Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> WALWriteLock contention is measurable on some workloads. In studying
> the problem briefly, a couple of questions emerged:
> 1. Doesn't it suck to rewrite an entire 8kB block every time, instead
> of only the new bytes (and maybe a few bytes following that to spoil
> any old data that might be there)?
It does, but it's not clear how to avoid torn-write conditions without
that.
> 2. I don't really understand why WALWriteLock is set up to prohibit
> two backends from flushing WAL at the same time. That seems
> unnecessary.
Hm, perhaps so.
regards, tom lane