Postgres SSL SYSCALL error: EOF detected with python and psycopg

Question

Using psycopg2 package with python 2.7 I keep getting the titled error: psycopg2.DatabaseError: SSL SYSCALL error: EOF detected

It only occurs when I add a WHERE column LIKE ''%X%'' clause to my pgrouting query. An example:

SELECT id1 as node, cost FROM PGR_Driving_Distance(
  'SELECT id, source, target, cost 
     FROM edge_table
     WHERE cost IS NOT NULL and column LIKE ''%x%'' ',
  1, 10, false, false)

Threads on the internet suggest it is an issue with SSL intuitively, but whenever I comment out the pattern matching side of things the query and connection to the database works fine.

This is on a local database running Xubuntu 13.10.

After further investigation: It looks like this may be cause by the pgrouting extension crashing the database because it is a bad query and their are not links which have this pattern.

Will post an answer soon ...

Answer 1

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.

Answer 2

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.

Answer 3

Very similar answer to what @FoxMulder900 did, except I could not get his first select to work. This works, though:

WITH long_running AS (
    SELECT pid, now() - pg_stat_activity.query_start AS duration, query, state
    FROM pg_stat_activity
    WHERE (now() - pg_stat_activity.query_start) > interval '1 minutes'
      and state = 'active'
)
SELECT * from long_running;

If you want to kill the processes from long_running just comment out the last line and insert SELECT pg_cancel_backend(long_running.pid) from long_running ;

Answer 4

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>);