[mapguide-internals] RE: PATCH: Raster stability fixes, ticket #462

[Jason Birch]

I think that this patch should be implemented for two reasons.

First, I believe that this is no more of a sledgehammer approach than the existing guard.

Second, getting coordination between a skilled MapGuide developers that can work though the threading issues and the GDAL Provider developer has been attempted in the past and failed because nobody stepped up to the plate from the MapGuide community.

Checking this in as a temporary stability measure allows us to have a reasonable (if slow) raster story for the 2.1 release.

Of course, if there are developers from both the FDO and MapGuide communities that are able to work together to properly resolve this issue before the FDO 3.4 release (it's at RC3) and the MapGuide 2.1 release, then that would be ideal.

Jason

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Bruce Dechant
Sent: March-27-09 8:55 AM
To: MapGuide Internals Mail List
Subject: [mapguide-internals] RE: PATCH: Raster stability fixes, ticket #462

I totally agree - the locking needs to be in the provider.

Thanks,
Bruce


-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Traian Stanev
Sent: Friday, March 27, 2009 9:40 AM
To: MapGuide Internals Mail List
Subject: [mapguide-internals] RE: PATCH: Raster stability fixes, ticket #462


It does look like a sledgehammer approach -- what if some day there is a raster provider that works ok and doesn't need the locks? If anything, the lock should be in the FDO provider.

Traian


-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Walt Welton-Lair
Sent: Friday, March 27, 2009 11:11 AM
To: MapGuide Internals Mail List
Subject: [mapguide-internals] RE: PATCH: Raster stability fixes, ticket #462

The memory patch (mapguide_raster_unalloc.5.patch) looks good, and I'll submit that.

The stability patch (mapguide_raster_stability.patch) looks reasonable, but I'd like another 1 or 2 people to also look at it.  It's significant since it limits MapGuide to processing one raster stylization request at a time, but I guess that's better than having a dead lock.  Anyone know where the thread-unsafe code actually is?  Is it in the provider itself?  Can the mutex be moved closer to the actual thread-unsafe code?

Walt

-----Original Message-----
From: mapguide-internals-bounces at lists.osgeo.org [mailto:mapguide-internals-bounces at lists.osgeo.org] On Behalf Of Jason Birch
Sent: Friday, March 27, 2009 3:10 AM
To: mapguide-internals at lists.osgeo.org
Subject: [mapguide-internals] PATCH: Raster stability fixes, ticket #462

Hi,

Haris has been working on the raster stability problem against MapGuide 2.0.2.  I was having the same problems, and was able to duplicate on 2.1.  I have worked with Haris to create patches against trunk that address a couple of the problems and increase stability immensely.

Could someone please review the patches attached to:

http://trac.osgeo.org/mapguide/ticket/462

and commit them to trunk if appropriate?

My feeling is that the connection management stuff may need some additional work, since limiting the connection pool to 1 for single-threaded providers doesn't appear to have the desired effect.  However, getting both of these patches into 2.1 would at least improve stability for Raster users.

Jason_______________________________________________
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