Re: HDD vs SSD without explanation

2018-07-17 Thread Neto pr
Thanks all, but I still have not figured it out. This is really strange because the tests were done on the same machine (I use HP ML110 Proliant 8gb RAM - Xeon 2.8 ghz processor (4 cores), and POSTGRESQL 10.1. - Only the mentioned query running at the time of the test. - I repeated the query 7 tim

Re: HDD vs SSD without explanation

2018-01-16 Thread Mark Kirkwood
On 16/01/18 23:14, Neto pr wrote: 2018-01-15 20:04 GMT-08:00 Mark Kirkwood : On 16/01/18 13:18, Fernando Hevia wrote: The 6 Gb/s interface is capable of a maximum throughput of around 600 Mb/s. None of your drives can achieve that so I don't think you are limited to the interface speed. Th

Re: HDD vs SSD without explanation

2018-01-16 Thread Nicolas Charles
Le 16/01/2018 à 11:14, Neto pr a écrit : 2018-01-15 20:04 GMT-08:00 Mark Kirkwood : On 16/01/18 13:18, Fernando Hevia wrote: The 6 Gb/s interface is capable of a maximum throughput of around 600 Mb/s. None of your drives can achieve that so I don't think you are limited to the interface spee

Re: HDD vs SSD without explanation

2018-01-16 Thread Neto pr
2018-01-15 20:04 GMT-08:00 Mark Kirkwood : > On 16/01/18 13:18, Fernando Hevia wrote: > >> >> >> >> The 6 Gb/s interface is capable of a maximum throughput of around 600 >> Mb/s. None of your drives can achieve that so I don't think you are limited >> to the interface speed. The 12 Gb/s interface s

Re: HDD vs SSD without explanation

2018-01-15 Thread Mark Kirkwood
On 16/01/18 13:18, Fernando Hevia wrote: The 6 Gb/s interface is capable of a maximum throughput of around 600 Mb/s. None of your drives can achieve that so I don't think you are limited to the interface speed. The 12 Gb/s interface speed advantage kicks in when there are several drives in

Re: HDD vs SSD without explanation

2018-01-15 Thread Neto pr
2018-01-15 17:58 GMT-08:00 Justin Pryzby : > On Mon, Jan 15, 2018 at 05:19:59PM -0800, Neto pr wrote: >> >> Can you reproduce the speed difference using dd ? >> >> time sudo dd if=/dev/sdX of=/dev/null bs=1M count=32K >> >> skip=$((128*$RANDOM/32)) # set bs to optimal_io_size >> > >> > Still I woul

Re: HDD vs SSD without explanation

2018-01-15 Thread Justin Pryzby
On Mon, Jan 15, 2018 at 05:19:59PM -0800, Neto pr wrote: > >> Can you reproduce the speed difference using dd ? > >> time sudo dd if=/dev/sdX of=/dev/null bs=1M count=32K > >> skip=$((128*$RANDOM/32)) # set bs to optimal_io_size > > > > Still I would have expected somewhat similar results in the ou

Re: HDD vs SSD without explanation

2018-01-15 Thread Neto pr
2018-01-15 16:18 GMT-08:00 Fernando Hevia : > > > 2018-01-15 20:25 GMT-03:00 Neto pr : >> >> 2018-01-15 17:55 GMT-02:00 Fernando Hevia : >> > >> > >> > 2018-01-15 15:32 GMT-03:00 Georg H. : >> >> >> >> >> >> Hello Neto >> >> >> >> Am 14.01.2018 um 21:44 schrieb Neto pr: >> >>> >> >>> Dear all >> >>

Re: HDD vs SSD without explanation

2018-01-15 Thread Fernando Hevia
2018-01-15 20:25 GMT-03:00 Neto pr : > 2018-01-15 17:55 GMT-02:00 Fernando Hevia : > > > > > > 2018-01-15 15:32 GMT-03:00 Georg H. : > >> > >> > >> Hello Neto > >> > >> Am 14.01.2018 um 21:44 schrieb Neto pr: > >>> > >>> Dear all > >>> > >>> Someone help me analyze the two execution plans below (E

Re: HDD vs SSD without explanation

2018-01-15 Thread Neto pr
2018-01-15 17:55 GMT-02:00 Fernando Hevia : > > > 2018-01-15 15:32 GMT-03:00 Georg H. : >> >> >> Hello Neto >> >> Am 14.01.2018 um 21:44 schrieb Neto pr: >>> >>> Dear all >>> >>> Someone help me analyze the two execution plans below (Explain ANALYZE >>> used), is the query 9 of TPC-H benchmark [1]

Re: HDD vs SSD without explanation

2018-01-15 Thread Neto pr
Hi Georg, Your answer I believe has revealed the real problem. I looked at the specification of my SATA SSD, and from my SAS HDD, I saw that the SAS has 12 Gb/s versus 6 Gb/s from the SSD SSD: Samsung 500 GB SATA III 6Gb/s - Model: 850 Evo http://www.samsung.com/semiconductor/minisite/ssd/product/

