[Qgis-psc] QGIS - SQL anywhere provider

[DeHaan, Dave]

Hi Martin,

Thank you for your email.  I have been tracking the QGIS development status and am aware of the need to patch the SQLA provider to accommodate multi-threaded rendering.  Beyond the necessary rendering fix, the SQLA provider also needs work to make it compatible with the DB Manager plugin.

Before committing resources to these maintenance tasks, I raised this issue a few weeks ago with the SAP project management team for SQLA and we are currently deliberating the future of the SQLA data provider.  The two options we are currently deciding between are:

1. Continue support for the SQLA provider.  In this case all required maintenance will be performed well before the 2.4 release.
    Or
2. Drop the SQLA provider in favour of accessing SQLA via the OGR provider.  The existing SQLA plugin (menu button and dialogue box for finding spatial tables) would be rewritten to instantiate an OGR provider rather than a SQLA provider.  We currently have an in-house OGR-SQLA driver and have tested the QGIS-OGR-SQLA combination; however, the OGR-SQLA  driver has not been released publicly and so would first need to be contributed to the OGR project before it can be picked up by QGIS.  

Due to the relatively high degree of flux in the QGIS data provider API compared to the more stable OGR driver API, at this point we are inclined to drop the QGIS-SQLA provider in favour of accessing SQLA via the QGIS-OGR provider.  This decision is pending internal approval of public release of an OGR-SQLA driver.

It is possible (perhaps likely) that all of the requirements of both our internal approval process and the OGR release cycle will not be accomplished prior to the QGIS 2.4 release.  In this case we would likely still drop the SQLA provider and rewrite the SQLA plugin to use the QGIS-OGR provider in the 2.4 release.  This would temporarily remove SQLA support from QGIS 2.4 as the shipped OGR provider would fail to initialize a SQLA driver, but advanced users would be able to recompile their own OGR library with SQLA driver support as soon as the SQLA driver is contributed to the OGR project.

I will keep the PSC and/or developer list posted as to our intentions for the SQLA provider once the decision is more firmly made.

Best regards,
Dave

--
David E. DeHaan
SAP SQL Anywhere Query Processing team
Dave.DeHaan at sap.com


-----Original Message-----
From: Martin Dobias [mailto:wonder.sk at gmail.com] 
Sent: Thursday, February 27, 2014 5:11 AM
To: ddehaan at sybase.com
Subject: QGIS - SQL anywhere provider

Hi Dave

I am not sure if you are still following QGIS development, but few
days ago the multi-threaded rendering has been merged to master branch
that will become 2.4 release. This change requires updates to the
vector data providers to support the new concept of feature sources -
without an update, the SQL anywhere provider is completely unusable.
Please provide a patch that would fix that - if not fixed in time for
2.4 release, we will have to remove the provider as unmaintained.

Regards
Martin