Re: PANIC caused by open_sync on Linux

Greg Smith <gsmith@gregsmith.com> wrote:

> There's a couple of potential to-do list ideas that build on the changes 
> in this area in 8.3:
> 
> -Aggressively pre-allocate WAL segments 
> -Space out checkpoint fsync requests in addition to disk writes
> -Consider re-inserting a smarter bgwriter all-scan that writes sorted by 
> usage count during idle periods

I'd like to add:
- Remove "filling with zero" before we recycle WAL segments.

If it is not needed, we can avoid buffered i/o on open_sync except
first allocation of segments. I think we can do it if we have more
robust WAL records that can ignore garbage data written before.

Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center