Re: vary read_only in SPI calls? or poke at the on-entry snapshot?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Chapman Flack <chap(at)anastigmatix(dot)net>
Cc: PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: vary read_only in SPI calls? or poke at the on-entry snapshot?
Date: 2018-09-20 04:44:30
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

Chapman Flack <chap(at)anastigmatix(dot)net> writes:
> Would it be unprecedented / be unreasonable / break anything for the
> install_jar function to simply force a CommandCounterIncrement
> at the end of step 1 (after its temporary snapshot has been popped,
> so the former/on-entry ActiveSnapshot gets the increment)?

The risk you take there is changing the behavior of calling function(s).


> 1. fiddle the loader to always pass read_only => false to SPI calls,
> regardless of the volatility of the function it is loading for.
> 2. leave the loader alone, and adjust install_jar (an infrequent
> operation) to do something heretical with its on-entry snapshot.

I suspect #1 is less likely to have bad side-effects. But I've not
done any careful analysis.

regards, tom lane

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Andrey Lepikhov 2018-09-20 04:56:37 Re: Making all nbtree entries unique by having heap TIDs participate in comparisons
Previous Message Thomas Munro 2018-09-20 04:36:41 Re: infinite loop in parallel hash joins / DSA / get_best_segment