Re: PostgreSQL 12, JIT defaults - Mailing list pgsql-hackers

From Pavel Stehule
Subject Re: PostgreSQL 12, JIT defaults
Date
Msg-id CAFj8pRDzysbtMrwtp5zS0b6NDiZxbZ7d7hxeDJ1AWR2n8Du1gg@mail.gmail.com
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In response to Re: PostgreSQL 12, JIT defaults  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers


po 8. 10. 2018 v 17:22 odesílatel Andres Freund <andres@anarazel.de> napsal:


On October 8, 2018 8:16:06 AM PDT, Pavel Stehule <pavel.stehule@gmail.com> wrote:
>po 8. 10. 2018 v 17:10 odesílatel Andres Freund <andres@anarazel.de>
>napsal:
>
>>
>>
>> On October 8, 2018 8:03:56 AM PDT, Tom Lane <tgl@sss.pgh.pa.us>
>wrote:
>> >Andres Freund <andres@anarazel.de> writes:
>> >> Where is the jit=on coming from? Config from before it was turned
>> >off?
>> >
>> >A look in guc.c shows that jit defaults to "on" whether or not JIT
>is
>> >enabled at compile time.
>>
>> I thought Pavel was talking about 11 somehow...
>>
>
>I am sorry, It was not clear - I talked about master
>
>
>>
>> > This seems, at best, rather user-unfriendly.
>> >And it's not like our conventions for other compile-option-affected
>> >GUCs, eg the SSL ones.
>>
>> That was intentional, even though it perhaps should be better
>documented.
>> That allows a distro to build and distribute pg without llvm enabled,
>but
>> then have the JIT package with all the dependencies separately. The
>pg yum
>> packages do so.
>>
>
>I don't like this solution - it is safe on production - but it can
>breaks
>my development environment - or we need to change setup and make
>install
>will not be enough.

It's not clear what could be done about it. You'll run into other trouble if you have half installed build artifacts because you reconfigured. Make uninstall from before the reconfigure would uninstall it.

It is partially true - when I use wrong extension, then I got error message. But JIT library kills Postgres.

I expecting permanently disabled JIT if postgres was compiled without JIT support. Dependency on some external file doesn't looks like safe solution.


Andres
--
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