Strange error messages : SI buffer overflow, cache state reset

During restore I found following messages in the log:

->DEBUG: SendSharedInvalidMessage: SI buffer overflow
->DEBUG: ReceiveSharedInvalidMessages: cache state reset
(DEBUG: copy: line 4762, XLogWrite: new log file created - consider increasing WAL_FILES)
(DEBUG: recycled transaction log file 000000000000000D)
(DEBUG: recycled transaction log file 000000000000000E)
->DEBUG: ReceiveSharedInvalidMessages: cache state reset
->DEBUG: ReceiveSharedInvalidMessages: cache state reset
->DEBUG: ReceiveSharedInvalidMessages: cache state reset

Never saw them before. It would be of some help to have a table of
certain error messages. Couldn't find any. The database seems to be ok.

What is the SI-Buffer? My Test-box has got just 64MB,
database (dumped) 22MB, shared_buffers=default

regards

Johann Zuschlag
zuschlag@online.de