This cleans up a few rough edged in the `variable_width_histogram`,
mostly found by @wwang500:
1. Setting its tuning parameters in an unexpected order could cause the
request to fail.
2. We checked that the maximum number of buckets was both less than
50000 and MAX_BUCKETS. This drops the 50000.
3. Fixes a divide by 0 that can occur of the `shard_size` is 1.
4. Fixes a divide by 0 that can occur if the `shard_size * 3` overflows
a signed int.
5. Requires `shard_size * 3 / 4` to be at least `buckets`. If it is less
than `buckets` we will very consistently return fewer buckets than
requested. For the most part we expect folks to leave it at the
default. If they change it, we expect it to be much bigger than
`buckets`.
6. Allocate a smaller `mergeMap` in when initially bucketing requests
that don't use the entire `shard_size * 3 / 4`. Its just a waste.
7. Default `shard_size` to `10 * buckets` rather than `100`. It *looks*
like that was our intention the whole time. And it feels like it'd
keep the algorithm humming along more smoothly.
8. Default the `initial_buffer` to `min(10 * shard_size, 50000)` like
we've documented it rather than `5000`. Like the point above, this
feels like the right thing to do to keep the algorithm happy.
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
Moves the highlighting docs from the deprecated 'Request Body Search'
chapter to the new subpage of the 'Run a search chapter' section.
No substantive changes were made to the content.
This request:
```
POST /_search
{
"aggs": {
"a": {
"adjacency_matrix": {
"filters": {
"1": {
"terms": { "t": { "index": "lookup", "id": "1", "path": "t" } }
}
}
}
}
}
}
```
Would fail with a 500 error and a message like:
```
{
"error": {
"root_cause": [
{
"type": "illegal_state_exception",
"reason":"async actions are left after rewrite"
}
]
}
}
```
This fixes that by moving the query rewrite phase from a synchronous
call on the data nodes into the standard aggregation rewrite phase which
can properly handle the asynchronous actions.
Adds an explicit check to `variable_width_histogram` to stop it from
trying to collect from many buckets because it can't. I tried to make it
do so but that is more than an afternoon's project, sadly. So for now we
just disallow it.
Relates to #42035
We're tracking this aggregation's experimental-progress in #58573. We'd
like a little time to be able to make backwards incompatible changes to
the aggregation because we're not 100% sure about the request and
response format yet.
Implements a new histogram aggregation called `variable_width_histogram` which
dynamically determines bucket intervals based on document groupings. These
groups are determined by running a one-pass clustering algorithm on each shard
and then reducing each shard's clusters using an agglomerative
clustering algorithm.
This PR addresses #9572.
The shard-level clustering is done in one pass to minimize memory overhead. The
algorithm was lightly inspired by
[this paper](https://ieeexplore.ieee.org/abstract/document/1198387). It fetches
a small number of documents to sample the data and determine initial clusters.
Subsequent documents are then placed into one of these clusters, or a new one
if they are an outlier. This algorithm is described in more details in the
aggregation's docs.
At reduce time, a
[hierarchical agglomerative clustering](https://en.wikipedia.org/wiki/Hierarchical_clustering)
algorithm inspired by [this paper](https://arxiv.org/abs/1802.00304)
continually merges the closest buckets from all shards (based on their
centroids) until the target number of buckets is reached.
The final values produced by this aggregation are approximate. Each bucket's
min value is used as its key in the histogram. Furthermore, buckets are merged
based on their centroids and not their bounds. So it is possible that adjacent
buckets will overlap after reduction. Because each bucket's key is its min,
this overlap is not shown in the final histogram. However, when such overlap
occurs, we set the key of the bucket with the larger centroid to the midpoint
between its minimum and the smaller bucket’s maximum:
`min[large] = (min[large] + max[small]) / 2`. This heuristic is expected to
increases the accuracy of the clustering.
Nodes are unable to share centroids during the shard-level clustering phase. In
the future, resolving https://github.com/elastic/elasticsearch/issues/50863
would let us solve this issue.
It doesn’t make sense for this aggregation to support the `min_doc_count`
parameter, since clusters are determined dynamically. The `order` parameter is
not supported here to keep this large PR from becoming too complex.
Co-authored-by: James Dorfman <jamesdorfman@users.noreply.github.com>
Changes:
* Condenses and relocates the `docvalue_fields` example to the 'Run a search'
page.
* Adds docs for the `docvalue_fields` request body parameter.
* Updates several related xrefs.
Co-authored-by: debadair <debadair@elastic.co>
Per 49554 I added standard deviation sampling and variance sampling to the extended stats interface.
Closes#49554
Co-authored-by: Igor Motov <igor@motovs.org>
Co-authored-by: andrewjohnson2 <aj114114@gmail.com>
* Make it more clear that you can use `month` or `1M`.
