On Thu, Mar 12, 2015 at 4:22 PM, Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: > > On 10-03-2015 PM 01:09, Amit Kapila wrote: > > On Tue, Mar 10, 2015 at 6:50 AM, Haribabu Kommi < kommi.harib...@gmail.com> > >> Is this patch handles the cases where the re-scan starts without > >> finishing the earlier scan? > >> > > > > Do you mean to say cases like ANTI, SEMI Join (in nodeNestLoop.c) > > where we scan the next outer tuple and rescan inner table without > > completing the previous scan of inner table? > > > > I have currently modelled it based on existing rescan for seqscan > > (ExecReScanSeqScan()) which means it will begin the scan again. > > Basically if the workers are already started/initialized by previous > > scan, then re-initialize them (refer function ExecReScanFunnel() in > > patch). > > > > From Robert's description[1], it looked like the NestLoop with Funnel would > have Funnel as either outer plan or topmost plan node or NOT a parameterised > plan. In that case, would this case arise or am I missing something? >
Probably not if the costing is right and user doesn't manually disable plans (like by set enable_* = off). However we should have rescan code incase it chooses the plan such that Funnel is inner node and I think apart from that also in few cases Rescan is required. With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
