[mapguide-internals] MapGuide 2.2 beta crashes

[Gabriele Monfardini]

Hi Trevor,

thank you for the quick reply.

I've opened a ticket
http://trac.osgeo.org/mapguide/ticket/1469

with the demangled log

> Also, have you found any *easy* way to reproduce this?
The short answer is unfortunately no.
We have a repositories with a lot of folder and layers and maps.
We probably have a few problematic layers or missing ones, we're investigating.

The crashes are quite recurring (usually around 10/day but up to
40-50/day), but only a few of them leave some traces into the log.
I've reviewed Error log and Trace log to find out problematic calls,
but I've not found anything useful.

mapguide-apache error log is polluted by a lot of failed ACE_ASSERT
that make apache child abort with signal Aborted (6) or more rarely
Segmentation Fault (11)

ACE_ASSERT: file Configuration.cpp, line 1522 assertion failed for
'this->allocator_'.Aborting...
292 [Wed Oct 13 17:02:46 2010] [notice] child pid 27120 exit signal Aborted (6)

This two lines occurs hundreds of time a day and seems to not kill
mapguide nor mapguide-apache (but I'm not 100% sure)

We're using the OGR provider with gdal library compiled to support
PostgreSQL and multi thread.
No missing libraries nor symbols in gdal and FDO providers.

Number of crashes grows with concurrent load, at the point that we
need to carefully balance our clients to several mapguide servers.
The number of crashes appears also to grow with the use of features
that involve the use of the API in our PHP code, selecting, redlining
and so on.
Single features are tested in a separated test environment and they
work well. Not to say that testing server crashes very rarely even
under load.

I've carefully reviewed our scripts to catch all possible MgExceptions
and to do basic checks (layer exists before using it and so on) to
avoid making problematic calls to the server.
No single action seems to trigger the crash and we're not yet able to
reproduce reliably the problem.

Sometimes one single user is able to crash mapguide several times,
some others many customers doing about the same things are served
without problems and without crashes.

> There was a recent submission put into trunk to correct some Web Tier initialization behaviour.  We can try backporting it.
Regarding Web Tier initialization I have a question.

What exactly does the InitializeWebTier() call do?
All the PHP script appears to work also without. Is this mandatory?

In the following days we probably try the 2.2 RC1, hoping for better stability.

Regards,

Gabriele Monfardini