Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On Tue, Feb 16, 2016 at 7:10 AM, Tom Lane wrote: > Given this, I'm on board with just removing the weasel-wording about > timer resolution, except maybe for commit_delay where useful values > are small enough that it's a hazard on old systems. +1, but I'd move the guidance

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On Tue, Feb 16, 2016 at 12:06 AM, Robert Haas wrote: > On Wed, Feb 10, 2016 at 5:15 PM, Andres Freund wrote: >> Hi, >> >> Several places in our docs have blurbs like >>> Note that on many systems, the effective resolution of sleep delays is >>> 10

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

Robert Haas writes: > On Tue, Feb 16, 2016 at 3:50 AM, Andres Freund wrote: >> To back up my claim on this, read man 7 time >> (e.g. http://linux.die.net/man/7/time), especially "The software clock, >> HZ, and jiffies" and "High-resolution timers". To

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On Tue, Feb 16, 2016 at 3:50 AM, Andres Freund wrote: > On 2016-02-16 09:13:09 +0100, Andres Freund wrote: >> What we do we think the resolution is on modern >> >systems? I would not have guessed that to be inaccurate. >> >> Depends in a lot of factors. The biggest being how

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On 2016-02-16 09:13:09 +0100, Andres Freund wrote: > What we do we think the resolution is on modern > >systems? I would not have guessed that to be inaccurate. > > Depends in a lot of factors. The biggest being how busy you're system > is. On an mostly idle system (i.e. workout so CPUs being >

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On February 16, 2016 9:06:57 AM GMT+01:00, Robert Haas wrote: >On Wed, Feb 10, 2016 at 5:15 PM, Andres Freund >wrote: >> Hi, >> >> Several places in our docs have blurbs like >>> Note that on many systems, the effective resolution of sleep delays >is

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On Wed, Feb 10, 2016 at 5:15 PM, Andres Freund wrote: > Hi, > > Several places in our docs have blurbs like >> Note that on many systems, the effective resolution of sleep delays is >> 10 milliseconds; setting wal_writer_delay to a value that >> is not a multiple of 10 might

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On February 16, 2016 3:09:16 AM GMT+01:00, Merlin Moncure >I guess we should probably explain what is actually happening, namely >that the precise sleep duration is delegated to the operating system >scheduler which may cause the process to sleep longer than requested. In not really seeing why:

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On Wed, Feb 10, 2016 at 4:15 PM, Andres Freund wrote: > Hi, > > Several places in our docs have blurbs like >> Note that on many systems, the effective resolution of sleep delays is >> 10 milliseconds; setting wal_writer_delay to a value that >> is not a multiple of 10 might

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On Mon, Feb 15, 2016 at 11:23 AM, Peter Geoghegan wrote: > commit_delay doesn't have any guidance like this, where it could > certainly matter, because optimal settings are rarely greater than 10 > milliseconds. Actually, it does, but it's in "29.4. WAL Configuration", not next

Re: [HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

On Wed, Feb 10, 2016 at 2:15 PM, Andres Freund wrote: > Afaik that's not the case on any recent operating system/hardware. So > perhaps we should just remove all of those blurbs, or just replace them > with something like "on some older systems the effective resolution of >

[HACKERS] Remove or weaken hints about "effective resolution of sleep delays is 10 ms"?

Hi, Several places in our docs have blurbs like > Note that on many systems, the effective resolution of sleep delays is > 10 milliseconds; setting wal_writer_delay to a value that > is not a multiple of 10 might have the same results as setting it to > the next higher multiple of 10. Afaik