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About asynchronous I/O
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* About asynchronous I/O
@ 2026-06-23 07:55 ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  0 siblings, 1 reply; 9+ messages in thread

From: ek ek @ 2026-06-23 07:55 UTC (permalink / raw)
  To: Pgsql-admin <[email protected]>

Hello everyone,
Are any of you running PostgreSQL 18 on production environments sized
between 1 to 3TB? Does the 'asynchronous I/O (AIO) subsystem' deliver a
significant performance increase? Also, has anyone had the opportunity to
benchmark it against v17?


^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
@ 2026-06-23 11:25 ` bertrand HARTWIG <[email protected]>
  2026-06-23 12:02   ` Re: About asynchronous I/O Ron Johnson <[email protected]>
  0 siblings, 1 reply; 9+ messages in thread

From: bertrand HARTWIG @ 2026-06-23 11:25 UTC (permalink / raw)
  To: ek ek <[email protected]>; +Cc: Pgsql-admin <[email protected]>

Hello,

The size of the database is clearly not important.

What matters are queries that are not already cached and that perform I/O.

With async I/O, you can see I/O performance improvements of up to 200%–300%. The higher the disk latency, the greater the gains you will notice.

Regards,

Bertrand


> Le 23 juin 2026 à 09:55, ek ek <[email protected]> a écrit :
> 
> Hello everyone,
> Are any of you running PostgreSQL 18 on production environments sized between 1 to 3TB? Does the 'asynchronous I/O (AIO) subsystem' deliver a significant performance increase? Also, has anyone had the opportunity to benchmark it against v17?



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
@ 2026-06-23 12:02   ` Ron Johnson <[email protected]>
  2026-06-23 12:19     ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  0 siblings, 1 reply; 9+ messages in thread

From: Ron Johnson @ 2026-06-23 12:02 UTC (permalink / raw)
  To: Pgsql-admin <[email protected]>

On Tue, Jun 23, 2026 at 7:26 AM bertrand HARTWIG <[email protected]>
wrote:

> Hello,
>
> The size of the database is clearly not important.
>
> What matters are queries that are not already cached and that perform I/O.
>
> With async I/O, you can see I/O performance improvements of up to
> 200%–300%. The higher the disk latency, the greater the gains you will
> notice.
>

So, not so useful on SSD/NVMe?


> Regards,
>
> Bertrand
>
> Le 23 juin 2026 à 09:55, ek ek <[email protected]> a écrit :
>
> Hello everyone,
> Are any of you running PostgreSQL 18 on production environments sized
> between 1 to 3TB? Does the 'asynchronous I/O (AIO) subsystem' deliver a
> significant performance increase? Also, has anyone had the opportunity to
> benchmark it against v17?
>
>
>

-- 
Death to <Redacted>, and butter sauce.
Don't boil me, I'm still alive.
<Redacted> lobster!


^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 12:02   ` Re: About asynchronous I/O Ron Johnson <[email protected]>
@ 2026-06-23 12:19     ` bertrand HARTWIG <[email protected]>
  2026-06-23 13:04       ` Re: About asynchronous I/O JOHN WIENCEK <[email protected]>
  0 siblings, 1 reply; 9+ messages in thread

From: bertrand HARTWIG @ 2026-06-23 12:19 UTC (permalink / raw)
  To: Ron Johnson <[email protected]>; +Cc: Pgsql-admin <[email protected]>

Very usefull on SSD AND nvme ! (low latency on IOPs). But the higher the disk latency, the greater the gains you will notice.

On SSD i observed 200%

> Le 23 juin 2026 à 14:02, Ron Johnson <[email protected]> a écrit :
> 
> On Tue, Jun 23, 2026 at 7:26 AM bertrand HARTWIG <[email protected] <mailto:[email protected]>> wrote:
>> Hello,
>> 
>> The size of the database is clearly not important.
>> 
>> What matters are queries that are not already cached and that perform I/O.
>> 
>> With async I/O, you can see I/O performance improvements of up to 200%–300%. The higher the disk latency, the greater the gains you will notice.
>> 
> 
> So, not so useful on SSD/NVMe?
>  
>> Regards,
>> 
>> Bertrand
>> 
>> 
>>> Le 23 juin 2026 à 09:55, ek ek <[email protected] <mailto:[email protected]>> a écrit :
>>> 
>>> Hello everyone,
>>> Are any of you running PostgreSQL 18 on production environments sized between 1 to 3TB? Does the 'asynchronous I/O (AIO) subsystem' deliver a significant performance increase? Also, has anyone had the opportunity to benchmark it against v17?
>> 
> 
> 
> 
> --
> Death to <Redacted>, and butter sauce.
> Don't boil me, I'm still alive.
> <Redacted> lobster!



