I found the cause of my issue.
In the source lib/srdb1/* some kind of pooling is used.
When kamailio needs a database connection, the cmp_db_id function checks
to see if there is already a database connection with the exact same
params (username, database, server etc..).
According to the PQ library every proces / thread should have it's own
database connection.
The db_postgres is setup to use asynchronous I/O with the PQ library.
So when two threads are using the same database connection it is
possible that,
the resultset from a query of thread A is returned to thread B.
The cmp_db_id function in lib/srdb1/db_id.c does _not_ check the PID.
I've created a small patch to fix the problems mentioned above.
The changes are made in lib/srdb1/* files
So if you apply them, it will be active for _every_ database module.
Maybe it's not needed for the mysql database,
but I *assume* it will not break when used on a mysql database. (not tested)
Maybe you will get a bit more database connections, but that depends on
which modules you're using.
What did I do:
* Added pid to the db_id struct.
* During initialization the pid is saved into the db_id struct.
* In cmp_db_id the pid is also checked when searching for a database
connection to be reused.
With kind Regards,
Robert Verspuy
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