Re: CURRENT OF cursor without OIDs - Mailing list pgsql-hackers

From Mikheev, Vadim
Subject Re: CURRENT OF cursor without OIDs
Date
Msg-id 3705826352029646A3E91C53F7189E32016752@sectorbase2.sectorbase.com
Whole thread Raw
In response to CURRENT OF cursor without OIDs  (Ian Lance Taylor <ian@airs.com>)
List pgsql-hackers
> Oops I'm referring to client side cursors in our ODBC
> driver. We have no cross-transaction cursors yet though
> I'd like to see a backend cross-transaction cursor also.

Ops, sorry.
BTW, what are "visibility" rules for ODBC cross-tx cursor?
No Repeatable reads, no Serializability?
Do you hold some locks over table while cursor opened
(I noticed session locking in lmgr recently)?
Could ODBC cross-tx cursors be implemented using server
cross-tx cursors?

> > I think we'll be able to restore old tid along with other tuple
> > data from rollback segments, so I don't see any problem from
> > osmgr...
> 
> How do we detect the change of tuples from clients ?

What version of tuple client must see? New one?

> TIDs are invariant under osmgr. xmin is about to be
> unreliable for the purpose.

Seems I have to learn more about ODBC cross-tx cursors -:(
Anyway, *MSQL*, Oracle, Informix - all have osmgr. Do they
have cross-tx cursors in their ODBC drivers?

Vadim


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