[pgpool-general: 5775] deadlock messages after upgrade 3.2 -> 3.6.6

[Sebastian Benoit]

Hi,

i upgraded a pgpool installation from 3.2 to 3.6.6

After the upgrade i see these messages:

Oct 16 11:00:01 box1 pgpool[17817]: [67-1] 2017-10-16 11:00:01: pid 17817:
LOG:  pool_send_and_wait: Error or notice message from backend: : DB node
id: 0 backend pid: 24665 statement: "delete from gark.token where id=$1"
message: "deadlock detected"
Oct 16 11:00:01 box1 pgpool[17817]: [68-1] 2017-10-16 11:00:01: pid 17817:
LOG:  Execute: received deadlock error message from master node. query:
Oct 16 11:00:01 box1 pgpool[17817]: [69-1] 2017-10-16 11:00:01: pid 17817:
LOG:  pool_send_and_wait: Error or notice message from backend: : DB node
id: 1 backend pid: 5307 statement: "delete from gark.token where id=$1"
message: "invalid string in message"
Oct 16 11:00:01 box1 pgpool[21812]: [49-1] 2017-10-16 11:00:01: pid 21812:
LOG:  pool_send_and_wait: Error or notice message from backend: : DB node
id: 0 backend pid: 24996 statement: "delete from gark.token where id=$1"
message: "deadlock detected"
Oct 16 11:00:01 box1 pgpool[21812]: [50-1] 2017-10-16 11:00:01: pid 21812:
LOG:  Execute: received deadlock error message from master node. query:
Oct 16 11:00:01 box1 pgpool[21812]: [51-1] 2017-10-16 11:00:01: pid 21812:
LOG:  pool_send_and_wait: Error or notice message from backend: : DB node
id: 1 backend pid: 5804 statement: "delete from gark.token where id=$1"
message: "invalid string in message"

Now, before the upgrade i had these in my logs:

Oct  8 17:15:00 box1 pgpool[29658]: Parse: Unable to parse the query: "WITH
deleted AS (DELETE FROM gark.oauthaccesstoken WHERE expiration < NOW()
RETURNING *) SELECT count(*) FROM deleted" from client 192.168.4.10(45786)

(i'm not in charge of the application and was never able to get this fixed
there).

The old "Unable to parse the query" messages are gone now, instead i get the
above.

Do I have to worry about the "deadlock detected" message?

/Benno