On Thu, Jul 16, 2020 at 09:13:45PM +0530, Vishwa Kalyankar wrote: > I have two machines - one with 8GB RAM & 4core CPU and the other with 64GB > Ram & 24 core CPU. Both machines have the same DB (Postgres 12 + Postgis It looks like they're returning different number of rows, so definitely not the same DB. Also, they're performing about the same now... It looks like you didn't set shared_buffers, even for a machine with 64GB RAM. I think it's unusual to keep the default. On Thu, Jul 16, 2020 at 10:21:35PM +0530, Vishwa Kalyankar wrote: > Both the db's configurations are not same, I have tuned the db in both > machines according to https://pgtune.leopard.in.ua/#/ It looks like your low-end machine has no settings at all ? Did you forget to restart the server or use SET instead of ALTER SYSTEM SET ? > IPDS_KSEB=# set track_io_timing TO on; > IPDS_KSEB=# explain (analyze,buffers, settings) select * from kseb_geometry_trace_with_barrier_partition(5,'kottarakara_version',437,'htline',2); > > Function Scan on kseb_geometry_trace_with_barrier_partition > (cost=0.25..10.25 rows=1000 width=169) (actual time=24708.020..24708.048 rows=254 loops=1) > Buffers: shared hit=254235 read=1484 > I/O Timings: read=827.509 > Settings: effective_cache_size = '30GB', effective_io_concurrency = '2', max_parallel_workers = '24', max_parallel_workers_per_gather = '4', search_path = '"$user", public, topology', work_mem = '10MB' > Planning Time: 0.064 ms > Execution Time: 24772.587 ms > > Low End Machine > IPDS_KSEB=# explain (analyze,buffers, settings) select * from kseb_geometry_trace_with_barrier_partition(5,'kottarakara_version',437,'htline',2) ; > Function Scan on kseb_geometry_trace_with_barrier_partition (cost=0.25..10.25 rows=1000 width=169) (actual time=21870.311..21870.344 rows=389 loops=1) > Buffers: shared hit=774945 > Settings: search_path = '"$user", public, topology' > Planning Time: 0.089 ms > Execution Time: 21870.406 ms
