Re: [HACKERS] RelFileNode to Relation
On Sat, Oct 19, 2013 at 11:53 AM, Tom Lane wrote: > Soroosh Sardari writes: > > I need to get a Relation instance but I have only a RelFileNode! > > Why do you think you need to do that? Such a lookup is inherently the > wrong thing, because relations' relfilenode values are not fixed (unless > you have a lock on the relation, which presumably you don't). > > regards, tom lane > I know, it's against PG abstraction. In PG we don't need to know anything about relation in the smgr level. but in my project i want to encrypt all pages of a particular relation and decrypt it when those pages are fetching back to buffer. This behavior depends on some relation properties. So in smgropen I must get some knowledge about the relation and all of i have is RelFileNode. I can not see the pg_class for the relation oid, because smgropen may called before insertion in pg_class. Soroosh
Re: [HACKERS] RelFileNode to Relation
Soroosh Sardari writes: > I need to get a Relation instance but I have only a RelFileNode! Why do you think you need to do that? Such a lookup is inherently the wrong thing, because relations' relfilenode values are not fixed (unless you have a lock on the relation, which presumably you don't). regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
[HACKERS] RelFileNode to Relation
Hi I need to get a Relation instance but I have only a RelFileNode! I see the relcache.h, only the following function seems helpful extern Relation RelationIdGetRelation(Oid relationId); However, there is another problem, In the RelFileNode, only relNode exist and as comment said this is equivalent to pg_class.relfilenode and in some situation relation oid (pg_class.oid) and relation file node are not the same. So i cant use above function! Any idea? Regards, Soroosh Sardari Sharif University of Tech.
