9.1 doesn't start when died mid-backup

hi
got new 9.1, straight from git.
compiled, installed.
did initdb, and then set config values using this script:
perl -pi -e '
s/\A \s* (?: [#] \s* )? listen_addresses \s* = \s*.*/listen_addresses = \047*\047/x;
s/\A \s* (?: [#] \s* )? log_destination \s* = \s*.*/log_destination = \047stderr\047/x;
s/\A \s* (?: [#] \s* )? logging_collector \s* = \s*.*/logging_collector = on/x;
s/\A \s* (?: [#] \s* )? log_min_duration_statement \s* = \s*.*/log_min_duration_statement = 0/x;
s/\A \s* (?: [#] \s* )? log_line_prefix \s* = \s*.*/log_line_prefix = \047\%m \%u\(at)\%d \%p \%r \047/x;
s/\A \s* (?: [#] \s* )? log_temp_files \s* = \s*.*/log_temp_files = 0/x;
s/\A \s* (?: [#] \s* )? (log_checkpoints|log_connections|log_disconnections|log_lock_waits) \s* = \s*.*/$1 = on/x;
s/\A \s* (?: [#] \s* )? wal_level \s* = \s*.*/wal_level = hot_standby/x;
s/\A \s* (?: [#] \s* )? archive_mode \s* = \s*.*/archive_mode = on/x;
s/\A \s* (?: [#] \s* )? archive_command \s* = \s*.*/archive_command = \047\/bin\/true\047/x;
' data/postgresql.conf

afterwards I did start pg.

then, i connected with psql, and issued:
$ select pg_start_backup('xx');
pg_start_backup
-----------------
0/2000020
(1 row)

$ create database pgdba;
CREATE DATABASE

$ create user postgres with superuser;
CREATE ROLE

$ create user depesz with superuser;
CREATE ROLE

$ create database depesz with owner depesz;
CREATE DATABASE

Afterwards, I exited psql, and simulated power-failure, with:

=$ killall -9 postgres; killall -9 postmaster
postmaster: no process found

All pg processes were killed.

When I then tried to start Pg, I got:
=$ pg_ctl start
pg_ctl: another server might be running; trying to start server anyway
server starting

but it didn't start.

log looks like this:
=$ cat postgresql-2011-04-13_093859.log
2011-04-13 09:38:59.807 CEST @ 3446 LOG: database system was interrupted; last known up at 2011-04-13 09:38:43 CEST
2011-04-13 09:38:59.807 CEST @ 3446 LOG: database system was not properly shut down; automatic recovery in progress
2011-04-13 09:38:59.852 CEST @ 3446 LOG: redo starts at 0/2000020
2011-04-13 09:39:00.304 CEST @ 3446 LOG: record with zero length at 0/20018E8
2011-04-13 09:39:00.304 CEST @ 3446 LOG: redo done at 0/2001898
2011-04-13 09:39:00.304 CEST @ 3446 LOG: last completed transaction was at log time 2011-04-13 09:38:43.563356+02
2011-04-13 09:39:00.304 CEST @ 3446 FATAL: WAL ends before end of online backup
2011-04-13 09:39:00.304 CEST @ 3446 HINT: Online backup started with pg_start_backup() must be ended with pg_stop_backup(), and all WAL up to that point must be available at recovery.
2011-04-13 09:39:00.304 CEST @ 3444 LOG: startup process (PID 3446) exited with exit code 1
2011-04-13 09:39:00.304 CEST @ 3444 LOG: aborting startup due to startup process failure

interestingl7y backup_label got renamed to backup_label.old, and
contains:
START WAL LOCATION: 0/2000020 (file 000000010000000000000002)
CHECKPOINT LOCATION: 0/2000058
START TIME: 2011-04-13 09:38:19 CEST
LABEL: xx

Given the file was renamed, I retried:

=$ pg_ctl start
server starting

but again - it didn't work.

Log looks like this:

2011-04-13 09:44:06.844 CEST @ 3783 LOG: database system was interrupted while in recovery at 2011-04-13 09:38:59 CEST
2011-04-13 09:44:06.844 CEST @ 3783 HINT: This probably means that some data is corrupted and you will have to use the last backup for recovery.
2011-04-13 09:44:06.845 CEST @ 3783 LOG: database system was not properly shut down; automatic recovery in progress
2011-04-13 09:44:06.877 CEST @ 3783 LOG: redo starts at 0/2000020
2011-04-13 09:44:07.316 CEST @ 3783 LOG: record with zero length at 0/20018E8
2011-04-13 09:44:07.316 CEST @ 3783 LOG: redo done at 0/2001898
2011-04-13 09:44:07.316 CEST @ 3783 LOG: last completed transaction was at log time 2011-04-13 09:38:43.563356+02
2011-04-13 09:44:07.316 CEST @ 3783 FATAL: WAL ends before end of online backup
2011-04-13 09:44:07.316 CEST @ 3783 HINT: Online backup started with pg_start_backup() must be ended with pg_stop_backup(), and all WAL up to that point must be available at recovery.
2011-04-13 09:44:07.316 CEST @ 3776 LOG: startup process (PID 3783) exited with exit code 1
2011-04-13 09:44:07.316 CEST @ 3776 LOG: aborting startup due to startup process failure

So, it looks to me that by killing postgres mid-backup I made it end up in some state that doesn't let it start again.

I *think* it might be related to this:
http://archives.postgresql.org/pgsql-hackers/2011-03/msg01490.php and more
specifically, with this:
http://archives.postgresql.org/pgsql-hackers/2011-03/msg01627.php

Best regards,

depesz

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