Re: PG 15 (and to a smaller degree 14) regression due to ExprEvalStep size

On Thu, Jul 21, 2022 at 11:55 PM Amit Langote <amitlangote09(at)gmail(dot)com>
wrote:
> On Wed, Jul 20, 2022 at 11:09 PM Amit Langote <amitlangote09(at)gmail(dot)com>
wrote:
> > On Wed, Jul 20, 2022 at 12:37 AM Andres Freund <andres(at)anarazel(dot)de>
wrote:
> > > On 2022-07-19 20:40:11 +0900, Amit Langote wrote:
> > > > About that, I was wondering if the blocks in llvm_compile_expr()
need
> > > > to be hand-coded to match what's added in ExecInterpExpr() or if
I've
> > > > missed some tool that can be used instead?
> > >
> > > The easiest way is to just call an external function for the
implementation of
> > > the step. But yes, otherwise you need to handcraft it.
> >
> > Ok, thanks.
> >
> > So I started updating llvm_compile_expr() for handling the new
> > ExprEvalSteps that the patch adds to ExecExprInterp(), but quickly
> > realized that code could have been consolidated into less code, or
> > IOW, into fewer new ExprEvalSteps. So, I refactored things that way
> > and am now retrying adding the code to llvm_compile_expr() based on
> > new, better consolidated, code.
> >
> > Here's the updated version, without the llvm pieces, in case you'd
> > like to look at it even in this state. I'll post a version with llvm
> > pieces filled in tomorrow. (I have merged the different patches into
> > one for convenience.)
>
> And here's a version with llvm pieces filled in.
>
> Because I wrote all of it while not really understanding how the LLVM
> constructs like blocks and branches work, the only reason I think
> those llvm_compile_expr() additions may be correct is that all the
> tests in jsonb_sqljson.sql pass even if I add the following line at
> the top:
>
> set jit_above_cost to 0;

Oh and I did build --with-llvm. :-)

--
Thanks, Amit Langote
EDB: http://www.enterprisedb.com
--
Thanks, Amit Langote
EDB: http://www.enterprisedb.com