Add aggregation bucket limit

CHANGELOG.md

@@ -11,6 +11,7 @@ Unreleased
 - Add [histogram](https://github.com/quickwit-oss/tantivy/pull/1306) aggregation (@PSeitz)
 - Add support for fastfield on text fields (@PSeitz)
 - Add terms aggregation (@PSeitz)
+- API Change: `SegmentCollector.collect` changed to return a `Result`. 
 
 Tantivy 0.17
 ================================

examples/aggregation.rs

@@ -117,7 +117,7 @@ fn main() -> tantivy::Result<()> {
     .into_iter()
     .collect();
 
-    let collector = AggregationCollector::from_aggs(agg_req_1);
+    let collector = AggregationCollector::from_aggs(agg_req_1, None);
 
     let searcher = reader.searcher();
     let agg_res: AggregationResults = searcher.search(&term_query, &collector).unwrap();

src/aggregation/agg_req_with_accessor.rs

@@ -1,10 +1,13 @@
 //! This will enhance the request tree with access to the fastfield and metadata.
 
+use std::rc::Rc;
+use std::sync::atomic::AtomicU32;
 use std::sync::Arc;
 
 use super::agg_req::{Aggregation, Aggregations, BucketAggregationType, MetricAggregation};
 use super::bucket::{HistogramAggregation, RangeAggregation, TermsAggregation};
 use super::metric::{AverageAggregation, StatsAggregation};
+use super::segment_agg_result::BucketCount;
 use super::VecWithNames;
 use crate::fastfield::{
     type_and_cardinality, DynamicFastFieldReader, FastType, MultiValuedFastFieldReader,
@@ -60,13 +63,16 @@ pub struct BucketAggregationWithAccessor {
     pub(crate) field_type: Type,
     pub(crate) bucket_agg: BucketAggregationType,
     pub(crate) sub_aggregation: AggregationsWithAccessor,
+    pub(crate) bucket_count: BucketCount,
 }
 
 impl BucketAggregationWithAccessor {
     fn try_from_bucket(
         bucket: &BucketAggregationType,
         sub_aggregation: &Aggregations,
         reader: &SegmentReader,
+        bucket_count: Rc<AtomicU32>,
+        max_bucket_count: u32,
     ) -> crate::Result<BucketAggregationWithAccessor> {
         let mut inverted_index = None;
         let (accessor, field_type) = match &bucket {
@@ -92,9 +98,18 @@ impl BucketAggregationWithAccessor {
         Ok(BucketAggregationWithAccessor {
             accessor,
             field_type,
-            sub_aggregation: get_aggs_with_accessor_and_validate(&sub_aggregation, reader)?,
+            sub_aggregation: get_aggs_with_accessor_and_validate(
+                &sub_aggregation,
+                reader,
+                bucket_count.clone(),
+                max_bucket_count,
+            )?,
             bucket_agg: bucket.clone(),
             inverted_index,
+            bucket_count: BucketCount {
+                bucket_count,
+                max_bucket_count,
+            },
         })
     }
 }
@@ -134,6 +149,8 @@ impl MetricAggregationWithAccessor {
 pub(crate) fn get_aggs_with_accessor_and_validate(
     aggs: &Aggregations,
     reader: &SegmentReader,
+    bucket_count: Rc<AtomicU32>,
+    max_bucket_count: u32,
 ) -> crate::Result<AggregationsWithAccessor> {
     let mut metrics = vec![];
     let mut buckets = vec![];
@@ -145,6 +162,8 @@ pub(crate) fn get_aggs_with_accessor_and_validate(
                     &bucket.bucket_agg,
                     &bucket.sub_aggregation,
                     reader,
+                    Rc::clone(&bucket_count),
+                    max_bucket_count,
                 )?,
             )),
             Aggregation::Metric(metric) => metrics.push((

src/aggregation/agg_result.rs

@@ -4,21 +4,15 @@
 //! intermediate average results, which is the sum and the number of values. The actual average is
 //! calculated on the step from intermediate to final aggregation result tree.
 