Re: HDD vs SSD without explanation

2018-01-15 Thread Fernando Hevia
2018-01-15 15:32 GMT-03:00 Georg H. : > > Hello Neto > > Am 14.01.2018 um 21:44 schrieb Neto pr: > >> Dear all >> >> Someone help me analyze the two execution plans below (Explain ANALYZE >> used), is the query 9 of TPC-H benchmark [1]. >> I'm using a server HP Intel Xeon 2.8GHz/4-core - Memory 8

Re: HDD vs SSD without explanation

2018-01-15 Thread Brian Busch
we've had the same experience here - with older SATA 2 (3Gbps) - in spite of SSD having no spin latency, the bus speed itself was half of the SAS-2 (6Gbps) we were using at the time which negated SSD perf in this area. HDD was about the same perf as SSD for us. Biran On Mon, Jan 15, 2018 at 1:32

Re: HDD vs SSD without explanation

2018-01-15 Thread Georg H.
Hello Neto Am 14.01.2018 um 21:44 schrieb Neto pr: Dear all Someone help me analyze the two execution plans below (Explain ANALYZE used), is the  query 9 of TPC-H benchmark [1]. I'm using a server HP Intel Xeon 2.8GHz/4-core - Memory 8GB HDD SAS 320GB 15 Krpm AND SSD Sansung EVO 500GB. My DB

Re: HDD vs SSD without explanation

2018-01-15 Thread Neto pr
2018-01-15 3:04 GMT-08:00 Neto pr : > 2018-01-14 19:09 GMT-08:00 Justin Pryzby : >> On Sun, Jan 14, 2018 at 06:25:40PM -0800, Neto pr wrote: >>> > The query plan is all garbled by mail , could you resend? Or post a link from >>> > https://explain.depesz.com/ >> >> On Sun, Jan 14, 2018 at 06:36:02P

Re: HDD vs SSD without explanation

2018-01-15 Thread Neto pr
2018-01-14 19:09 GMT-08:00 Justin Pryzby : > On Sun, Jan 14, 2018 at 06:25:40PM -0800, Neto pr wrote: >> > The query plan is all garbled by mail , could you resend? Or post a link >> > from >> > https://explain.depesz.com/ > > On Sun, Jan 14, 2018 at 06:36:02PM -0800, Neto pr wrote: >> I was not

Re: HDD vs SSD without explanation

2018-01-14 Thread Justin Pryzby
On Sun, Jan 14, 2018 at 06:25:40PM -0800, Neto pr wrote: > > The query plan is all garbled by mail , could you resend? Or post a link > > from > > https://explain.depesz.com/ On Sun, Jan 14, 2018 at 06:36:02PM -0800, Neto pr wrote: > I was not able to upload to the site, because I'm saving the e

Re: HDD vs SSD without explanation

2018-01-14 Thread Neto pr
2018-01-14 15:59 GMT-08:00 Neto pr : > Thanks for the reply. > I'll try upload the execution plan with Explain (analyse, buffer) for > website: https://explain.depesz.com/ > Below is a new execution plan, with Analyze, BUFFERS. This time, without changing anything in the configuration of the DBMS

Re: HDD vs SSD without explanation

2018-01-14 Thread Neto pr
2018-01-14 13:40 GMT-08:00 Justin Pryzby : > On Sun, Jan 14, 2018 at 12:44:00PM -0800, Neto pr wrote: >> Dear all >> >> Someone help me analyze the two execution plans below (Explain ANALYZE >> used), is the query 9 of TPC-H benchmark [1]. >> >> I'm using a server HP Intel Xeon 2.8GHz/4-core - Mem

Re: HDD vs SSD without explanation

2018-01-14 Thread Neto pr
Thanks for the reply. I'll try upload the execution plan with Explain (analyse, buffer) for website: https://explain.depesz.com/ I'm make an experiment for a scientific research and this is what I find strange, explaining better, strange HDD performance far outweigh the performance of an SSD. Do

Re: HDD vs SSD without explanation

2018-01-14 Thread Justin Pryzby
On Sun, Jan 14, 2018 at 12:44:00PM -0800, Neto pr wrote: > Dear all > > Someone help me analyze the two execution plans below (Explain ANALYZE > used), is the query 9 of TPC-H benchmark [1]. > > I'm using a server HP Intel Xeon 2.8GHz/4-core - Memory 8GB HDD SAS 320GB > 15 Krpm AND SSD Sansung EV

HDD vs SSD without explanation

2018-01-14 Thread Neto pr
Dear all Someone help me analyze the two execution plans below (Explain ANALYZE used), is the query 9 of TPC-H benchmark [1]. I'm using a server HP Intel Xeon 2.8GHz/4-core - Memory 8GB HDD SAS 320GB 15 Krpm AND SSD Sansung EVO 500GB. My DBMS parameters presents in postgresql.conf is default, but