Re: EvalPlanQual behaves oddly for FDW queries involving system columns

On 2015/03/13 11:46, Etsuro Fujita wrote:
> BTW, what do you think about opening/locking foreign tables selected for
> update at InitPlan, which the original patch does?  As I mentioned in
> [1], ISTM that ExecOpenScanRelation called from ExecInitForeignScan is
> assuming that.

> [1] http://www.postgresql.org/message-id/54BCBBF8.3020103@lab.ntt.co.jp

Let me explain further.  Here is the comment in ExecOpenScanRelation:
     * Determine the lock type we need.  First, scan to see if target 
relation     * is a result relation.  If not, check if it's a FOR UPDATE/FOR SHARE     * relation.  In either of those
cases,we got the lock already.
 

I think this is not true for foreign tables selected FOR UPDATE/SHARE, 
which have markType = ROW_MARK_COPY, because such foreign tables don't 
get opened/locked by InitPlan.  Then such foreign tables don't get 
locked by neither of InitPlan nor ExecOpenScanRelation.  I think this is 
a bug.  To fix it, I think we should open/lock such foreign tables at 
InitPlan as the original patch does.

Best regards,
Etsuro Fujita