ERROR log entry in order book stream during shutdown

[bartekn]

What version are you using?

Horizon 1.8.0 RC

What did you do?

Shutdown Horizon.

What did you expect to see?

No level="error" log entries emitted by cancelled contexts during shutdown.

What did you see instead?

ERRO[2020-08-27T19:27:13.113+02:00] could not apply updates from order book stream  error="Error updating: Error from GetAllOffers: canceling statement due to user request" pid=29939 service=expingest
ERRO[2020-08-27T19:27:13.113+02:00] could not apply updates from order book stream  error="Error starting repeatable read transaction: beginTx failed: context canceled" pid=29939 service=expingest

[bartekn]

@tamirms can you take a look? If it's too complicated to fix before tomorrow please move it to 1.9.0 milestone.