[cx-oracle-users] Safely replacing a SessionPool after database restart?

[Forest W. [sf] <mo...@ti...>]

I'm trying to get my code to handle a database restart automatically, 
which turns out to be tricky when using a SessionPool.

My first approach was to use SessionPool.drop() instead of release() when 
a dead connection was detected, but it turns out that drop() fails after a 
database restart.

My second approach was to replace the SessionPool entirely when a dead 
connection was detected.  In order to keep any remaining old connections 
from being released to the new pool, I tried waiting for SessionPool.busy 
to reach 0 before doing the replacement.  Unfortunately, in practice, it 
never reached 0.  This was probably because release() fails with my dead 
connection, so it can never be returned to the pool.  In other words, a 
kind of deadlock.

Out of curiosity, I tried deliberately releasing a connection to a 
SessionPool it didn't come from, to see how cx_Oracle would respond.  It 
raised a cx.ProgrammingError.  Is this safeguard guaranteed to work?  If 
so, I suppose I can replace my SessionPool as soon as a dead connection is 
found, and rely on this safeguard to keep anything bad from happening when 
remaining old connections get returned to the new pool.

Is there a better approach?