OpenSearch/docs/reference/aggregations/pipeline/cumulative-sum-aggregation.asciidoc
Zachary Tong 6ae6f57d39
[7.x Backport] Force selection of calendar or fixed intervals (#41906)
The date_histogram accepts an interval which can be either a calendar
interval (DST-aware, leap seconds, arbitrary length of months, etc) or
fixed interval (strict multiples of SI units). Unfortunately this is inferred
by first trying to parse as a calendar interval, then falling back to fixed
if that fails.

This leads to confusing arrangement where `1d` == calendar, but
`2d` == fixed.  And if you want a day of fixed time, you have to
specify `24h` (e.g. the next smallest unit).  This arrangement is very
error-prone for users.

This PR adds `calendar_interval` and `fixed_interval` parameters to any
code that uses intervals (date_histogram, rollup, composite, datafeed, etc).
Calendar only accepts calendar intervals, fixed accepts any combination of
units (meaning `1d` can be used to specify `24h` in fixed time), and both
are mutually exclusive.

The old interval behavior is deprecated and will throw a deprecation warning.
It is also mutually exclusive with the two new parameters. In the future the
old dual-purpose interval will be removed.

The change applies to both REST and java clients.
2019-05-20 12:07:29 -04:00

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[[search-aggregations-pipeline-cumulative-sum-aggregation]]
=== Cumulative Sum Aggregation
A parent pipeline aggregation which calculates the cumulative sum of a specified metric in a parent histogram (or date_histogram)
aggregation. The specified metric must be numeric and the enclosing histogram must have `min_doc_count` set to `0` (default
for `histogram` aggregations).
==== Syntax
A `cumulative_sum` aggregation looks like this in isolation:
[source,js]
--------------------------------------------------
{
"cumulative_sum": {
"buckets_path": "the_sum"
}
}
--------------------------------------------------
// NOTCONSOLE
[[cumulative-sum-params]]
.`cumulative_sum` Parameters
[options="header"]
|===
|Parameter Name |Description |Required |Default Value
|`buckets_path` |The path to the buckets we wish to find the cumulative sum for (see <<buckets-path-syntax>> for more
details) |Required |
|`format` |format to apply to the output value of this aggregation |Optional |`null`
|===
The following snippet calculates the cumulative sum of the total monthly `sales`:
[source,js]
--------------------------------------------------
POST /sales/_search
{
"size": 0,
"aggs" : {
"sales_per_month" : {
"date_histogram" : {
"field" : "date",
"calendar_interval" : "month"
},
"aggs": {
"sales": {
"sum": {
"field": "price"
}
},
"cumulative_sales": {
"cumulative_sum": {
"buckets_path": "sales" <1>
}
}
}
}
}
}
--------------------------------------------------
// CONSOLE
// TEST[setup:sales]
<1> `buckets_path` instructs this cumulative sum aggregation to use the output of the `sales` aggregation for the cumulative sum
And the following may be the response:
[source,js]
--------------------------------------------------
{
"took": 11,
"timed_out": false,
"_shards": ...,
"hits": ...,
"aggregations": {
"sales_per_month": {
"buckets": [
{
"key_as_string": "2015/01/01 00:00:00",
"key": 1420070400000,
"doc_count": 3,
"sales": {
"value": 550.0
},
"cumulative_sales": {
"value": 550.0
}
},
{
"key_as_string": "2015/02/01 00:00:00",
"key": 1422748800000,
"doc_count": 2,
"sales": {
"value": 60.0
},
"cumulative_sales": {
"value": 610.0
}
},
{
"key_as_string": "2015/03/01 00:00:00",
"key": 1425168000000,
"doc_count": 2,
"sales": {
"value": 375.0
},
"cumulative_sales": {
"value": 985.0
}
}
]
}
}
}
--------------------------------------------------
// TESTRESPONSE[s/"took": 11/"took": $body.took/]
// TESTRESPONSE[s/"_shards": \.\.\./"_shards": $body._shards/]
// TESTRESPONSE[s/"hits": \.\.\./"hits": $body.hits/]