On Mon, 8 May 2017 12:48:29 -0600 Scott Marlowe <scott.marlowe@xxxxxxxxx> wrote: Hi Scott, Thank you for your input. > > The most likely cause of the difference would be that one server IS > honoring fsync requests from the db and the other one isn't. > > If you run pgbench on both (something simple like pgbench -c 1 -T 60, > aka one thread for 60 seconds) on a machine running on a 7200RPM hard > drive, you should get approximately 120 transactions per second Here are the results : #Kimsufi pgbench -c 1 -T 60 test starting vacuum...end. transaction type: TPC-B (sort of) scaling factor: 1 query mode: simple number of clients: 1 number of threads: 1 duration: 60 s number of transactions actually processed: 6618 latency average: 9.069 ms tps = 110.270771 (including connections establishing) tps = 110.283733 (excluding connections establishing) #Online starting vacuum...end. transaction type: TPC-B (sort of) scaling factor: 1 query mode: simple number of clients: 1 number of threads: 1 duration: 60 s number of transactions actually processed: 1150 latency average: 52.317 ms tps = 19.114403 (including connections establishing) tps = 19.115739 (excluding connections establishing) > > > -Why are regular queries much faster on this same server? > > That's a whole nother subject. Most likely the faster machine can fit > the whole db in memory, or has much faster memory, or the whole > dataset is cached etc etc. > The dataset is small (35 MB) and both servers have 4GB memory. It appears to be faster on the Online server. using 'dmidecode -t 17' : #Kimsufi Memory Device Array Handle: 0x0016 Error Information Handle: Not Provided Total Width: 64 bits Data Width: 64 bits Size: 2048 MB Form Factor: DIMM Set: None Locator: SO DIMM 0 Bank Locator: Channel A DIMM0 Type: DDR3 Type Detail: Synchronous Speed: 1066 MHz Manufacturer: 0x0000000000000000 Serial Number: 0x00000000 Asset Tag: Unknown Part Number: 0x000000000000000000000000000000000000 Rank: Unknown Configured Clock Speed: 1066 MHz [repeated for second locator] #Online Memory Device Array Handle: 0x0015 Error Information Handle: No Error Total Width: Unknown Data Width: Unknown Size: 4096 MB Form Factor: DIMM Set: None Locator: DIMM0 Bank Locator: BANK 0 Type: DDR3 Type Detail: Synchronous Unbuffered (Unregistered) Speed: 1600 MHz Manufacturer: <BAD INDEX> Serial Number: <BAD INDEX> Asset Tag: <BAD INDEX> Part Number: <BAD INDEX> Rank: 1 Configured Clock Speed: 1333 MHz Minimum voltage: Unknown Maximum voltage: Unknown Configured voltage: Unknown -- Bien à vous, Vincent Veyron https://libremen.com Logiciels de gestion, libres -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
