Re: How to reset WAL enveironment

"Mikheev, Vadim" wrote:
> 
> > > > Probably this is caused by my trial (local) change
> > > > and generated an illegal log output.
> > > > However it seems to mean that WAL isn't always
> > > > redo-able.
> > >
> > > Illegal log output is like disk crash - only BAR can help.
> >
> > But redo-recovery after restore would also fail.
> > The operation which corresponds to the illegal
> > log output aborted at the execution time and
> > rolling back by redo also failed. It seems
> > preferable to me that the transaction is rolled
> > back by undo.
> 
> What exactly did you change in code?

I'm changing REINDEX under postmaster to be safe under WAL.
(When I met Tatsuo last week he asked me if REINDEX under
postmaster is possible and I replied yes. However I'm
not sure REINDEX under postmaster is sufficiently safe
especially under WAL and I started to change REINDEX to
be rollbackable using relfilenode.)

> What kind of illegal log output?

Probably a new block was about to be inserted into new
relfilenode suddenly. 
I've been anxious about rolling back by redo.
There's no guarantee that retrying redo-log would never
fail.

I see a vacuum failure now.
I probably fixed a bug(see pgsql-committers) but
there seems to remain other bugs.

Regards.

Hirohi Inoue