Re: [HACKERS] postgres_fdw cost estimation defaults and documentation

2017-06-07 Thread Robert Haas
On Tue, Jun 6, 2017 at 9:24 PM, Jim Finnerty wrote: > In some MPP systems, networking costs are modeled separately from I/O costs, > processor costs, or memory access costs. I think this is what Ashutosh may > have been getting at with /per-packet/ costs: in a more

Re: [HACKERS] postgres_fdw cost estimation defaults and documentation

2017-06-06 Thread Robert Haas
On Mon, Jun 5, 2017 at 2:37 PM, Jeff Janes wrote: > In the documentation for fdw_startup_cost, it says "This represents the > additional overhead of establishing a connection, parsing and planning the > query on the remote side, etc.". I think that "establishing a

Re: [HACKERS] postgres_fdw cost estimation defaults and documentation

2017-06-05 Thread Ashutosh Bapat
On Tue, Jun 6, 2017 at 12:07 AM, Jeff Janes wrote: > > The default value for fdw_tuple_cost is 0.01, which seems way too low. If I > set up a loop-back foreign server with a large fetch_size, then tests like: > > select * from pgbench_accounts except select * from >

[HACKERS] postgres_fdw cost estimation defaults and documentation

2017-06-05 Thread Jeff Janes
The default value for fdw_tuple_cost is 0.01, which seems way too low. If I set up a loop-back foreign server with a large fetch_size, then tests like: select * from pgbench_accounts except select * from loopback.pgbench_accounts vs select * from pgbench_accounts except select * from