t think the problem come from mapserver’ s rendering engine… when
> drawing a map with inlined data, I could easily reach a 90% usage.
>
>
>
> So any suggestions/information would be welcome.
>
>
>
> Thanks.
>
>
>
>
>
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