Heikki Linnakangas wrote:
> In utils/adt/tid.c, there's two mysterious functions with no comments,
> and no-one calling them inside backend code AFAICT: currtid_byreloid
> and currtid_byrelname. What do they do/did?
>
If you have a look at the CVS annotations (
http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/tid.c?annotate=1.57
) you can see that they were introduced at version 1.12 (
http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/adt/tid.c.diff?r1=1.11;r2=1.12;f=h
)
which has the comment:
The 1st step to implement new type of scan,TidScan.
Now WHERE restriction on ctid is allowed though it is
sequentially scanned.
I often find I have to do this sort of digging to understand what's going on (or find a guilty party :-) ).
cheers
andrew