[mapguide-internals] Release of MGOS 1.2.0

[Frank Warmerdam]

Jason Birch wrote:
> Sort of.
> 
> Haris has done some initial investigation, and I've tested the binary,
> but he had to leave before discussing implications with Frank.  Also, I
> think that we may need to look at GDAL version.  The 3.2.2 GDAL Provider
> is still on GDAL 1.3, while MapGuide is running 1.4.0.  Frank commented
> that running these two versions concurrently under Linux could cause
> some severe issues.  Also, the remaining stability issues that I'm
> seeing appear -- to my non-developer eyes -- to be related to memory
> issues in GDAL, and there's no way we're going to be able to convince
> Frank to look at GDAL 1.3 if my guess about the source is correct.

Folks,

In discussions with Haris, it has become clear to me that the stability
problems relate to using fdogdal in multithreaded fashion with no
internal serialization.

The underlying GDAL library is "fairly" threadsafe as long as only
one thread at a time is accessing a given dataset.  But even that is
not at all assured under the current use pattern.

I think we need to put a BigLock (tm) around GDAL in fdogdal 3.2.2
and a finer grained locking system in fdogdal 3.3 (trunk).

We could use Haris' patch though from a quick description it does
not sound to me like it is comprehensive.  I'm also willing to prepare
a fix for this if someone can test it heavily.

I'd add that there is no (apparent) way of testing multithreaded
access in the current regression tests for FDO which is a bit
unfortunate.

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org