> Ideally that path isn't taken very often. But I'm currently having a
> discussion off-list with a CMU student who seems to be seeing a case
> where it happens a lot. (She reports that both WALWriteLock and
> WALInsertLock are causes of a lot of process blockages, which seems to
> mean that a lot of the WAL I/O is being done with both held, which would
> have to mean that AdvanceXLInsertBuffer is doing the I/O.
> More when we figure out what's going on exactly...)
I would figure, that this is in a situation where a large transaction
fills one XLInsertBuffer, and a lot of WAL buffers are not yet written.
Andreas