Thread: Information about XLogWrite

Hi,

Recently I got this error while the database was starting up. :

FATAL 2: XLogWrite: writerequest is past end of log

And the database did not startup, and finally I had to do a
pg_resetxlog. I tried going through the code which gave
this error but I was unable to comprehend much.

Could anyone tell me how exactly this error is caused. Also I would like
to know whether there is any detail
documentation about the WAL implemenation (also pg_resetxlog
implemenation) of postgres.

Thanks in advance.
Regards,
Aniket

Aniket Kulkarni <aniket_kulkarni@persistent.co.in> writes:
> Recently I got this error while the database was starting up. :
> FATAL 2: XLogWrite: writerequest is past end of log
> And the database did not startup, and finally I had to do a
> pg_resetxlog. I tried going through the code which gave
> this error but I was unable to comprehend much.

> Could anyone tell me how exactly this error is caused.

XLogWrite?  Not XLogFlush?  That'd be a new one on me.  Too bad you
flushed the broken xlog, I would have liked to look at it.

There is a known failure path (believed fixed in 7.2) whereby garbage
data in pg_log pages can lead to XLogFlush startup failures.
        regards, tom lane