On Fri, Feb 5, 2010 at 9:08 AM, Takahiro Itagaki
<itagaki.takah...@oss.ntt.co.jp> wrote:
>
> Fujii Masao <masao.fu...@gmail.com> wrote:
>
>> On Fri, Dec 5, 2008 at 11:41 PM, Randy Isbell <jisb...@cisco.com> wrote:
>> > An inconsistency exists between the segment name reported by
>> > pg_stop_backup() and the actual WAL file name.
>> >
>> > START WAL LOCATION: 10/FE1E2BAC (file 0000000200000010000000FE)
>> > STOP WAL LOCATION: 10/FF000000 (file 0000000200000010000000FF)
>
>> But it was rejected because its change might break the existing app.
>
> It might break existing applications if it returns "FE" instead of "FF",
> but never-used filename surprises users. (IMO, the existing apps probably
> crash if "FF" returned, i.e, 1/256 of the time.)
>
> Should it return the *next* reasonable log filename instead of "FF"?
> For example, 000000020000002000000000 for the above case.
Here is the patch that avoids a nonexistent file name, according to
Itagaki-san's suggestion. If we are crossing a logid boundary, the
next reasonable file name is used instead of a nonexistent one.
Regards,
--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
*** a/src/backend/access/transam/xlog.c
--- b/src/backend/access/transam/xlog.c
***************
*** 8057,8063 **** pg_stop_backup(PG_FUNCTION_ARGS)
*/
RequestXLogSwitch();
! XLByteToSeg(stoppoint, _logId, _logSeg);
XLogFileName(stopxlogfilename, ThisTimeLineID, _logId, _logSeg);
/* Use the log timezone here, not the session timezone */
--- 8057,8078 ----
*/
RequestXLogSwitch();
! if (stoppoint.xrecoff >= XLogSegSize)
! {
! XLogRecPtr recptr = stoppoint;
!
! /*
! * Since xlog segment file name is calculated by using XLByteToSeg,
! * it might indicate a nonexistent file (i.e., which ends in "FF")
! * when we are crossing a logid boundary. In this case, we use the
! * next reasonable file name instead of nonexistent one.
! */
! recptr.xlogid += 1;
! recptr.xrecoff = XLOG_BLCKSZ;
! XLByteToSeg(recptr, _logId, _logSeg);
! }
! else
! XLByteToSeg(stoppoint, _logId, _logSeg);
XLogFileName(stopxlogfilename, ThisTimeLineID, _logId, _logSeg);
/* Use the log timezone here, not the session timezone */
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
