public inbox for [email protected]  

help / color / mirror / Atom feed

From: Ilya Anfimov <[email protected]>
To: [email protected]
To: pgsql-hackers <[email protected]>
Subject: Re: Let's make PostgreSQL multi-threaded
Date: Thu, 8 Jun 2023 20:02:46 +0300
Message-ID: <[email protected]> (raw)
In-Reply-To: <CA+hUKG+kfGGT5DTSFse1+v+bcuUtTD4szNnvruTDscDXaF39Pw@mail.gmail.com>
References: <[email protected]>
	<[email protected]>
	<[email protected]>
	<CA+hUKG+kfGGT5DTSFse1+v+bcuUtTD4szNnvruTDscDXaF39Pw@mail.gmail.com>

On Wed, Jun 07, 2023 at 10:26:07AM +1200, Thomas Munro wrote:
> On Tue, Jun 6, 2023 at 6:52???AM Andrew Dunstan <[email protected]> wrote:
> > If we were starting out today we would probably choose a threaded implementation. But moving to threaded now seems to me like a multi-year-multi-person project with the prospect of years to come chasing bugs and the prospect of fairly modest advantages. The risk to reward doesn't look great.
> >
> > That's my initial reaction. I could be convinced otherwise.
> 
> Here is one thing I often think about when contemplating threads.
> Take a look at dsa.c.  It calls itself a shared memory allocator, but
> really it has two jobs, the second being to provide software emulation
> of virtual memory.  That???s behind dshash.c and now the stats system,
> and various parts of the parallel executor code.  It???s slow and
> complicated, and far from the state of the art.  I wrote that code
> (building on allocator code from Robert) with the expectation that it
> was a transitional solution to unblock a bunch of projects.  I always
> expected that we'd eventually be deleting it.  When I explain that
> subsystem to people who are not steeped in the lore of PostgreSQL, it
> sounds completely absurd.  I mean, ... it is, right?    My point is

 Isn't  all  the  memory operations would require nearly the same
shared memory allocators if someone switches to a threaded imple-
mentation?

> that we???re doing pretty unreasonable and inefficient contortions to
> develop new features -- we're not just happily chugging along without
> threads at no cost.
> 

view thread (43+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected]
  Subject: Re: Let's make PostgreSQL multi-threaded
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox