Re: Reseting undo/redo logs

Edmon Begoli <ebegoli(at)gmail(dot)com> writes:
> One of the Greenplum segments went down and it cannot recover because
> "PANIC XX000 invalid redo/undo record in shutdown checkpoint
> (xlog.c:6576)"

> I am posting this question here because most casual users of
> Postgres/Greenplum are telling me that database is hosed, but I think
> that with pg_resetxlog and some
> (http://www.postgresql.org/docs/8.2/static/app-pgresetxlog.html) data
> loss I could at least "hack" database to come back up.

> What I am asking for help here is to help me calculate the reset
> values - where to find the most recent valid one and how to
> *specifically* calculate the reset ones.

pg_controldata should give you useful starting points. I don't think we
can offer any more help than what is on the pg_resetxlog reference page
as to what to do with them. (Though you might try reading the more
recent releases' versions of that page to see if anything's been
clarified.)

regards, tom lane