BUG #15447: Dramatic slowdown in psqlODBC when a debugger is attached to the process

The following bug has been logged on the website:

Bug reference: 15447
Logged by: Pierre le Riche
Email address: postgresql(at)pleasedontspam(dot)me
PostgreSQL version: 10.5
Operating system: Windows 10 X64 1803
Description:

I've been comparing the performance of various database back-ends and ODBC
drivers and I've noticed that the psqlODBC driver slows down dramatically
when a debugger is attached to the application process - up to an order of
magnitude or more. In particular the SQLExecDirect, SQLFetch and
SQLMoreResults calls are severely affected. In my case I am using the
Embarcadero Delphi IDE for my application development and when I run the
application without debugging the performance is comparable to other
drivers, but when I run the application with the debugger attached opening
an SQL query becomes really slow. I have also tested the Devart ODBC driver
for PostgreSQL and it doesn't exhibit this problem. The MySQL and MSSQL ODBC
drivers also do not show any noticeable slowdown when the application is run
with the Delphi debugger attached. I have tested with both 32-bit and 64-bit
applications and psqlODBC drivers and the results are the same. I have
tested with both the latest psqlODBC driver as well as an older one (v8),
also with the same result. I have scanned through the latest psqlODBC
source, but nothing jumps out at me so I am at a bit of a loss as to what
can be causing this.

Thanks!