jrgemignani commented on code in PR #2295:
URL: https://github.com/apache/age/pull/2295#discussion_r2654166684
##########
src/backend/parser/cypher_clause.c:
##########
@@ -6410,6 +6427,273 @@ transform_cypher_clause_as_subquery(cypher_parsestate
*cpstate,
return pnsi;
}
+/*
+ * Export hidden columns for entities in the current clause.
+ *
+ * For each named vertex/edge entity, we export its id (and for edges:
+ * start_id, end_id) as target entries. These can be referenced by
+ * subsequent clauses without rebuilding the full vertex/edge.
+ *
+ * This function handles two cases:
+ * 1. Entities declared in the current clause: Extract id from _agtype_build_*
args
+ * 2. Entities from previous clauses (with id_var set): Re-export using their
Vars
+ *
+ * The column names use the AGE_VARNAME prefix pattern
(AGE_DEFAULT_VARNAME_PREFIX)
+ * which makes them hidden from SELECT * output. The expand_star() function in
+ * cypher_item.c filters out columns with this prefix.
+ *
+ * Note: We use resjunk=false so these columns are included in the subquery RTE
+ * when PostgreSQL builds the column list via addRangeTableEntryForSubquery().
+ * If resjunk=true, PostgreSQL would skip them entirely.
+ */
+static void export_entity_hidden_columns(cypher_parsestate *cpstate,
+ Query *query)
+{
+ ListCell *lc;
+ int resno;
+ Oid graphid_to_agtype_oid;
+ List *exported_names = NIL; /* Track entity names already exported */
+
+ /* Get the graphid_to_agtype function OID for id conversions */
+ graphid_to_agtype_oid = get_ag_func_oid("graphid_to_agtype", 1,
GRAPHIDOID);
+
+ /* find the next resno for target entries */
+ resno = list_length(query->targetList) + 1;
+
+ foreach (lc, cpstate->entities)
+ {
+ transform_entity *entity = lfirst(lc);
+ char *entity_name;
+ char *col_name;
+ TargetEntry *te;
+ ListCell *lc2;
+ bool already_exported;
+
+ /* skip entities without names - they aren't referenced */
+ entity_name = get_entity_name(entity);
+ if (entity_name == NULL)
+ {
+ continue;
+ }
+
+ /*
+ * Skip if we've already exported columns for an entity with this name.
+ * This can happen when the same variable appears multiple times in a
+ * pattern, e.g., MATCH (a)-[]->(), ()-[]->(a)
+ */
+ already_exported = false;
+ foreach (lc2, exported_names)
+ {
+ if (strcmp((char *)lfirst(lc2), entity_name) == 0)
+ {
+ already_exported = true;
+ break;
+ }
+ }
+ if (already_exported)
+ {
+ continue;
+ }
+ exported_names = lappend(exported_names, entity_name);
+
+ /* skip path entities - they don't have id/start_id/end_id */
+ if (entity->type == ENT_PATH)
+ {
+ continue;
+ }
+
+ /* skip VLE edges for now - they have different structure */
+ if (entity->type == ENT_VLE_EDGE)
+ {
+ continue;
+ }
+
+ /*
+ * Only export hidden columns for entities declared in the current
clause.
+ * Entities from previous clauses already have their
id_var/start_id_var/end_id_var
+ * pointing to the subquery's hidden columns from when they were
exported.
+ */
+ if (!entity->declared_in_current_clause)
+ {
+ continue;
+ }
+
+ /* Extract id from the entity's FuncExpr */
+ {
+ Expr *expr = entity->expr;
+ FuncExpr *func_expr;
+ Node *id_node;
+ Node *start_id_node;
+ Node *end_id_node;
+ FuncExpr *id_agtype_expr;
+ FuncExpr *start_id_agtype_expr;
+ FuncExpr *end_id_agtype_expr;
+
+ if (expr == NULL)
+ {
+ continue;
+ }
+
+ /*
+ * The expr must be a FuncExpr (_agtype_build_vertex or
_agtype_build_edge)
+ * for entities declared in the current clause.
+ */
+ if (!IsA(expr, FuncExpr))
+ {
+ continue;
+ }
+
+ func_expr = (FuncExpr *)expr;
+
+ /*
+ * For vertices: _agtype_build_vertex(id, label_name, properties)
+ * For edges: _agtype_build_edge(id, start_id, end_id, label_name,
properties)
+ */
+ if (entity->type == ENT_VERTEX)
+ {
+ /* vertex: args are (id, label_name, properties) */
+ if (list_length(func_expr->args) < 3)
+ {
+ continue;
+ }
+ id_node = (Node *)linitial(func_expr->args);
+ start_id_node = NULL;
+ end_id_node = NULL;
+ }
+ else if (entity->type == ENT_EDGE)
+ {
+ /* edge: args are (id, start_id, end_id, label_name,
properties) */
+ if (list_length(func_expr->args) < 5)
+ {
+ continue;
+ }
+ id_node = (Node *)linitial(func_expr->args);
+ start_id_node = (Node *)lsecond(func_expr->args);
+ end_id_node = (Node *)lthird(func_expr->args);
+ }
+ else
+ {
+ continue;
+ }
+
+ /*
+ * Create target entries for id (as agtype).
+ * We wrap id in graphid_to_agtype() since age_id() returns agtype.
+ */
+ id_agtype_expr = makeFuncExpr(graphid_to_agtype_oid, AGTYPEOID,
+ list_make1(copyObject(id_node)),
InvalidOid,
+ InvalidOid, COERCE_EXPLICIT_CALL);
+
+ col_name = psprintf("%s%s", AGE_VARNAME_ID_PREFIX, entity_name);
+ te = makeTargetEntry((Expr *)id_agtype_expr, resno++, col_name,
false);
+ query->targetList = lappend(query->targetList, te);
+
+ /* For edges, also export start_id and end_id */
+ if (entity->type == ENT_EDGE)
+ {
+ start_id_agtype_expr = makeFuncExpr(graphid_to_agtype_oid,
AGTYPEOID,
+
list_make1(copyObject(start_id_node)),
+ InvalidOid, InvalidOid,
+ COERCE_EXPLICIT_CALL);
+ col_name = psprintf("%s%s", AGE_VARNAME_START_ID_PREFIX,
entity_name);
+ te = makeTargetEntry((Expr *)start_id_agtype_expr, resno++,
col_name, false);
+ query->targetList = lappend(query->targetList, te);
+
+ end_id_agtype_expr = makeFuncExpr(graphid_to_agtype_oid,
AGTYPEOID,
+
list_make1(copyObject(end_id_node)),
+ InvalidOid, InvalidOid,
+ COERCE_EXPLICIT_CALL);
+ col_name = psprintf("%s%s", AGE_VARNAME_END_ID_PREFIX,
entity_name);
+ te = makeTargetEntry((Expr *)end_id_agtype_expr, resno++,
col_name, false);
+ query->targetList = lappend(query->targetList, te);
Review Comment:
Per AI, but I also know this -
No, this is not a memory leak concern in PostgreSQL's memory context system.
In PostgreSQL, memory is allocated in memory contexts (palloc/psprintf use
the current memory context). These contexts are freed in bulk at appropriate
times (end of transaction, end of query, etc.).
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
