Information about XLogWrite

Started by Aniket Kulkarniabout 24 years ago2 messageshackers
Jump to latest
#1Aniket Kulkarni
aniket_kulkarni@persistent.co.in

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

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Aniket Kulkarni (#1)
Re: Information about XLogWrite

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