Alban Hertroys <alban@magproductions.nl> writes:
> Is it possible that there is some limitation to the number of statements
> in a single transaction?
2^32, and if you'd exceeded it, you'd get a very specific error message
saying so.
> As they're inserts, and therefore not even touching the same data, I'm
> quite certain it's not some kind of row locking issue (does that even
> happen at all with MVCC?).
I'm not. In particular this could be a foreign key locking issue ---
does the target table have foreign keys, and if so could inserts from
different transactions be referencing the same master row?
regards, tom lane