-use std::cmp::Ordering;
 use std::collections::HashMap;
 
 use serde::{Deserialize, Serialize};
 
-use super::agg_req::{
-    Aggregations, AggregationsInternal, BucketAggregationInternal, MetricAggregation,
-};
-use super::bucket::{intermediate_buckets_to_final_buckets, GetDocCount};
-use super::intermediate_agg_result::{
-    IntermediateAggregationResults, IntermediateBucketResult, IntermediateHistogramBucketEntry,
-    IntermediateMetricResult, IntermediateRangeBucketEntry,
-};
+use super::agg_req::BucketAggregationInternal;
+use super::bucket::GetDocCount;
+use super::intermediate_agg_result::{IntermediateBucketResult, IntermediateMetricResult};
 use super::metric::{SingleMetricResult, Stats};
-use super::{Key, VecWithNames};
+use super::Key;
 use crate::TantivyError;
 
 #[derive(Clone, Default, Debug, PartialEq, Serialize, Deserialize)]
@@ -41,98 +35,6 @@ impl AggregationResults {
             )))
         }
     }
-
-    /// Convert and intermediate result and its aggregation request to the final result
-    pub fn from_intermediate_and_req(
-        results: IntermediateAggregationResults,
-        agg: Aggregations,
-    ) -> crate::Result<Self> {
-        AggregationResults::from_intermediate_and_req_internal(results, &(agg.into()))
-    }
-
-    /// Convert and intermediate result and its aggregation request to the final result
-    ///
-    /// Internal function, CollectorAggregations is used instead Aggregations, which is optimized
-    /// for internal processing, by splitting metric and buckets into seperate groups.
-    pub(crate) fn from_intermediate_and_req_internal(
-        intermediate_results: IntermediateAggregationResults,
-        req: &AggregationsInternal,
-    ) -> crate::Result<Self> {
-        // Important assumption:
-        // When the tree contains buckets/metric, we expect it to have all buckets/metrics from the
-        // request
-        let mut results: HashMap<String, AggregationResult> = HashMap::new();
-
-        if let Some(buckets) = intermediate_results.buckets {
-            add_coverted_final_buckets_to_result(&mut results, buckets, &req.buckets)?
-        } else {
-            // When there are no buckets, we create empty buckets, so that the serialized json
-            // format is constant
-            add_empty_final_buckets_to_result(&mut results, &req.buckets)?
-        };
-
-        if let Some(metrics) = intermediate_results.metrics {
-            add_converted_final_metrics_to_result(&mut results, metrics);
-        } else {
-            // When there are no metrics, we create empty metric results, so that the serialized
-            // json format is constant
-            add_empty_final_metrics_to_result(&mut results, &req.metrics)?;
-        }
-        Ok(Self(results))
-    }
-}
-
-fn add_converted_final_metrics_to_result(
-    results: &mut HashMap<String, AggregationResult>,
-    metrics: VecWithNames<IntermediateMetricResult>,
-) {
-    results.extend(
-        metrics
-            .into_iter()
-            .map(|(key, metric)| (key, AggregationResult::MetricResult(metric.into()))),
-    );
-}
-
-fn add_empty_final_metrics_to_result(
-    results: &mut HashMap<String, AggregationResult>,
-    req_metrics: &VecWithNames<MetricAggregation>,
-) -> crate::Result<()> {
-    results.extend(req_metrics.iter().map(|(key, req)| {
-        let empty_bucket = IntermediateMetricResult::empty_from_req(req);
-        (
-            key.to_string(),
-            AggregationResult::MetricResult(empty_bucket.into()),
-        )
-    }));
-    Ok(())
-}
-
-fn add_empty_final_buckets_to_result(
-    results: &mut HashMap<String, AggregationResult>,
-    req_buckets: &VecWithNames<BucketAggregationInternal>,
-) -> crate::Result<()> {
-    let requested_buckets = req_buckets.iter();
-    for (key, req) in requested_buckets {
-        let empty_bucket = AggregationResult::BucketResult(BucketResult::empty_from_req(req)?);
-        results.insert(key.to_string(), empty_bucket);
-    }
-    Ok(())
-}
-
-fn add_coverted_final_buckets_to_result(
-    results: &mut HashMap<String, AggregationResult>,
-    buckets: VecWithNames<IntermediateBucketResult>,
-    req_buckets: &VecWithNames<BucketAggregationInternal>,
-) -> crate::Result<()> {
-    assert_eq!(buckets.len(), req_buckets.len());
-
-    let buckets_with_request = buckets.into_iter().zip(req_buckets.values());
-    for ((key, bucket), req) in buckets_with_request {
-        let result =
-            AggregationResult::BucketResult(BucketResult::from_intermediate_and_req(bucket, req)?);
-        results.insert(key, result);
-    }
-    Ok(())
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
@@ -154,7 +56,8 @@ impl AggregationResult {
         match self {
             AggregationResult::BucketResult(_bucket) => Err(TantivyError::InternalError(
                 "Tried to retrieve value from bucket aggregation. This is not supported and \
-                 should not happen during collection, but should be catched during validation"
+                 should not happen during collection phase, but should be catched during \
+                 validation"
                     .to_string(),
             )),
             AggregationResult::MetricResult(metric) => metric.get_value(agg_property),
@@ -230,48 +133,7 @@ pub enum BucketResult {
 impl BucketResult {
     pub(crate) fn empty_from_req(req: &BucketAggregationInternal) -> crate::Result<Self> {
         let empty_bucket = IntermediateBucketResult::empty_from_req(&req.bucket_agg);
-        BucketResult::from_intermediate_and_req(empty_bucket, req)
-    }
-
-    fn from_intermediate_and_req(
-        bucket_result: IntermediateBucketResult,
-        req: &BucketAggregationInternal,
-    ) -> crate::Result<Self> {
-        match bucket_result {
-            IntermediateBucketResult::Range(range_res) => {
-                let mut buckets: Vec<RangeBucketEntry> = range_res
-                    .buckets
-                    .into_iter()
-                    .map(|(_, bucket)| {
-                        RangeBucketEntry::from_intermediate_and_req(bucket, &req.sub_aggregation)
-                    })
-                    .collect::<crate::Result<Vec<_>>>()?;
-
-                buckets.sort_by(|left, right| {
-                    // TODO use total_cmp next stable rust release
-                    left.from
-                        .unwrap_or(f64::MIN)
-                        .partial_cmp(&right.from.unwrap_or(f64::MIN))
-                        .unwrap_or(Ordering::Equal)
-                });
-                Ok(BucketResult::Range { buckets })
-            }
-            IntermediateBucketResult::Histogram { buckets } => {
-                let buckets = intermediate_buckets_to_final_buckets(
-                    buckets,
-                    req.as_histogram()
-                        .expect("unexpected aggregation, expected histogram aggregation"),
-                    &req.sub_aggregation,
-                )?;
-
-                Ok(BucketResult::Histogram { buckets })
-            }
-            IntermediateBucketResult::Terms(terms) => terms.into_final_result(
-                req.as_term()
-                    .expect("unexpected aggregation, expected term aggregation"),
-                &req.sub_aggregation,
-            ),
-        }
+        empty_bucket.into_final_bucket_result(req)
     }
 }
 
