RE: Fix of fake unlogged LSN initialization - Mailing list pgsql-hackers

From: Simon Riggs <simon@2ndquadrant.com>
>     From xlogdefs.h added by 9155580:
>     /*
>      * First LSN to use for "fake" LSNs.
>      *
>      * Values smaller than this can be used for special per-AM purposes.
>      */
>     #define FirstNormalUnloggedLSN  ((XLogRecPtr) 1000)

Yeah, I had seen it, but I didn't understand what kind of usage is assumed.


> I wonder why is that value 1000, rather than an aligned value or a whole WAL
> page?

I think that's because this fake LSN is not associated with the physical position of WAL records.


Regards
Takayuki Tsunakawa