On 2020-Aug-03, Alvaro Herrera wrote:
> > lsn | checksum | flags | lower | upper | special | pagesize |
> > version | prune_xid
> > --------------+----------+-------+-------+-------+---------+----------+---------+-----------
> > A0A/99BA11F8 | -215 | 0 | 180 | 7240 | 8176 | 8192
> > | 4 | 0
> >
> > As I understand what we're looking at, this means the WAL stream was
> > assuming this page was last touched by A0A/AB2C43D0, but the page itself
> > thinks it was last touched by A0A/99BA11F8, which means at least one write
> > to the page is missing?
>
> Yeah, that's exactly what we're seeing. Somehow an older page version
> was resurrected. Of course, this should never happen.
... although, the block should have been in shared buffers, and it is
there that the previous WAL record would have updated -- not necessarily
flushed to disk.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
