On 2016/11/24 16:46, Ashutosh Bapat wrote:
Sorry. I think the current version is better than previous one. The term "subselect alias" is confusing in the previous version. In the current version, "Get the relation and column alias for a given Var node," we need to add word "identifiers" like "Get the relation and column identifiers for a given Var node".
I wrote:
OK, but one thing I'm concerned about is the term "relation alias" seems a bit confusing because we already used the term for the alias of the form "rN". To avoid that, how about saying "table alias", not "relation alias"? (in which case, the comment would be something like "Get the table and column identifiers for a given Var node".)
table will be misleading as subquery can represent a join and corresponding alias would represent the join. Relation is better term.
But the documentation uses the word "table" for a join relation. See 7.2.1.2. Table and Column Aliases:
https://www.postgresql.org/docs/9.6/static/queries-table-expressions.html#QUERIES-TABLE-ALIASES
I don't think so; in the current version, we essentially deparse from and search into the same object, ie, foreignrel->reltarget->exprs, since the tlist created by build_tlist_to_deparse is build from the foreignrel->reltarget->exprs. Also, since it is just created for deparsing the relation as a subquery in deparseRangeTblRef and isn't stored into fpinfo or anywhere alse, we would need no concern about creating such avenues. IMO I think adding comments would be enough for this.
build_tlist_to_depase() calls pull_var_nodes() before creating the tlist, whereas the code that searches does not do that. Code-wise those are not the same things.
You missed the point; the foreignrel->reltarget->exprs doesn't contain any PHVs, so the tlist created by build_tlist_to_depase will be guaranteed to be one-to-one with the foreignrel->reltarget->exprs.
Best regards, Etsuro Fujita -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
