Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 04/28/2017 01:34 AM, Andres Freund wrote: On 2017-04-28 01:29:14 +0200, Tomas Vondra wrote: I can confirm this observation. I bought the Intel 750 NVMe SSD last year, the device has 1GB DDR3 cache on it (power-loss protected), can do ~1GB/s of sustained O_DIRECT sequential writes. But when

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 2017-04-28 01:29:14 +0200, Tomas Vondra wrote: > I can confirm this observation. I bought the Intel 750 NVMe SSD last year, > the device has 1GB DDR3 cache on it (power-loss protected), can do ~1GB/s of > sustained O_DIRECT sequential writes. But when running pgbench, I can't push > more than

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 04/27/2017 07:35 PM, Andres Freund wrote: On 2017-04-27 10:29:48 -0700, Joshua D. Drake wrote: On 04/27/2017 09:34 AM, Andres Freund wrote: On 2017-04-27 09:31:34 -0700, Joshua D. Drake wrote: On 04/27/2017 08:59 AM, Andres Freund wrote: I would agree it isn't yet a widespread issue.

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 04/27/2017 06:34 PM, Andres Freund wrote: On 2017-04-27 09:31:34 -0700, Joshua D. Drake wrote: On 04/27/2017 08:59 AM, Andres Freund wrote: Ok, based on the, few, answers I've got so far, my experience is indeed skewed. A number of the PG users I interacted with over the last couple years

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 2017-04-27 10:29:48 -0700, Joshua D. Drake wrote: > On 04/27/2017 09:34 AM, Andres Freund wrote: > > On 2017-04-27 09:31:34 -0700, Joshua D. Drake wrote: > > > On 04/27/2017 08:59 AM, Andres Freund wrote: > > > > > > > I would agree it isn't yet a widespread issue. > > > > I'm not yet sure

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 04/27/2017 09:34 AM, Andres Freund wrote: On 2017-04-27 09:31:34 -0700, Joshua D. Drake wrote: On 04/27/2017 08:59 AM, Andres Freund wrote: I would agree it isn't yet a widespread issue. I'm not yet sure about that actually. I suspect a large percentage of people with such workloads

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 2017-04-27 09:31:34 -0700, Joshua D. Drake wrote: > On 04/27/2017 08:59 AM, Andres Freund wrote: > > > > > Ok, based on the, few, answers I've got so far, my experience is indeed > > skewed. A number of the PG users I interacted with over the last couple > > years had WAL write ranges

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On 04/27/2017 08:59 AM, Andres Freund wrote: Ok, based on the, few, answers I've got so far, my experience is indeed skewed. A number of the PG users I interacted with over the last couple years had WAL write ranges somewhere in the range of 500MB/s to 2.2GB/s (max I'veseen). At that point

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

Hi, On 2017-04-24 21:17:43 -0700, Andres Freund wrote: > I've lately seen more and more installations where the generation of > write-ahead-log (WAL) is one of the primary bottlenecks. I'm curious > whether that's primarily a "sampling error" of mine, or whether that's > indeed more common. > >

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

On Tue, Apr 25, 2017 at 1:17 AM, Andres Freund wrote: > Questions (answer as many you can comfortably answer): > - How many MB/s, segments/s do you see on busier servers? ~20MB/s with FPW compression, with peaks of ~35MB/s. Writes become the bottleneck without compression and

Re: [GENERAL] [PERFORM] Questionaire: Common WAL write rates on busy servers.

Hi Andres. > 25 апр. 2017 г., в 7:17, Andres Freund написал(а): > > Hi, > > I've lately seen more and more installations where the generation of > write-ahead-log (WAL) is one of the primary bottlenecks. I'm curious > whether that's primarily a "sampling error" of mine, or