I saw this just now:
TRAP: FailedAssertion("!(TransactionIdPrecedesOrEquals(safeXid,
snap->xmin))", File: "snapbuild.c", Line: 580)
while running 50 cascading instances on a single machine.
select version():
PostgreSQL 11devel_HEAD_20171219_2158_7d3583ad9ae5 on
x86_64-pc-linux-gnu, compiled by gcc (Debian 6.3.0-18) 6.3.0 20170516,
64-bit
I don't know if the admittedly somewhat crazy 50 instances make that
error acceptable/expected but I thought I'd report it anyway.
thanks,
Erik Rijkers