* Explain rounding rules
* Consistently use "time zone" instead of "timezone". It looks like both
are right but I see "time zone" much more. And the parameter in
elasticsearch is `time_zone` so we may as well line up.
Closes#56760
Co-authored-by: James Rodewig <james.rodewig@elastic.co>
This aggregation will perform normalizations of metrics
for a given series of data in the form of bucket values.
The aggregations supports the following normalizations
- rescale 0-1
- rescale 0-100
- percentage of sum
- mean normalization
- z-score normalization
- softmax normalization
To specify which normalization is to be used, it can be specified
in the normalize agg's `normalizer` field.
For example:
```
{
"normalize": {
"buckets_path": <>,
"normalizer": "percent"
}
}
```
Similar to what the moving function aggregation does, except merging windows of percentiles
sketches together instead of cumulatively merging final metrics
Backports #55933 to 7.x
Implements value_count and avg aggregations over Histogram fields as discussed in #53285
- value_count returns the sum of all counts array of the histograms
- avg computes a weighted average of the values array of the histogram by multiplying each value with its associated element in the counts array
Removes an example from the "Document counts are approximate" section of the
terms agg documentation.
As #52377 details, the example was no longer accurate in 7.x or 6.8. Document
counts were more precise than the example presented.
We've opened issue #56025 to discuss re-adding an example later.
Co-authored-by: James Rodewig <james.rodewig@elastic.co>
Co-authored-by: AB Prashanth <panuradh@buffalo.edu>
Implements Sum aggregation over Histogram fields by summing the value of each bucket multiplied by their count as requested in #53285
Backports #55681 to 7.x
This adds a validation to VSParserHelper to ensure that a field or
script or both are specified by the user. This is technically
required today already, but throws an exception much deeper
in the agg framework and has a very unintuitive error for the user
(as well as eating more resources instead of failing early)
Adds support for filters to T-Test aggregation. The filters can be used to
select populations based on some criteria and use values from the same or
different fields.
Closes#53692
Adds t_test metric aggregation that can perform paired and unpaired two-sample
t-tests. In this PR support for filters in unpaired is still missing. It will
be added in a follow-up PR.
Relates to #53692
* Removes experimental.
* Replaces `"v"` (for value) with `"m"` (for metric).
* Move the note about tiebreaking into the list of limitations of the
sort.
* Explain how you ask for `metrics`.
* Clean up some wording.
* Link to the docs from `top_metrics`.
Closes#51813
This changes the `top_metrics` aggregation to return metrics in their
original type. Since it only supports numerics, that means that dates,
longs, and doubles will come back as stored, with their appropriate
formatter applied.
The `top_metrics` agg is kind of like `top_hits` but it only works on
doc values so it *should* be faster.
At this point it is fairly limited in that it only supports a single,
numeric sort and a single, numeric metric. And it only fetches the "very
topest" document worth of metric. We plan to support returning a
configurable number of top metrics, requesting more than one metric and
more than one sort. And, eventually, non-numeric sorts and metrics. The
trick is doing those things fairly efficiently.
Co-Authored by: Zachary Tong <zach@elastic.co>
The method parameter is not used in the percentile aggs, instead
the method is determined by the presence of `hdr` or `tdigest`
objects.
Relates to #8324
* Adds support for geo-bounds filtering in geogrid aggregations (#50002)
It is fairly common to filter the geo point candidates in
geohash_grid and geotile_grid aggregations according to some
viewable bounding box. This change introduces the option of
specifying this filter directly in the tiling aggregation.
This is even more relevant to `geo_shape` where the bounds will restrict
the shape to be within the bounds
this optional `bounds` parameter is parsed in an equivalent fashion to
the bounds specified in the geo_bounding_box query.
Adds support for the `offset` parameter to the `date_histogram` source
of composite aggs. The `offset` parameter is supported by the normal
`date_histogram` aggregation and is useful for folks that need to
measure things from, say, 6am one day to 6am the next day.
This is implemented by creating a new `Rounding` that knows how to
handle offsets and delegates to other rounding implementations. That
implementation doesn't fully implement the `Rounding` contract, namely
`nextRoundingValue`. That method isn't used by composite aggs so I can't
be sure that any implementation that I add will be correct. I propose to
leave it throwing `UnsupportedOperationException` until I need it.
Closes#48757
James Rodewig
Howard
Igor Motov
Nik Everett
István Zoltán Szabó
Adam Locke
Christos Soulios
David Kyle
Tal Levy
Benjamin Trent
Gabriel Petrovay
Ignacio Vera
Zachary Tong
Gil Raphaelli
Paweł Krześniak
Lisa Cawley
Anton Dollmaier