Re: effective_io_concurrency's steampunk spindle maths - Mailing list pgsql-hackers

From Thomas Munro
Subject Re: effective_io_concurrency's steampunk spindle maths
Date
Msg-id CA+hUKGJu-sJepbDeamK+c3XWXO2jQHL=8pxTphVtWO93i1Awrg@mail.gmail.com
Whole thread Raw
In response to Re: effective_io_concurrency's steampunk spindle maths  (Evgeniy Shishkin <itparanoia@gmail.com>)
List pgsql-hackers
On Sat, Mar 7, 2020 at 11:54 PM Evgeniy Shishkin <itparanoia@gmail.com> wrote:
> > On Mar 7, 2020, at 00:33, Thomas Munro <thomas.munro@gmail.com> 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 overall I/O capacity available to InnoDB. It should be set to
approximatelythe number of I/O operations that the system can perform per second (IOPS). When innodb_io_capacity is
set,InnoDB estimates the I/O bandwidth available for background tasks based on the set value. 
> >
>
> Perhaps we can have maintenance_io_capacity as well.

That sounds like total I/O capacity for your system that will be
shared out for various tasks, which would definitely be nice to have,
but here we're talking about a simpler per-operation settings.  What
we have is a bit like work_mem (a memory limit used for each
individual hash, sort, tuplestore, ...), compared to a hypothetical
whole-system memory budget (which would definitely also be nice to
have).



pgsql-hackers by date:

Previous
From: David Rowley
Date:
Subject: Re: [PATCH] Erase the distinctClause if the result is unique by definition
Next
From: Andres Freund
Date:
Subject: Re: Nicer error when connecting to standby with hot_standby=off