Re: pgsql: Add more SQL/JSON constructor functions

On Thu, Aug 22, 2024 at 11:02 jian he <jian(dot)universality(at)gmail(dot)com> wrote:

> On Tue, Jul 30, 2024 at 12:59 PM Amit Langote <amitlangote09(at)gmail(dot)com>
> wrote:
> >
> > Hi,
> >
> > On Fri, Jul 26, 2024 at 11:19 PM jian he <jian(dot)universality(at)gmail(dot)com>
> wrote:
> > > On Fri, Jul 26, 2024 at 4:53 PM Amit Langote <amitlangote09(at)gmail(dot)com>
> wrote:
> > > >
> > > >
> > > > Pushed 0003-0005 ahead of 0001-0002. Will try to push them over the
> > > > weekend. Rebased for now.
> >
> > Pushed them now.
> >
> > > {
> > > ...
> > > /*
> > > * For expression nodes that support soft errors. Should be set
> to NULL
> > > * before calling ExecInitExprRec() if the caller wants errors
> thrown.
> > > */
> > > ErrorSaveContext *escontext;
> > > } ExprState;
> > >
> > > i believe by default makeNode will set escontext to NULL.
> > > So the comment should be, if you want to catch the soft errors, make
> > > sure the escontext pointing to an allocated ErrorSaveContext.
> > > or maybe just say, default is NULL.
> > >
> > > Otherwise, the original comment's meaning feels like: we need to
> > > explicitly set it to NULL
> > > for certain operations, which I believe is false?
> >
> > OK, I'll look into updating this.
> >
> > > struct
> > > {
> > > Oid targettype;
> > > int32 targettypmod;
> > > bool omit_quotes;
> > > bool exists_coerce;
> > > bool exists_cast_to_int;
> > > bool check_domain;
> > > void *json_coercion_cache;
> > > ErrorSaveContext *escontext;
> > > } jsonexpr_coercion;
> > > do we need to comment that "check_domain" is only used for
> JSON_EXISTS_OP?
> >
> > I've renamed it to exists_check_domain and added a comment that
> > exists_* fields are relevant only for JSON_EXISTS_OP.
> >
> > > json_behavior_type:
> > > ERROR_P { $$ = JSON_BEHAVIOR_ERROR; }
> > > | NULL_P { $$ = JSON_BEHAVIOR_NULL; }
> > > | TRUE_P { $$ = JSON_BEHAVIOR_TRUE; }
> > > | FALSE_P { $$ = JSON_BEHAVIOR_FALSE; }
> > > | UNKNOWN { $$ = JSON_BEHAVIOR_UNKNOWN; }
> > > | EMPTY_P ARRAY { $$ = JSON_BEHAVIOR_EMPTY_ARRAY; }
> > > | EMPTY_P OBJECT_P { $$ = JSON_BEHAVIOR_EMPTY_OBJECT; }
> > > /* non-standard, for Oracle compatibility only */
> > > | EMPTY_P { $$ = JSON_BEHAVIOR_EMPTY_ARRAY; }
> > > ;
> > >
> > > EMPTY_P behaves the same as EMPTY_P ARRAY
> > > so for function GetJsonBehaviorConst, the following "case
> > > JSON_BEHAVIOR_EMPTY:" is wrong?
> > >
> > > case JSON_BEHAVIOR_NULL:
> > > case JSON_BEHAVIOR_UNKNOWN:
> > > case JSON_BEHAVIOR_EMPTY:
> > > val = (Datum) 0;
> > > isnull = true;
> > > typid = INT4OID;
> > > len = sizeof(int32);
> > > isbyval = true;
> > > break;
> > >
> > > also src/backend/utils/adt/ruleutils.c
> > > if (jexpr->on_error->btype != JSON_BEHAVIOR_EMPTY)
> > > get_json_behavior(jexpr->on_error, context, "ERROR");
> >
> > Something like the attached makes sense? While this meaningfully
> > changes the deparsing output, there is no behavior change for
> > JsonTable top-level path execution. That's because the behavior when
> > there's an error in the execution of the top-level path is to throw it
> > or return an empty set, which is handled in jsonpath_exec.c, not
> > execExprInterp.c.
> >
>
> hi amit.
> seems you forgot to attach the patch?

Yeah, I had planned to look at this after my vacation earlier this month,
but I context switched into working on another project and lost track of
this. I’ll make some time next week to fix whatever remains go be fixed
here. Thanks for the reminder.

>