Re: FDW for PostgreSQL

Shigeru Hanada wrote:
> Tom Lane wrote:
>>             It ought to be pulling the rows back a few at a time, and
>> that's not going to work well if multiple scans are sharing the same
>> connection.  (We might be able to dodge that by declaring a cursor
>> for each scan, but I'm not convinced that such a solution will scale up
>> to writable foreign tables, nested queries, subtransactions, etc.)
> 
> Indeed the FDW used CURSOR in older versions.  Sorry for that I have
> not looked writable foreign table patch closely yet, but it would
> require (may be multiple) remote update query executions during
> scanning?

It would for example call ExecForeignUpdate after each call to
IterateForeignScan that produces a row that meets the UPDATE
condition.

Yours,
Laurenz Albe