Postgres SSL SYSCALL error: EOF detected with python and psycopg

I ran into this problem when running a slow query in a Droplet on a Digital Ocean instance. All other SQL would run fine and it worked on my laptop. After scaling up to a 1 GB RAM instance instead of 512 MB it works fine so it seems that this error could occur if the process is running out of memory.

The error: psycopg2.operationalerror: SSL SYSCALL error: EOF detected

The setup: Airflow + Redshift + psycopg2

When: Queries take a long time to execute (more than 300 seconds).

A socket timeout occurs in this instance. What solves this specific variant of the error is adding keepalive arguments to the connection string.

keepalive_kwargs = {    "keepalives": 1,    "keepalives_idle": 30,    "keepalives_interval": 5,    "keepalives_count": 5,}conection = psycopg2.connect(connection_string, **keepalive_kwargs)

Redshift requires a keepalives_idle of less than 300. A value of 30 worked for me, your mileage may vary. It is also possible that the keepalives_idle argument is the only one you need to set - but ensure keepalives is set to 1.

Link to docs on postgres keepalives.

Link to airflow doc advising on 300 timeout.

This issue occurred for me when I had some rogue queries running causing tables to be locked indefinitely. I was able to see the queries by running:

SELECT * from STV_RECENTS where status='Running' order by starttime desc;

then kill them with:

SELECT pg_terminate_backend(<pid>);