Class NestedAggregator
- All Implemented Interfaces:
Closeable
,AutoCloseable
,org.apache.lucene.search.Collector
,Releasable
,SingleBucketAggregator
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Nested Class Summary
Nested classes/interfaces inherited from class org.elasticsearch.search.aggregations.bucket.BucketsAggregator
BucketsAggregator.BucketBuilderForFixedCount<B>, BucketsAggregator.BucketBuilderForVariable<B>, BucketsAggregator.ResultBuilderForVariable<B>, BucketsAggregator.SingleBucketResultBuilder
Nested classes/interfaces inherited from class org.elasticsearch.search.aggregations.Aggregator
Aggregator.BucketComparator, Aggregator.Parser, Aggregator.SubAggCollectionMode
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Field Summary
Fields inherited from class org.elasticsearch.search.aggregations.bucket.BucketsAggregator
docCountProvider
Fields inherited from class org.elasticsearch.search.aggregations.AggregatorBase
collectableSubAggregators, DEFAULT_WEIGHT, name, parent, subAggregators
Fields inherited from class org.elasticsearch.search.aggregations.BucketCollector
NO_OP_COLLECTOR
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Method Summary
Modifier and TypeMethodDescriptionbuildAggregations
(long[] owningBucketOrds) Build the results of this aggregation.Build an empty aggregation.protected void
Can be overridden by aggregator implementation to be called back when the collection phase ends.getLeafCollector
(org.apache.lucene.index.LeafReaderContext ctx, LeafBucketCollector sub) Collect results for this leaf.protected void
preGetSubLeafCollectors
(org.apache.lucene.index.LeafReaderContext ctx) Can be overridden by aggregator implementations that like the perform an operation before the leaf collectors of children aggregators are instantiated for the next segment.Methods inherited from class org.elasticsearch.search.aggregations.bucket.BucketsAggregator
bucketComparator, bucketDocCount, buildAggregationsForFixedBucketCount, buildAggregationsForSingleBucket, buildAggregationsForVariableBuckets, buildSubAggsForAllBuckets, buildSubAggsForBuckets, buildSubAggsForBuckets, close, collectBucket, collectExistingBucket, descendsFromGlobalAggregator, getDocCounts, grow, incrementBucketDocCount, maxBucketOrd, prepareSubAggs, resolveSortPath, rewriteBuckets
Methods inherited from class org.elasticsearch.search.aggregations.AggregatorBase
addRequestCircuitBreakerBytes, bigArrays, buildEmptySubAggregations, doClose, doPreCollection, getLeafCollector, metadata, name, parent, pointReaderIfAvailable, postCollection, preCollection, scoreMode, searcher, subAggregator, subAggregators, topLevelQuery, toString
Methods inherited from class org.elasticsearch.search.aggregations.Aggregator
buildTopLevel, collectDebugInfo, resolveSortPathOnValidAgg
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Method Details
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getLeafCollector
public LeafBucketCollector getLeafCollector(org.apache.lucene.index.LeafReaderContext ctx, LeafBucketCollector sub) throws IOException Description copied from class:AggregatorBase
Collect results for this leaf.Most Aggregators will return a custom
LeafBucketCollector
that collects document information for every hit. Callers of this method will make sure to callcollect
for every hit. So anyAggregator
that returns a customer LeafBucketCollector from this method runs at bestO(hits)
time. See thesum
Aggregator for a fairly strait forward example of this.Some Aggregators are able to correctly collect results on their own, without being iterated by the top level query or the rest of the aggregations framework. These aggregations collect what they need by calling methods on
LeafReaderContext
and then they returnLeafBucketCollector.NO_OP_COLLECTOR
to signal that they've done their own collection. These aggregations can do better thanO(hits)
. See themin
Aggregator for an example of an aggregation that does this. It happens to run in constant time in some cases.In other cases
MinAggregator
can't get correct results by taking the constant time path so instead it returns a customLeafBucketCollector
. This is fairly common for aggregations that have these fast paths because most of these fast paths are only possible when the aggregation is at the root of the tree.Its also useful to look at the
filters
Aggregator chooses whether or not it can use the fast path before building the Aggregator rather than on each leaf. Either is fine.- Specified by:
getLeafCollector
in classAggregatorBase
- Throws:
IOException
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preGetSubLeafCollectors
protected void preGetSubLeafCollectors(org.apache.lucene.index.LeafReaderContext ctx) throws IOException Description copied from class:AggregatorBase
Can be overridden by aggregator implementations that like the perform an operation before the leaf collectors of children aggregators are instantiated for the next segment.- Overrides:
preGetSubLeafCollectors
in classBucketsAggregator
- Throws:
IOException
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doPostCollection
Description copied from class:AggregatorBase
Can be overridden by aggregator implementation to be called back when the collection phase ends.- Overrides:
doPostCollection
in classAggregatorBase
- Throws:
IOException
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buildAggregations
Description copied from class:Aggregator
Build the results of this aggregation.- Specified by:
buildAggregations
in classAggregator
- Parameters:
owningBucketOrds
- the ordinals of the buckets that we want to collect from this aggregation- Returns:
- the results for each ordinal, in the same order as the array of ordinals
- Throws:
IOException
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buildEmptyAggregation
Description copied from class:Aggregator
Build an empty aggregation.- Specified by:
buildEmptyAggregation
in classAggregator
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