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 12:02   ` Re: About asynchronous I/O Ron Johnson <[email protected]>
  2026-06-23 12:19     ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
@ 2026-06-23 13:04       ` JOHN WIENCEK <[email protected]>
  2026-06-23 13:35         ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 13:58         ` Re: About asynchronous I/O Scott Ribe <[email protected]>
  0 siblings, 2 replies; 9+ messages in thread

From: JOHN WIENCEK @ 2026-06-23 13:04 UTC (permalink / raw)
  To: bertrand HARTWIG <[email protected]>; Ron Johnson <[email protected]>; +Cc: Pgsql-admin <[email protected]>

Can your application assume the risk of lost transactions in the event of a database crash?
ASYNC/IO is not a good solution for all applications.


Regards

John

> On 06/23/2026 7:19 AM CDT bertrand HARTWIG <[email protected]> wrote:
>  
>  
> Very usefull on SSD AND nvme ! (low latency on IOPs). But the higher the disk latency, the greater the gains you will notice.
>  
> On SSD i observed 200%
> 
> 
> > Le 23 juin 2026 à 14:02, Ron Johnson <[email protected]> a écrit :
> > On Tue, Jun 23, 2026 at 7:26 AM bertrand HARTWIG <[email protected] mailto:[email protected]> wrote:
> > 
> > > 
> > > Hello,
> > > 
> > > The size of the database is clearly not important.
> > > 
> > > What matters are queries that are not already cached and that perform I/O.
> > > 
> > > With async I/O, you can see I/O performance improvements of up to 200%–300%. The higher the disk latency, the greater the gains you will notice.
> > > 
> >  
> > So, not so useful on SSD/NVMe?
> >  
> > 
> > > 
> > > Regards,
> > > 
> > > Bertrand
> > > 
> > > 
> > > > Le 23 juin 2026 à 09:55, ek ek <[email protected] mailto:[email protected]> a écrit :
> > > > 
> > > > Hello everyone,
> > > > Are any of you running PostgreSQL 18 on production environments sized between 1 to 3TB? Does the 'asynchronous I/O (AIO) subsystem' deliver a significant performance increase? Also, has anyone had the opportunity to benchmark it against v17?
> > > > 
> > > 
> >  
> >  
> > --
> > Death to <Redacted>, and butter sauce.
> > Don't boil me, I'm still alive.
> > <Redacted> lobster!
> > 
> 


^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 12:02   ` Re: About asynchronous I/O Ron Johnson <[email protected]>
  2026-06-23 12:19     ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 13:04       ` Re: About asynchronous I/O JOHN WIENCEK <[email protected]>
@ 2026-06-23 13:35         ` bertrand HARTWIG <[email protected]>
  1 sibling, 0 replies; 9+ messages in thread

From: bertrand HARTWIG @ 2026-06-23 13:35 UTC (permalink / raw)
  To: JOHN WIENCEK <[email protected]>; +Cc: Ron Johnson <[email protected]>; Pgsql-admin <[email protected]>

Linux Io_uring is used by PostgreSQL only with aio_read() …


> Le 23 juin 2026 à 15:04, JOHN WIENCEK <[email protected]> a écrit :
> 
> Can your application assume the risk of lost transactions in the event of a database crash?
> ASYNC/IO is not a good solution for all applications.
> 
> 
> Regards
> 
> John
>> On 06/23/2026 7:19 AM CDT bertrand HARTWIG <[email protected]> wrote:
>>  
>>  
>> Very usefull on SSD AND nvme ! (low latency on IOPs). But the higher the disk latency, the greater the gains you will notice.
>>  
>> On SSD i observed 200%
>> 
>>> Le 23 juin 2026 à 14:02, Ron Johnson <[email protected]> a écrit :
>>> On Tue, Jun 23, 2026 at 7:26 AM bertrand HARTWIG <[email protected] <mailto:[email protected]>> wrote:
>>> Hello,
>>> 
>>> The size of the database is clearly not important.
>>> 
>>> What matters are queries that are not already cached and that perform I/O.
>>> 
>>> With async I/O, you can see I/O performance improvements of up to 200%–300%. The higher the disk latency, the greater the gains you will notice.
>>> 
>>>  
>>> So, not so useful on SSD/NVMe?
>>>  
>>> Regards,
>>> 
>>> Bertrand
>>> 
>>> 
>>>> Le 23 juin 2026 à 09:55, ek ek <[email protected] <mailto:[email protected]>> a écrit :
>>>> 
>>>> Hello everyone,
>>>> Are any of you running PostgreSQL 18 on production environments sized between 1 to 3TB? Does the 'asynchronous I/O (AIO) subsystem' deliver a significant performance increase? Also, has anyone had the opportunity to benchmark it against v17?
>>> 
>>>  
>>>  
>>> --
>>> Death to <Redacted>, and butter sauce.
>>> Don't boil me, I'm still alive.
>>> <Redacted> lobster!



