Comment 2 for bug 733115

Further analysis shows that the underlying problem is that pping interprets a database error as a lost database connection (!). Each time this happens, it creates a new connection. The old one is discarded, but not closed.

In your case, you likely had hundreds of RRD filed created that were already registered in your migrated database, which caused pping to quickly fill up the amount of available non-superuser connections to PostgreSQL. When it could no longer open a new connection, the daemon crashed. This was confirmed on my dev server.

This latter bug should probably be filed separately...