| From: | Michael Paquier <michael(at)paquier(dot)xyz> |
|---|---|
| To: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Cc: | "tsunakawa(dot)takay(at)fujitsu(dot)com" <tsunakawa(dot)takay(at)fujitsu(dot)com>, "osumi(dot)takamichi(at)fujitsu(dot)com" <osumi(dot)takamichi(at)fujitsu(dot)com>, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>, "sawada(dot)mshk(at)gmail(dot)com" <sawada(dot)mshk(at)gmail(dot)com>, "masao(dot)fujii(at)oss(dot)nttdata(dot)com" <masao(dot)fujii(at)oss(dot)nttdata(dot)com>, "laurenz(dot)albe(at)cybertec(dot)at" <laurenz(dot)albe(at)cybertec(dot)at>, "ashutosh(dot)bapat(dot)oss(at)gmail(dot)com" <ashutosh(dot)bapat(dot)oss(at)gmail(dot)com>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: Disable WAL logging to speed up data loading |
| Date: | 2020-12-30 13:04:41 |
| Message-ID: | X+x66SzrQmGk+Ysy@paquier.xyz |
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| Lists: | pgsql-hackers |
On Mon, Dec 28, 2020 at 11:06:30AM +0000, Simon Riggs wrote:
> Agreed, it is a footgun. -1 to commit the patch as-is.
>
> The patch to avoid WAL is simple but it is dangerous for both the user
> and the PostgreSQL project.
Something that has not been mentioned on this thread is that if you
could also put pg_wal/ on a RAM disk. That's similarly unsafe, of
course, but it does not require any extra upstream patching, and that
should be really fast for the case of this thread. If you care about
consistency, there are solutions like PMEM that we could look more
into.
> In my experience, people will use this option and when it crashes and
> they lose their data, they will claim PostgreSQL broke and that they
> were not stupid enough to use this option. Data loss has always been
> the most serious error for PostgreSQL and our reputation for
> protecting data has been hard won; it can easily be lost in a moment
> of madness. Please consider how the headlines will read, bearing in
> mind past incidents and negative press.
Yeah..
> Yes, we did think of this feature already and rejected it.
I don't recall seeing such a discussion. Do you have some references?
Just a matter of curiosity :)
--
Michael
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