Re: effective_io_concurrency's steampunk spindle maths

2020-05-14 Thread Thomas Munro
On Wed, May 13, 2020 at 6:58 AM Peter Geoghegan wrote: > Shouldn't you close out the "Should we rename > effective_io_concurrency?" Postgres 13 open item now? Yeah, that doesn't really seem worth the churn. I'll move it to the resolved list in a day or two if no one shows up to argue for a

Re: effective_io_concurrency's steampunk spindle maths

2020-05-12 Thread Peter Geoghegan
On Sun, Mar 15, 2020 at 9:27 PM Thomas Munro wrote: > On Tue, Mar 10, 2020 at 12:20 PM Thomas Munro wrote: > > Here's a patch set to remove the spindle stuff, add a maintenance > > variant, and use the maintenance one in > > heap_compute_xid_horizon_for_tuples(). > > Pushed. Shouldn't you close

Re: effective_io_concurrency's steampunk spindle maths

2020-03-15 Thread Thomas Munro
On Tue, Mar 10, 2020 at 12:20 PM Thomas Munro wrote: > Here's a patch set to remove the spindle stuff, add a maintenance > variant, and use the maintenance one in > heap_compute_xid_horizon_for_tuples(). Pushed.

Re: effective_io_concurrency's steampunk spindle maths

2020-03-09 Thread Thomas Munro
On Sat, Mar 7, 2020 at 9:07 AM Tom Lane wrote: > Tomas Vondra writes: > > So I think we should either rename e_i_c or keep it as is, and then also > > have a new GUC. And then translate the values between those (but that > > might be overkill). > > Please DON'T try to have two interrelated GUCs

Re: effective_io_concurrency's steampunk spindle maths

2020-03-09 Thread Thomas Munro
On Sat, Mar 7, 2020 at 11:54 PM Evgeniy Shishkin wrote: > > On Mar 7, 2020, at 00:33, Thomas Munro wrote: > > That is indeed what led me to start thinking about what a good new > > name would be. > > MySQL has a term io_capacity. >

Re: effective_io_concurrency's steampunk spindle maths

2020-03-07 Thread Evgeniy Shishkin
> On Mar 7, 2020, at 00:33, Thomas Munro wrote: > > That is indeed what led me to start thinking about what a good new > name would be. MySQL has a term io_capacity. https://dev.mysql.com/doc/refman/8.0/en/innodb-configuring-io-capacity.html > The innodb_io_capacity variable defines the

Re: effective_io_concurrency's steampunk spindle maths

2020-03-06 Thread Thomas Munro
On Sat, Mar 7, 2020 at 8:35 AM Tomas Vondra wrote: > I think the main issue with keeping the current GUC name is that if you > had a value that worked, we'll silently interpret it differently. Which > is a bit annoying :-( Yeah. Perhaps we should just give the formula for translating v12

Re: effective_io_concurrency's steampunk spindle maths

2020-03-06 Thread Thomas Munro
On Sat, Mar 7, 2020 at 8:00 AM Andres Freund wrote: > On 2020-03-02 18:28:41 +1300, Thomas Munro wrote: > > * leaves room for a different setting for sequential prefetching > > I think if we want to split those at some point, we ought to split it if > we have a good reason, not before. It's not

Re: effective_io_concurrency's steampunk spindle maths

2020-03-06 Thread Thomas Munro
On Sat, Mar 7, 2020 at 9:52 AM Michael Banck wrote: > On Mon, Mar 02, 2020 at 06:28:41PM +1300, Thomas Munro wrote: > > * "maintenance_" prefix is like other GUCs that establish (presumably > > larger) limits for processes working on behalf of many user sessions > > I'm a bit skeptical about this

Re: effective_io_concurrency's steampunk spindle maths

2020-03-06 Thread Michael Banck
Hi, On Mon, Mar 02, 2020 at 06:28:41PM +1300, Thomas Munro wrote: > Should we rename it? Here are my first suggestions: > > maintenance_random_page_prefetch_degree > > Rationale for this naming pattern: [...] > * "maintenance_" prefix is like other GUCs that establish (presumably > larger)

Re: effective_io_concurrency's steampunk spindle maths

2020-03-06 Thread Tom Lane
Tomas Vondra writes: > So I think we should either rename e_i_c or keep it as is, and then also > have a new GUC. And then translate the values between those (but that > might be overkill). Please DON'T try to have two interrelated GUCs for this. We learned our lesson about that years ago. I

Re: effective_io_concurrency's steampunk spindle maths

2020-03-06 Thread Tomas Vondra
On Fri, Mar 06, 2020 at 10:05:13AM -0800, Andres Freund wrote: Hi, On 2020-03-02 18:28:41 +1300, Thomas Munro wrote: I was reading through some old threads[1][2][3] while trying to figure out how to add a new GUC to control I/O prefetching for new kinds of things[4][5], and enjoyed Simon

Re: effective_io_concurrency's steampunk spindle maths

2020-03-06 Thread Andres Freund
Hi, On 2020-03-02 18:28:41 +1300, Thomas Munro wrote: > I was reading through some old threads[1][2][3] while trying to figure > out how to add a new GUC to control I/O prefetching for new kinds of > things[4][5], and enjoyed Simon Riggs' reference to Jules Verne in the > context of RAID

effective_io_concurrency's steampunk spindle maths

2020-03-01 Thread Thomas Munro
Hello, I was reading through some old threads[1][2][3] while trying to figure out how to add a new GUC to control I/O prefetching for new kinds of things[4][5], and enjoyed Simon Riggs' reference to Jules Verne in the context of RAID spindles. On 2 Sep 2015 14:54, "Andres Freund" wrote: > > On