could not truncate directory "pg_subtrans": apparent wraparound

Hello,

today I saw the following message in the log file of a PostgreSQL 9.1.9 instance:

[2014-10-02 01:19:23.799 CEST : @ from ]LOG: konnte Verzeichnis »pg_subtrans« nicht leeren: anscheinender Überlauf

which apparently translates as

could not truncate directory "pg_subtrans": apparent wraparound

Googling this, the most reassuring link seems to be http://database-app.todaysummary.com/wap_q_database-application_16256, which says in several places that the message is harmless, but then goes on to talk about the pg_multixact subdirectory.

Is this message also harmless when it specifically mentions the pg_subtrans subdirectory? Or should I still be worried?

Some technical info:

PostgreSQL 9.1.9 on x86_64-unknown-linux-gnu, compiled by gcc (GCC) 4.4.7 20120313 (Red Hat 4.4.7-3), 64-bit

pg_control version number: 903
Catalog version number: 201105231
Database system identifier: 6034043295502253819
Database cluster state: in archive recovery
pg_control last modified: Do 02 Okt 2014 13:32:35 CEST
Latest checkpoint location: 14/F3044CD0
Prior checkpoint location: 14/F2A55618
Latest checkpoint's REDO location: 14/F2E31DE8
Latest checkpoint's TimeLineID: 1
Latest checkpoint's NextXID: 0/331367
Latest checkpoint's NextOID: 37926189
Latest checkpoint's NextMultiXactId: 1082
Latest checkpoint's NextMultiOffset: 2210
Latest checkpoint's oldestXID: 1795
Latest checkpoint's oldestXID's DB: 1
Latest checkpoint's oldestActiveXID: 331367
Time of latest checkpoint: Do 02 Okt 2014 13:20:01 CEST
Minimum recovery ending location: 14/F376B0C8
Backup start location: 0/0
Current wal_level setting: hot_standby
Current max_connections setting: 1000
Current max_prepared_xacts setting: 0
Current max_locks_per_xact setting: 64
Maximum data alignment: 8
Database block size: 8192
Blocks per segment of large relation: 131072
WAL block size: 8192
Bytes per WAL segment: 16777216
Maximum length of identifiers: 64
Maximum columns in an index: 32
Maximum size of a TOAST chunk: 1996
Date/time type storage: 64-bit integers
Float4 argument passing: by value
Float8 argument passing: by value

The pg_subtrans subdirectory holds a single file called 0005.

Best regards
Holger Friedrich