PHP/Mapscript, apache2, mod_php - What is the status?

[Stephen Woodbridge]

Frank,

Thank you for your response. I kind of knew the answer, but I have had a 
few people ask me off list and thought it would be good to put a public 
face on this issue again.

I was not aware of the fact that OGR is thread unsafe at the moment, you 
might want to add a note to Sean's Thread Saftey page about this fact so 
others don't waste time because the stumble into it.

Best regards,
   -Steve W

Frank Warmerdam wrote:
> Stephen Woodbridge wrote:
> 
>> Benjamin,
>>
>> I never got any answer to this on list. It would be nice if there was 
>> a plan to  change the code to be more thread safe, but my guess is 
>> that will not happen without additional funding.
> 
> ...
>  > I think DM Solutions would have to address any
> 
>> issues specific to PHP/Mapscript.
> 
> 
> Steve,
> 
> I think you have a point that if thread safe mod_php use of mapserver
> is important to people, someone is going to have to put forward money or
> developer time to make it work smoothly.   I personally think it wouldn't
> be that hard to get it going modulo a few risky areas.  And the more
> mapserver users depending on thread safety, the move loving mapserver
> thread safety will get.
> 
> DM Solutions (or perhaps MapGears) would be a logical place to direct
> money to address this issue.
> 
> In the future, it is my hope that many organizations interested in 
> MapServer
> will become sponsors of OSGeo listing MapServer as the project they want
> to direct the majority of their support to.  How that money gets spent
> would (likely) be up to the MapServer PSC, but if the sponsors beat the
> drum about mod_php support, I'm sure some would go in that direction.
> 
> The other (in some ways preferrable) approach is for a decent developer
> with a long term interest in mod_php support to roll up their sleeves
> and work away at it.  I'm sure DM Solutions and the rest of us would be
> supportive and cooperative.
> 
>> Sean Gillies did a lot of work on thread safety (as did others) and 
>> wrote:
>>
>>   http://mapserver.gis.umn.edu/docs/faq/thread_safety
>>
>> This document also lays out what some of the major areas (Mapserver 
>> parser, PROJ, GDAL, DB Connection pooling) that could be improved to 
>> be more thread safe without putting coarse locks around those areas.
> 
> 
> Yes, this is a useful guideline.  Note that some areas (ie. GDAL) use
> a "big lock" and so could suffer congestion in heavy multi-threaded use,
> but should be pretty safe.  Others, like OGR don't have locking yet and
> are just very dangerous right now.  Like you, I also think there are
> some specific PHP related issues about which I have no clue.
> 
> Best regards,