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« Significant Terms Aggregation Usage Pipeline Aggregations »
Elastic Docs ›Elasticsearch.Net and NEST: the .NET clients [5.x] ›Aggregations ›Bucket Aggregations

Terms Aggregation Usage

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Terms Aggregation Usage

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A multi-bucket value source based aggregation where buckets are dynamically built - one per unique value.

See the Elasticsearch documentation on terms aggregation for more detail.

Fluent DSL example

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s => s
.Size(0)
.Aggregations(a => a
    .Terms("states", st => st
        .Field(p => p.State)
        .MinimumDocumentCount(2)
        .Size(5)
        .ShardSize(100)
        .ExecutionHint(TermsAggregationExecutionHint.Map)
        .Missing("n/a")
        .Script(ss => ss.Inline("'State of Being: '+_value").Lang("groovy"))
        .Order(TermsOrder.TermAscending)
        .Order(TermsOrder.CountDescending)
        .Meta(m => m
            .Add("foo", "bar")
        )
    )
)

Object Initializer syntax example

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new SearchRequest<Project>
{
    Size = 0,
    Aggregations = new TermsAggregation("states")
    {
        Field = Field<Project>(p => p.State),
        MinimumDocumentCount = 2,
        Size = 5,
        ShardSize = 100,
        ExecutionHint = TermsAggregationExecutionHint.Map,
        Missing = "n/a",
        Script = new InlineScript("'State of Being: '+_value") { Lang = "groovy" },
        Order = new List<TermsOrder>
        {
            TermsOrder.TermAscending,
            TermsOrder.CountDescending
        },
        Meta = new Dictionary<string, object>
        {
            { "foo", "bar" }
        }
    }
}

Example json output.

{
  "size": 0,
  "aggs": {
    "states": {
      "meta": {
        "foo": "bar"
      },
      "terms": {
        "field": "state",
        "min_doc_count": 2,
        "size": 5,
        "shard_size": 100,
        "execution_hint": "map",
        "missing": "n/a",
        "script": {
          "inline": "'State of Being: '+_value",
          "lang": "groovy"
        },
        "order": [
          {
            "_term": "asc"
          },
          {
            "_count": "desc"
          }
        ]
      }
    }
  }
}

Handling Responses

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response.ShouldBeValid();
var states = response.Aggs.Terms("states");
states.Should().NotBeNull();
states.DocCountErrorUpperBound.Should().HaveValue();
states.SumOtherDocCount.Should().HaveValue();
states.Buckets.Should().NotBeNull();
states.Buckets.Count.Should().BeGreaterThan(0);
foreach (var item in states.Buckets)
{
    item.Key.Should().NotBeNullOrEmpty();
    item.DocCount.Should().BeGreaterOrEqualTo(1);
}
states.Meta.Should().NotBeNull().And.HaveCount(1);
states.Meta["foo"].Should().Be("bar");

Filtering with a regular expression pattern

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Using terms aggregation with filtering to include values using a regular expression pattern

Fluent DSL example

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s => s
.Size(0)
.Aggregations(a => a
    .Terms("states", st => st
        .Field(p => p.State.Suffix("keyword"))
        .MinimumDocumentCount(2)
        .Size(5)
        .ShardSize(100)
        .ExecutionHint(TermsAggregationExecutionHint.Map)
        .Missing("n/a")
        .Include("(Stable|VeryActive)")
        .Order(TermsOrder.TermAscending)
        .Order(TermsOrder.CountDescending)
        .Meta(m => m
            .Add("foo", "bar")
        )
    )
)

Object Initializer syntax example

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new SearchRequest<Project>
{
    Size = 0,
    Aggregations = new TermsAggregation("states")
    {
        Field = Field<Project>(p => p.State.Suffix("keyword")),
        MinimumDocumentCount = 2,
        Size = 5,
        ShardSize = 100,
        ExecutionHint = TermsAggregationExecutionHint.Map,
        Missing = "n/a",
        Include = new TermsIncludeExclude { Pattern = "(Stable|VeryActive)" },
        Order = new List<TermsOrder>
        {
            TermsOrder.TermAscending,
            TermsOrder.CountDescending
        },
        Meta = new Dictionary<string, object>
        {
            { "foo", "bar" }
        }
    }
}

Example json output.

{
  "size": 0,
  "aggs": {
    "states": {
      "meta": {
        "foo": "bar"
      },
      "terms": {
        "field": "state.keyword",
        "min_doc_count": 2,
        "size": 5,
        "shard_size": 100,
        "execution_hint": "map",
        "missing": "n/a",
        "include": "(Stable|VeryActive)",
        "order": [
          {
            "_term": "asc"
          },
          {
            "_count": "desc"
          }
        ]
      }
    }
  }
}

Handling Responses

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response.ShouldBeValid();
var states = response.Aggs.Terms("states");
states.Should().NotBeNull();
states.DocCountErrorUpperBound.Should().HaveValue();
states.SumOtherDocCount.Should().HaveValue();
states.Buckets.Should().NotBeNull();
states.Buckets.Count.Should().BeGreaterThan(0);
foreach (var item in states.Buckets)
{
    item.Key.Should().NotBeNullOrEmpty();
    item.DocCount.Should().BeGreaterOrEqualTo(1);
}
states.Meta.Should().NotBeNull().And.HaveCount(1);
states.Meta["foo"].Should().Be("bar");

Filtering with exact values

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Using terms aggregation with filtering to include only specific values

