Re: Row pattern recognition

Hi.

More review based on https://github.com/assam258-5892/postgres/commits/RPR

remove_unused_subquery_outputs
``````
if (dvar->varno == var->varno &&
dvar->varattno == var->varattno &&
dvar->varlevelsup == var->varlevelsup)
{
needed_by_define = true;
break;
}
``````
dvar, var both can be whole-row Vars, but this seems to work for whole-row vars.
We need some simple regress tests for cases where both are whole-row
vars or one of them is a whole-row var.

I've attached a patch with some refactoring. The below is detailed
commit message.
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RPRNavExpr->resulttype should also marked as pg_node_attr(query_jumble_ignore)

collectPatternVariables is not needed.
The parser already ensures every DEFINE variable appears in PATTERN,
so there is nothing to filter.
Also, we don't really do anything special (like make a dummy Const) regarding
PATTERN variables that not appearing in the DEFINE clause.
See nfa_evaluate_row the for loop break.

buildDefineVariableList is trivial. No need to export it as an
external function.

Rename WindowAggState.defineClauseList to defineClauseExprs
Minor refactoring of regress test comments.
Flatten a needlessly nested block in show_window_def().
Replace a post-loop ListCell NULL check in
remove_unused_subquery_outputs() with a boolean flag.
Reduce the number of arguments in make_windowagg.
--------------------------------------------------------------------

--
jian
https://www.enterprisedb.com/