@@ -311,22 +173,6 @@ pub struct BucketEntry {
     /// Sub-aggregations in this bucket.
     pub sub_aggregation: AggregationResults,
 }
-
-impl BucketEntry {
-    pub(crate) fn from_intermediate_and_req(
-        entry: IntermediateHistogramBucketEntry,
-        req: &AggregationsInternal,
-    ) -> crate::Result<Self> {
-        Ok(BucketEntry {
-            key: Key::F64(entry.key),
-            doc_count: entry.doc_count,
-            sub_aggregation: AggregationResults::from_intermediate_and_req_internal(
-                entry.sub_aggregation,
-                req,
-            )?,
-        })
-    }
-}
 impl GetDocCount for &BucketEntry {
     fn doc_count(&self) -> u64 {
         self.doc_count
@@ -384,21 +230,3 @@ pub struct RangeBucketEntry {
     #[serde(skip_serializing_if = "Option::is_none")]
     pub to: Option<f64>,
 }
-
-impl RangeBucketEntry {
-    fn from_intermediate_and_req(
-        entry: IntermediateRangeBucketEntry,
-        req: &AggregationsInternal,
-    ) -> crate::Result<Self> {
-        Ok(RangeBucketEntry {
-            key: entry.key,
-            doc_count: entry.doc_count,
-            sub_aggregation: AggregationResults::from_intermediate_and_req_internal(
-                entry.sub_aggregation,
-                req,
-            )?,
-            to: entry.to,
-            from: entry.from,
-        })
-    }
-}