Hi Thomas, I was testing this feature with v20 patch, and I got a crash while doing large joins with small work_mem, and lots of workers as below.
-- Machine Configuration: (d1.xlarge) CUPs : 8 , RAM : 16GB , SIze : 640GB -- postgres.conf setting as below: work_mem = *64kB* max_parallel_workers_per_gather = *128* max_parallel_workers = *64* enable_mergejoin = off enable_nestloop = off enable_hashjoin = on force_parallel_mode = on seq_page_cost = 0.1 random_page_cost = 0.1 effective_cache_size = 128MB parallel_tuple_cost = 0 parallel_setup_cost = 0 parallel_synchronization_cost = 0 -- created only one table "lineitem" of size 93GB. postgres=# select pg_size_pretty(pg_total_relation_size('lineitem')); pg_size_pretty ---------------- 93 GB (1 row) [centos@centos-prabhat bin]$ vi test10.sql explain (analyze, costs off) select count(*) from lineitem t1 join lineitem t2 using(l_suppkey) join lineitem t3 using(l_suppkey); select count(*) from lineitem t1 join lineitem t2 using(l_suppkey) join lineitem t3 using(l_suppkey); [centos@centos-prabhat bin]$ ./psql postgres -a -f test10.sql > test10.out [centos@centos-prabhat bin]$ vi test10.out explain (analyze, costs off) select count(*) from lineitem t1 join lineitem t2 using(l_suppkey) join lineitem t3 using(l_suppkey); psql:test10.sql:2: WARNING: terminating connection because of crash of another server process DETAIL: The postmaster has commanded this server process to roll back the current transaction and exit, because another server process exited abnormally and possibly corrupted shared memory. HINT: In a moment you should be able to reconnect to the database and repeat your command. psql:test10.sql:2: server closed the connection unexpectedly This probably means the server terminated abnormally before or while processing the request. psql:test10.sql:2: connection to server was lost Kindly check, if you can reproduce the same at your end. *Thanks & Regards,* *Prabhat Kumar Sahu* Mob: 7758988455 Skype ID: prabhat.sahu1984 www.enterprisedb.co <http://www.enterprisedb.com/>m <http://www.enterprisedb.com/> On Thu, Oct 5, 2017 at 1:15 PM, Thomas Munro <thomas.mu...@enterprisedb.com> wrote: > On Thu, Oct 5, 2017 at 7:07 PM, Rushabh Lathia <rushabh.lat...@gmail.com> > wrote: > > v20 patch set (I was trying 0008, 0009 patch) not getting cleanly apply > on > > latest commit also getting compilation error due to refactor in below > > commit. > > > > commit 0c5803b450e0cc29b3527df3f352e6f18a038cc6 > > Hi Rushabh > > I am about to post a new patch set that fixes the deadlock problem, > but in the meantime here is a rebase of those two patches (numbers > changed to 0006 + 0007). In the next version I think I should > probably remove that 'stripe' concept. The idea was to spread > temporary files over the available temporary tablespaces, but it's a > terrible API, since you have to promise to use the same stripe number > when opening the same name later... Maybe I should use a hash of the > name for that instead. Thoughts? > > -- > Thomas Munro > http://www.enterprisedb.com >