^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 12:02   ` Re: About asynchronous I/O Ron Johnson <[email protected]>
  2026-06-23 12:19     ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 13:04       ` Re: About asynchronous I/O JOHN WIENCEK <[email protected]>
@ 2026-06-23 13:58         ` Scott Ribe <[email protected]>
  2026-06-23 14:05           ` Re: About asynchronous I/O Ron Johnson <[email protected]>
  1 sibling, 1 reply; 9+ messages in thread

From: Scott Ribe @ 2026-06-23 13:58 UTC (permalink / raw)
  To: JOHN WIENCEK <[email protected]>; +Cc: bertrand HARTWIG <[email protected]>; Ron Johnson <[email protected]>; Pgsql-admin <[email protected]>

On Jun 23, 2026, at 7:04 AM, JOHN WIENCEK <[email protected]> wrote:
> 
> Can your application assume the risk of lost transactions in the event of a database crash?

Pretty sure that's not a risk here...






^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 12:02   ` Re: About asynchronous I/O Ron Johnson <[email protected]>
  2026-06-23 12:19     ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 13:04       ` Re: About asynchronous I/O JOHN WIENCEK <[email protected]>
  2026-06-23 13:58         ` Re: About asynchronous I/O Scott Ribe <[email protected]>
@ 2026-06-23 14:05           ` Ron Johnson <[email protected]>
  2026-06-23 14:19             ` Re: About asynchronous I/O Michael Banck <[email protected]>
  0 siblings, 1 reply; 9+ messages in thread

From: Ron Johnson @ 2026-06-23 14:05 UTC (permalink / raw)
  To: Pgsql-admin <[email protected]>

On Tue, Jun 23, 2026 at 9:59 AM Scott Ribe <[email protected]>
wrote:

> On Jun 23, 2026, at 7:04 AM, JOHN WIENCEK <[email protected]> wrote:
> >
> > Can your application assume the risk of lost transactions in the event
> of a database crash?
>
> Pretty sure that's not a risk here...
>

Because WAL writing is sync io?

-- 
Death to <Redacted>, and butter sauce.
Don't boil me, I'm still alive.
<Redacted> lobster!


^ permalink  raw  reply  [nested|flat] 9+ messages in thread

* Re: About asynchronous I/O
  2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
  2026-06-23 11:25 ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 12:02   ` Re: About asynchronous I/O Ron Johnson <[email protected]>
  2026-06-23 12:19     ` Re: About asynchronous I/O bertrand HARTWIG <[email protected]>
  2026-06-23 13:04       ` Re: About asynchronous I/O JOHN WIENCEK <[email protected]>
  2026-06-23 13:58         ` Re: About asynchronous I/O Scott Ribe <[email protected]>
  2026-06-23 14:05           ` Re: About asynchronous I/O Ron Johnson <[email protected]>
@ 2026-06-23 14:19             ` Michael Banck <[email protected]>
  0 siblings, 0 replies; 9+ messages in thread

From: Michael Banck @ 2026-06-23 14:19 UTC (permalink / raw)
  To: Ron Johnson <[email protected]>; +Cc: Pgsql-admin <[email protected]>

On Tue, Jun 23, 2026 at 10:05:42AM -0400, Ron Johnson wrote:
> On Tue, Jun 23, 2026 at 9:59 AM Scott Ribe <[email protected]>
> wrote:
> > On Jun 23, 2026, at 7:04 AM, JOHN WIENCEK <[email protected]> wrote:
> > > Can your application assume the risk of lost transactions in the event
> > of a database crash?
> >
> > Pretty sure that's not a risk here...
> 
> Because WAL writing is sync io?

That, and because AIO is read-only in Postgres so far (including in the
upcoming PG19).


Michael






^ permalink  raw  reply  [nested|flat] 9+ messages in thread


end of thread, other threads:[~2026-06-23 14:19 UTC | newest]

Thread overview: 9+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2026-06-23 07:55 About asynchronous I/O ek ek <[email protected]>
2026-06-23 11:25 ` bertrand HARTWIG <[email protected]>
2026-06-23 12:02   ` Ron Johnson <[email protected]>
2026-06-23 12:19     ` bertrand HARTWIG <[email protected]>
2026-06-23 13:04       ` JOHN WIENCEK <[email protected]>
2026-06-23 13:35         ` bertrand HARTWIG <[email protected]>
2026-06-23 13:58         ` Scott Ribe <[email protected]>
2026-06-23 14:05           ` Ron Johnson <[email protected]>
2026-06-23 14:19             ` Michael Banck <[email protected]>

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