On Mon, 8 May 2017 12:48:29 -0600
Scott Marlowe <[email protected]> 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
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