afs commented on code in PR #2925:
URL: https://github.com/apache/jena/pull/2925#discussion_r1916747478
##########
jena-arq/src/main/java/org/apache/jena/sparql/engine/iterator/QueryIterLateral.java:
##########
@@ -292,17 +295,33 @@ public Op transform(OpTable opTable) {
// By the assignment restriction, the binding only needs to be
added to each row of the table.
Table table = opTable.getTable();
// Table vars.
- List<Var> vars = new ArrayList<>(table.getVars());
- binding.vars().forEachRemaining(vars::add);
- TableN table2 = new TableN(vars);
+ List<Var> tableVars = table.getVars();
+ List<Var> vars = new ArrayList<>(tableVars);
+
+ // Track variables that appear both in the table and the binding.
+ List<Var> commonVars = new ArrayList<>();
+
+ // Index variables in a set if there are more than a few of them.
+ Collection<Var> tableVarsIndex = tableVars.size() > 4 ? new
HashSet<>(tableVars) : tableVars;
+ binding.vars().forEachRemaining(v -> {
+ if (tableVarsIndex.contains(v)) {
Review Comment:
The table vars can't contain a binding var. That case is caught by the
https://github.com/w3c/sparql-dev/blob/main/SEP/SEP-0007/sep-0007.md
"Disallow syntactic forms that set variables that may already be present in
the current row."
It's tested in `SyntaxVarScope.checkLATEAL`.
(I removed the `if`, left the `else` and the second test passes).
If so, it simplifies to `vars.add(v);`
And hence "vars = tableVars" (copy not needed).
##########
jena-arq/src/main/java/org/apache/jena/sparql/engine/iterator/QueryIterLateral.java:
##########
@@ -292,17 +295,33 @@ public Op transform(OpTable opTable) {
// By the assignment restriction, the binding only needs to be
added to each row of the table.
Table table = opTable.getTable();
// Table vars.
- List<Var> vars = new ArrayList<>(table.getVars());
- binding.vars().forEachRemaining(vars::add);
- TableN table2 = new TableN(vars);
+ List<Var> tableVars = table.getVars();
+ List<Var> vars = new ArrayList<>(tableVars);
+
+ // Track variables that appear both in the table and the binding.
+ List<Var> commonVars = new ArrayList<>();
+
+ // Index variables in a set if there are more than a few of them.
+ Collection<Var> tableVarsIndex = tableVars.size() > 4 ? new
HashSet<>(tableVars) : tableVars;
+ binding.vars().forEachRemaining(v -> {
+ if (tableVarsIndex.contains(v)) {
+ commonVars.add(v);
+ } else {
+ vars.add(v);
+ }
+ });
+
+ List<Binding> bindings = new ArrayList<>(table.size());
BindingBuilder builder = BindingFactory.builder();
table.iterator(null).forEachRemaining(row->{
- builder.reset();
- builder.addAll(row);
- builder.addAll(binding);
- table2.addBinding(builder.build());
+ if (Algebra.compatible(row, binding, commonVars.iterator())) {
Review Comment:
If there is a variable in common from substitution it must be the same term.
So this is a contains relationship. (Given the comments above there may be a
simpler way.)
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