I started bisecting from e6df2e1 (stamp 9.4beta1, good) to 095d401 (bad). The problem revision appears to be 9402869:
commit 9402869 Author: Heikki Linnakangas <heikki.linnakan...@iki.fi> Date: Sat Jan 17 01:14:32 2015 +0200 Advance backend's advertised xmin more aggressively. which is somewhat logical given the crash location and symptoms. Bisection procedure used: For each step: ./configure --enable-debug --enable-cassert --prefix=/home/craig/pg/95 CFLAGS="-Og -ggdb -fno-omit-frame-pointer" && make clean install && make -C contrib/test_decoding/ clean install && rm -rf ~/tmp/slottest95 && PATH=$HOME/pg/95/bin:$PATH initdb -D ~/tmp/slottest95 && cp ~/tmp/{postgresql.conf,pg_hba.conf} ~/tmp/slottest95 && PATH=$HOME/pg/95/bin:$PATH PGPORT=5123 postgres -D ~/tmp/slottest95/ then manually: psql -p 5123 -c 'SELECT pg_create_logical_replication_slot('test', 'test_decoding');' PGPORT=5123 PATH=$HOME/pg/95/bin:$PATH pg_recvlogical -d postgres -S test --start -f - psql -p 5123 -c 'CREATE TABLE x AS SELECT xx FROM generate_series(1,10000) xx;' I have to go out now; I'll follow up further but wanted to update promptly.