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help / color / mirror / Atom feedFrom: Andres Freund <[email protected]>
To: Melanie Plageman <[email protected]>
Cc: [email protected]
Cc: Thomas Munro <[email protected]>
Cc: Peter Geoghegan <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: Nazir Bilal Yavuz <[email protected]>
Subject: Re: AIO / read stream heuristics adjustments for index prefetching
Date: Fri, 3 Apr 2026 16:41:18 -0400
Message-ID: <q46tgxvdbqvbhsvrkgaod7la3jbbecjitpwanwse3jeu4ervdr@z3zqxlcxcgtd> (raw)
In-Reply-To: <CAAKRu_b+tymZQc2vv__k8oPHsVQppg9QmaeQLiupZ3t2AO=z3A@mail.gmail.com>
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<CAAKRu_b+tymZQc2vv__k8oPHsVQppg9QmaeQLiupZ3t2AO=z3A@mail.gmail.com>
Hi,
Forgot to send this one earlier:
On 2026-04-03 11:46:59 -0400, Melanie Plageman wrote:
> On Thu, Apr 2, 2026 at 11:47 AM Andres Freund <[email protected]> wrote:
> >
> > What do you think about the updated patch to achieve that that I posted?
>
> here is some review on 0005 and 0006 earlier posted
> concrete things:
> -------
> - I’d reorder stream→distance == 0 in read_stream_look_ahead() (and
> issue), I found myself asking why it wasn’t first
It'd not be correct in should_issue_now(). We can't move it before
/* there is no pending IO that could be issued */
if (pending_read_nblocks == 0)
return false;
because then we'd trigger a call to read_stream_start_pending_read(), without
there being a pending read.
We can't move it before
/* never start more IOs than our cap */
if (stream->ios_in_progress >= stream->max_ios)
return false;
because that could lead us to exceeding max_ios.
Greetings,
Andres Freund
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Subject: Re: AIO / read stream heuristics adjustments for index prefetching
In-Reply-To: <q46tgxvdbqvbhsvrkgaod7la3jbbecjitpwanwse3jeu4ervdr@z3zqxlcxcgtd>
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