On Sat, Oct 6, 2012 at 4:05 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Atri Sharma <atri.j...@gmail.com> writes: >> On Sat, Oct 6, 2012 at 3:45 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> Atri Sharma <atri.j...@gmail.com> writes: >>>> I am trying to identify foreign scans uniquely. > >>> What do you mean by "identify"? What are you trying to accomplish, >>> and in what context? > >> I am trying to identify the situation where a query has multiple >> foreign scans.In that case,I need to check whether the current scan is >> the same as a previous scan or not.If not,then I think it means that >> multiple scans are in progress on the same backend. > > Well, if you search the plan tree and find more than one ForeignScan > node, it means there's more than one foreign scan. It doesn't seem to > me to be very complicated. Now, if you're wondering whether they > reference the same server or not, that's a bit harder. I guess you > could look at the RTEs, fetch the foreign-table data for each FT > relation OID, and see if the same server is referenced. > > regards, tom lane
Hi Tom, Thanks for the extensive reply. The issue I am trying to resolve is that if two scans are taking place on the same backend(due to the same query),then,the server is crashing. e.g. foreign_table is a foreign table SELECT * FROM foreign_table UNION SELECT * FROM foreign_table; results in a crash of the server. I think it is because I am not saving the state of the scan,so,if multiple scans a re running on the same backend,then,it is causing the crash. Any hints on how I can detect this condition please? Atri -- Regards, Atri l'apprenant -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
