Oracle Managed Data Access The underlying provider failed on Open

Question

In my C# console app using .Net 4.6.1 and Oracle.ManagedDataAccess and Oracle.ManagedDataAccess.EntityFramework i get an error in the following code. The code works the first 74 times, then fails with the error:

The underlying provider failed on Open

THING tempThing = thingEntity.THINGS
    .AsNoTracking()
    .Where(d => d.THING_ID == thi)
    .SingleOrDefault();

Answer 1

This issue occurred when switching from the Oracle.DataAccess driver to the managed driver.

As a Q&D fix, I found that I can increase the Max Pool Size in the connection string. This worked for now, but the real answer is to handle disposing of the connections better.

Max Pool Size=200;