Concurrent queries on client side

[Dimitar Misev]

.. seem to be shipped to the same rasserver. To reproduce you can use the attached code

cd applications/rasql
tar xzf test_concurrent_client.tar.gz
make query
./query

It sends the same query from two threads, and in the server log I see:

 [INFO] - 05/02/2016 12:57:36.241746: Request: 'select avg_cells(c) from test_rgb2 as c'...
 [INFO] - 05/02/2016 12:57:36.241782: Request: 'select avg_cells(c) from test_rgb2 as c'...
 [INFO] - 05/02/2016 12:57:36.241800: parsing...
 [INFO] - 05/02/2016 12:57:36.241813: parsing...
Error number: 300 Token: ( Line: 1 Column: 19
 [INFO] - 05/02/2016 12:57:36.241908: rasserver terminated.

[Alex Toader]

I do not think this is related to rasnet. It is related to raslib not being very thread safe.

[Dimitar Misev]

Patch is under review.

You can see the API changes in rasodmg that fixing this requires in this documentation patch​.

The issue in more detail: rasodmg is not thread-safe because it uses global r_Database and r_Transaction objects, which was further propagated in clientcomm. This patch removes the global objects; as a consequence, some rasodmg API change a bit with an additional parameter (the r_Transaction object, which in turn contains the r_Database object).

[Dimitar Misev]

Fixed finally, there are optional arguments in several places where the transaction object should be specified if thread-safety is needed. I will update the documentation as well to add notice about this.