Fluent DSL example

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s => s
.Size(0)
.Aggregations(a => a
    .Terms("states", st => st
        .Field(p => p.State.Suffix("keyword"))
        .MinimumDocumentCount(2)
        .Size(5)
        .ShardSize(100)
        .ExecutionHint(TermsAggregationExecutionHint.Map)
        .Missing("n/a")
        .Include(new[] { StateOfBeing.Stable.ToString(), StateOfBeing.VeryActive.ToString() })
        .Order(TermsOrder.TermAscending)
        .Order(TermsOrder.CountDescending)
        .Meta(m => m
            .Add("foo", "bar")
        )
    )
)

Object Initializer syntax example

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new SearchRequest<Project>
{
    Size = 0,
    Aggregations = new TermsAggregation("states")
    {
        Field = Field<Project>(p => p.State.Suffix("keyword")),
        MinimumDocumentCount = 2,
        Size = 5,
        ShardSize = 100,
        ExecutionHint = TermsAggregationExecutionHint.Map,
        Missing = "n/a",
        Include = new TermsIncludeExclude { Values = new[] { StateOfBeing.Stable.ToString(), StateOfBeing.VeryActive.ToString() } },
        Order = new List<TermsOrder>
        {
            TermsOrder.TermAscending,
            TermsOrder.CountDescending
        },
        Meta = new Dictionary<string, object>
        {
            { "foo", "bar" }
        }
    }
}

Example json output.

{
  "size": 0,
  "aggs": {
    "states": {
      "meta": {
        "foo": "bar"
      },
      "terms": {
        "field": "state.keyword",
        "min_doc_count": 2,
        "size": 5,
        "shard_size": 100,
        "execution_hint": "map",
        "missing": "n/a",
        "include": [
          "Stable",
          "VeryActive"
        ],
        "order": [
          {
            "_term": "asc"
          },
          {
            "_count": "desc"
          }
        ]
      }
    }
  }
}

Handling Responses

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response.ShouldBeValid();
var states = response.Aggs.Terms("states");
states.Should().NotBeNull();
states.DocCountErrorUpperBound.Should().HaveValue();
states.SumOtherDocCount.Should().HaveValue();
states.Buckets.Should().NotBeNull();
states.Buckets.Count.Should().BeGreaterThan(0);
foreach (var item in states.Buckets)
{
    item.Key.Should().NotBeNullOrEmpty();
    item.DocCount.Should().BeGreaterOrEqualTo(1);
}
states.Meta.Should().NotBeNull().And.HaveCount(1);
states.Meta["foo"].Should().Be("bar");

Filtering with partitions

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A terms aggregation that uses partitioning to filter the terms that are returned in the response. Further terms can be returned by issuing additional requests with an incrementing partition number.

Partitioning is available only in Elasticsearch 5.2.0+

Fluent DSL example

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s => s
.Size(0)
.Aggregations(a => a
    .Terms("commits", st => st
        .Field(p => p.NumberOfCommits)
        .Include(0, 10)
        .Size(5)
    )
)

Object Initializer syntax example

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new SearchRequest<Project>
{
    Size = 0,
    Aggregations = new TermsAggregation("commits")
    {
        Field = Field<Project>(p => p.NumberOfCommits),
        Include = new TermsIncludeExclude
        {
            Partition = 0,
            NumberOfPartitions = 10
        },
        Size = 5
    }
}

Example json output.

{
  "size": 0,
  "aggs": {
    "commits": {
      "terms": {
        "field": "numberOfCommits",
        "size": 5,
        "include": {
          "partition": 0,
          "num_partitions": 10
        }
      }
    }
  }
}

Handling Responses

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response.ShouldBeValid();
var commits = response.Aggs.Terms<int>("commits");
commits.Should().NotBeNull();
commits.DocCountErrorUpperBound.Should().HaveValue();
commits.SumOtherDocCount.Should().HaveValue();
commits.Buckets.Should().NotBeNull();
commits.Buckets.Count.Should().BeGreaterThan(0);
foreach (var item in commits.Buckets)
{
    item.Key.Should().BeGreaterThan(0);
    item.DocCount.Should().BeGreaterOrEqualTo(1);
}

Numeric fields

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A terms aggregation on a numeric field

Fluent DSL example

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s => s
.Size(0)
.Aggregations(a => a
    .Terms("commits", st => st
        .Field(p => p.NumberOfCommits)
        .ShowTermDocCountError()
    )
)

Object Initializer syntax example

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new SearchRequest<Project>
{
    Size = 0,
    Aggregations = new TermsAggregation("commits")
    {
        Field = Field<Project>(p => p.NumberOfCommits),
        ShowTermDocCountError = true
    }
}

Example json output.

{
  "size": 0,
  "aggs": {
    "commits": {
      "terms": {
        "field": "numberOfCommits",
        "show_term_doc_count_error": true
      }
    }
  }
}

Handling Responses

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response.ShouldBeValid();
var commits = response.Aggs.Terms<int>("commits");
commits.Should().NotBeNull();
commits.DocCountErrorUpperBound.Should().HaveValue();
commits.SumOtherDocCount.Should().HaveValue();
commits.Buckets.Should().NotBeNull();
commits.Buckets.Count.Should().BeGreaterThan(0);
foreach (var item in commits.Buckets)
{
    item.Key.Should().BeGreaterThan(0);
    item.DocCount.Should().BeGreaterOrEqualTo(1);
}
commits.Buckets.Should().Contain(b => b.DocCountErrorUpperBound.HasValue);
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