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Fix handling of node numbers in queries with multiple alternatives #338

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4 changes: 4 additions & 0 deletions CHANGELOG.md
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0

## [Unreleased]

### Fixed

- Fixed handling of node numbers in queries with multiple alternatives.

## [4.1.4] - 2026-04-18

### Fixed
Expand Down
80 changes: 41 additions & 39 deletions graphannis/src/annis/db/aql/conjunction.rs
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Expand Up @@ -112,35 +112,6 @@ fn update_components_for_nodes(
}
}

fn get_cost_estimates<'a>(
op_spec: &BinaryOperatorSpecEntry,
node2cost: &'a BTreeMap<usize, CostEstimate>,
) -> Option<(&'a CostEstimate, &'a CostEstimate)> {
if let (Some(cost_lhs), Some(cost_rhs)) = (
node2cost.get(&op_spec.args.left),
node2cost.get(&op_spec.args.right),
) {
Some((cost_lhs, cost_rhs))
} else {
None
}
}

/// Returns true if it is estimated to switch the operands in a join.
fn should_switch_operand_order(
op_spec: &BinaryOperatorSpecEntry,
node2cost: &BTreeMap<usize, CostEstimate>,
) -> bool {
if let Some((cost_lhs, cost_rhs)) = get_cost_estimates(op_spec, node2cost)
&& cost_rhs.output < cost_lhs.output
{
// switch operands
return true;
}

false
}

fn create_index_join<'b>(
db: &'b AnnotationGraph,
config: &Config,
Expand Down Expand Up @@ -187,7 +158,7 @@ fn create_join<'b>(
if exec_right.as_nodesearch().is_some()
&& let BinaryOperator::Index(op) = op_entry.op
{
// we can use directly use an index join
// we can directly use an index join
return create_index_join(
db,
config,
Expand All @@ -200,7 +171,7 @@ fn create_join<'b>(
}

if exec_left.as_nodesearch().is_some() {
// avoid a nested loop join by switching the operand and using and index join when possible
// avoid a nested loop join by switching the operand and using an index join when possible
if let Some(BinaryOperator::Index(inverse_op)) = op_entry.op.get_inverse_operator(db)? {
let inverse_args = BinaryOperatorArguments {
left: op_entry.args.right,
Expand Down Expand Up @@ -395,7 +366,7 @@ impl Conjunction {
}

/// Return the variable name for a node number. The node number is the
/// position of an node description in the query. In case of a query with
/// position of a node description in the query. In case of a query with
/// multiple alternatives, this refers to the node number of the whole query and
/// not only the conjunction.
pub fn get_variable_by_node_nr(&self, node_nr: usize) -> Option<String> {
Expand Down Expand Up @@ -493,7 +464,7 @@ impl Conjunction {
family_operators.push(best_operator_order.clone());

for i in 0..num_new_generations {
// use the the previous generation as basis
// use the previous generation as basis
let mut tmp_operators = family_operators[i].clone();
// randomly select two joins
let mut a = 0;
Expand Down Expand Up @@ -561,7 +532,7 @@ impl Conjunction {
if let Some(node_search_cost) = desc.cost.as_ref() {
for e in op_spec_entries {
let op_spec = &e.op;
if e.args.left == desc.component_nr {
if e.args.left - self.var_idx_offset == desc.component_nr {
// get the necessary components and count the number of nodes in these components
let components = op_spec.necessary_components(db);
if !components.is_empty() {
Expand Down Expand Up @@ -686,6 +657,37 @@ impl Conjunction {
Ok(())
}

fn get_cost_estimates<'a>(
&self,
op_spec: &BinaryOperatorSpecEntry,
node2cost: &'a BTreeMap<usize, CostEstimate>,
) -> Option<(&'a CostEstimate, &'a CostEstimate)> {
if let (Some(cost_lhs), Some(cost_rhs)) = (
node2cost.get(&(op_spec.args.left - self.var_idx_offset)),
node2cost.get(&(op_spec.args.right - self.var_idx_offset)),
) {
Some((cost_lhs, cost_rhs))
} else {
None
}
}

/// Returns true if it is estimated to switch the operands in a join.
fn should_switch_operand_order(
&self,
op_spec: &BinaryOperatorSpecEntry,
node2cost: &BTreeMap<usize, CostEstimate>,
) -> bool {
if let Some((cost_lhs, cost_rhs)) = self.get_cost_estimates(op_spec, node2cost)
&& cost_rhs.output < cost_lhs.output
{
// switch operands
return true;
}

false
}

fn add_binary_operator_to_exec_plan<'a>(
&'a self,
op_spec_entry: &BinaryOperatorSpecEntry,
Expand All @@ -699,22 +701,22 @@ impl Conjunction {
) -> Result<()> {
let mut op: BinaryOperator<'a> = op_spec_entry
.op
.create_operator(g, get_cost_estimates(op_spec_entry, &helper.node2cost))?;
.create_operator(g, self.get_cost_estimates(op_spec_entry, &helper.node2cost))?;

let mut spec_idx_left = op_spec_entry.args.left;
let mut spec_idx_right = op_spec_entry.args.right;

let inverse_op = op.get_inverse_operator(g)?;
if let Some(inverse_op) = inverse_op
&& should_switch_operand_order(op_spec_entry, &helper.node2cost)
&& self.should_switch_operand_order(op_spec_entry, &helper.node2cost)
{
spec_idx_left = op_spec_entry.args.right;
spec_idx_right = op_spec_entry.args.left;

op = inverse_op;
}

// substract the offset from the specificated numbers to get the internal node number for this conjunction
// subtract the offset from the specified numbers to get the internal node number for this conjunction
spec_idx_left -= self.var_idx_offset;
spec_idx_right -= self.var_idx_offset;

Expand Down Expand Up @@ -850,7 +852,7 @@ impl Conjunction {
)?;
}

// apply the the node error check
// apply the node error check
if !output.node_search_errors.is_empty() {
return Err(output.node_search_errors.remove(0));
}
Expand Down Expand Up @@ -910,7 +912,7 @@ impl Conjunction {
&& first != *cid
{
// add location and description which node is not connected
let n_var = &self.nodes[*node_nr].var;
let n_var = &self.nodes[*node_nr - self.var_idx_offset].var;
let location = self.location_in_query.get(n_var);

return Err(GraphAnnisError::AQLSemanticError(AQLError {
Expand Down
19 changes: 19 additions & 0 deletions graphannis/src/annis/db/aql/conjunction/tests.rs
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Expand Up @@ -156,6 +156,25 @@ fn semantic_error_unbound() {
}
}

#[test]
fn semantic_error_unbound_in_non_first_alternative() {
let config = Config::default();
let g = AnnotationGraph::with_default_graphstorages(false).unwrap();
// Same as above, but the unbound variable is in a non-first alternative,
// whose nodes have a non-zero global offset. This asserts that the global
// node numbers are correctly translated to local indices.
let q = aql::parse("tok . tok | tok & tok", false).unwrap();
let plan = ExecutionPlan::from_disjunction(&q, &g, &config, TimeoutCheck::new(None));
match plan {
Err(AQLSemanticError(err)) => assert_eq!(
"Variable \"#4\" not bound (use linguistic operators)",
err.desc
),
Err(err) => panic!("Query must return a semantic error, but returned {}", err),
Ok(_) => panic!("Query must return an error"),
}
}

#[test]
fn semantic_error_optional_non_negated() {
match aql::parse("tok? & tok? & #1 . #2", false) {
Expand Down
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