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Serial Differencing Aggregation Usageedit
Fluent DSL exampleedit
s => s
.Size(0)
.Aggregations(a => a
.DateHistogram("projects_started_per_month", dh => dh
.Field(p => p.StartedOn)
.Interval(DateInterval.Month)
.Aggregations(aa => aa
.Sum("commits", sm => sm
.Field(p => p.NumberOfCommits)
)
.SerialDifferencing("second_difference", d => d
.BucketsPath("commits")
.Lag(2)
)
)
)
)
Object Initializer syntax exampleedit
new SearchRequest<Project>
{
Size = 0,
Aggregations = new DateHistogramAggregation("projects_started_per_month")
{
Field = "startedOn",
Interval = DateInterval.Month,
Aggregations =
new SumAggregation("commits", "numberOfCommits") &&
new SerialDifferencingAggregation("second_difference", "commits")
{
Lag = 2
}
}
}
Example json output.
{
"size": 0,
"aggs": {
"projects_started_per_month": {
"date_histogram": {
"field": "startedOn",
"interval": "month"
},
"aggs": {
"commits": {
"sum": {
"field": "numberOfCommits"
}
},
"second_difference": {
"serial_diff": {
"buckets_path": "commits",
"lag": 2
}
}
}
}
}
}
Handling Responsesedit
response.ShouldBeValid();
var projectsPerMonth = response.Aggs.DateHistogram("projects_started_per_month");
projectsPerMonth.Should().NotBeNull();
projectsPerMonth.Buckets.Should().NotBeNull();
projectsPerMonth.Buckets.Count.Should().BeGreaterThan(0);
var differenceCount = 0;
foreach (var item in projectsPerMonth.Buckets)
{
differenceCount++;
var commits = item.Sum("commits");
commits.Should().NotBeNull();
commits.Value.Should().NotBe(null);
var secondDifference = item.SerialDifferencing("second_difference");
// serial differencing specified a lag of 2, so
// only expect values from the 3rd bucket onwards
if (differenceCount <= 2)
secondDifference.Should().BeNull();
else
{
secondDifference.Should().NotBeNull();
secondDifference.Value.Should().NotBe(null);
}
}