Re: POC, WIP: OR-clause support for indexes

On Mon, Aug 26, 2024 at 6:41 PM Alena Rybakina
<a(dot)rybakina(at)postgrespro(dot)ru> wrote:
>
> + /* Construct the list of nested OR arguments */
> + for (j = group_start; j < i; j++)
> + {
> + Node *arg = list_nth(orargs, matches[j].argindex);
> +
> + rargs = lappend(rargs, arg);
> + if (IsA(arg, RestrictInfo))
> + args = lappend(args, ((RestrictInfo *) arg)->clause);
> + else
> + args = lappend(args, arg);
> + }
> the ELSE branch never reached?
>
> Reached - if your arg is BoolExpr type, for example if it consists "And" expressions.
>
I added elog(INFO, "this part called");
all the tests still passed, that's where my confusion comes from.

>
> +/*
> + * Data structure representing information about OR-clause argument and its
> + * matching index key. Used for grouping of similar OR-clause arguments in
> + * group_similar_or_args().
> + */
> +typedef struct
> +{
> + int indexnum; /* index of the matching index */
> + int colnum; /* index of the matching column */
> + Oid opno; /* OID of the OpClause operator */
> + Oid inputcollid; /* OID of the OpClause input collation */
> + int argindex; /* index of the clause in the list of
> + * arguments */
> +} OrArgIndexMatch;
>
> I am not 100% sure about the comments.
> indexnum: index of the matching index reside in rel->indexlist that
> matches (counting from 0)
> colnum: the column number of the matched index (counting from 0)
>
> To be honest, I'm not sure that I completely understand your point here.
>
I guess I want to make the comments more explicit, straightforward.

does match_orclause_to_indexcol have a memory issue.
current match_orclause_to_indexcol pattern is
<<<<<<<<<<<<<<<<<<
foreach(lc, orclause->args)
{
condition check, if fail, return null.
consts = lappend(consts, constExpr);
}
if (have_param)
{
ArrayExpr *arrayExpr = makeNode(ArrayExpr);
arrayExpr->elements = consts;
}
else
{
do other work.
list_free(consts);
}
<<<<<<<<<<<<<<<<<<
if have_param is false, first foreach fail at the last iteration
then
"list_free(consts);" will not get called?
Will it be a problem?