On Wednesday, January 21, 2015, Amit Kapila <amit.kapil...@gmail.com> wrote:
> On Wed, Jan 21, 2015 at 12:47 PM, Amit Langote < > langote_amit...@lab.ntt.co.jp > <javascript:_e(%7B%7D,'cvml','langote_amit...@lab.ntt.co.jp');>> wrote: > > > > On 20-01-2015 PM 11:29, Amit Kapila wrote: > > > Note - I have yet to handle the new node types introduced at some > > > of the places and need to verify prepared queries and some other > > > things, however I think it will be good if I can get some feedback > > > at current stage. > > > > > > > I got an assertion failure: > > > > In src/backend/executor/execTuples.c: ExecStoreTuple() > > > > /* passing shouldFree=true for a tuple on a disk page is not sane */ > > Assert(BufferIsValid(buffer) ? (!shouldFree) : true); > > > > Good Catch! > The reason is that while master backend is scanning from a heap > page, if it finds another tuple/tuples's from shared memory message > queue it will process those tuples first and in such a scenario, the scan > descriptor will still have reference to buffer which it is using from > scanning > from heap. Your proposed fix will work. > > > After fixing this, the assertion failure seems to be gone though I > > observed the blocked (CPU maxed out) state as reported elsewhere by Thom > > Brown. > > > > Does it happen only when parallel_seqscan_degree > max_worker_processes? > I have max_worker_processes set to the default of 8 while parallel_seqscan_degree is 4. So, this may be a case different from Thom's. Thanks, Amit
