Jakub Ouhrabka <kuba(at)comgate(dot)cz> writes:
> Could it be that the failed connections were issued by autovacuum?
They clearly were: notice the reference to "Autovacuum context" in the
memory map. I think you are right to suspect that auto-analyze was
getting blown out by the wide bytea columns. Did you have any
expression indexes involving those columns?
regards, tom lane