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Deprecate the sparse_vector field type. (#48368)
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We have not seen much adoption of this experimental field type, and don't see a
clear use case as it's currently designed. This PR deprecates the field type in
7.x. It will be removed from 8.0 in a follow-up PR.
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jtibshirani authored Oct 23, 2019
1 parent 9e9533f commit 2664cbd
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7 changes: 6 additions & 1 deletion docs/reference/mapping/types/sparse-vector.asciidoc
Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@
<titleabbrev>Sparse vector</titleabbrev>
++++

deprecated[7.6, The `sparse_vector` type is deprecated and will be removed in 8.0.]
experimental[]

A `sparse_vector` field stores sparse vectors of float values.
Expand Down Expand Up @@ -38,7 +39,11 @@ PUT my_index
}
}
}
--------------------------------------------------
// TEST[warning:The [sparse_vector] field type is deprecated and will be removed in 8.0.]

[source,console]
--------------------------------------------------
PUT my_index/_doc/1
{
"my_text" : "text1",
Expand All @@ -50,8 +55,8 @@ PUT my_index/_doc/2
"my_text" : "text2",
"my_vector" : {"103": 0.5, "4": -0.5, "5": 1, "11" : 1.2}
}
--------------------------------------------------
// TEST[continued]

Internally, each document's sparse vector is encoded as a binary
doc value. Its size in bytes is equal to
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190 changes: 118 additions & 72 deletions docs/reference/vectors/vector-functions.asciidoc
Original file line number Diff line number Diff line change
Expand Up @@ -5,16 +5,14 @@

experimental[]

These functions are used for
for <<dense-vector,`dense_vector`>> and
<<sparse-vector,`sparse_vector`>> fields.

NOTE: During vector functions' calculation, all matched documents are
linearly scanned. Thus, expect the query time grow linearly
linearly scanned. Thus, expect the query time grow linearly
with the number of matched documents. For this reason, we recommend
to limit the number of matched documents with a `query` parameter.

Let's create an index with the following mapping and index a couple
====== `dense_vector` functions

Let's create an index with a `dense_vector` mapping and index a couple
of documents into it.

[source,console]
Expand All @@ -27,9 +25,6 @@ PUT my_index
"type": "dense_vector",
"dims": 3
},
"my_sparse_vector" : {
"type" : "sparse_vector"
},
"status" : {
"type" : "keyword"
}
Expand All @@ -40,21 +35,21 @@ PUT my_index
PUT my_index/_doc/1
{
"my_dense_vector": [0.5, 10, 6],
"my_sparse_vector": {"2": 1.5, "15" : 2, "50": -1.1, "4545": 1.1},
"status" : "published"
}
PUT my_index/_doc/2
{
"my_dense_vector": [-0.5, 10, 10],
"my_sparse_vector": {"2": 2.5, "10" : 1.3, "55": -2.3, "113": 1.6},
"status" : "published"
}
POST my_index/_refresh
--------------------------------------------------
// TESTSETUP

For dense_vector fields, `cosineSimilarity` calculates the measure of
The `cosineSimilarity` function calculates the measure of
cosine similarity between a given query vector and document vectors.

[source,console]
Expand Down Expand Up @@ -90,8 +85,8 @@ GET my_index/_search
NOTE: If a document's dense vector field has a number of dimensions
different from the query's vector, an error will be thrown.

Similarly, for sparse_vector fields, `cosineSimilaritySparse` calculates cosine similarity
between a given query vector and document vectors.
The `dotProduct` function calculates the measure of
dot product between a given query vector and document vectors.

[source,console]
--------------------------------------------------
Expand All @@ -109,18 +104,24 @@ GET my_index/_search
}
},
"script": {
"source": "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector']) + 1.0",
"source": """
double value = dotProduct(params.query_vector, doc['my_dense_vector']);
return sigmoid(1, Math.E, -value); <1>
""",
"params": {
"query_vector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
"query_vector": [4, 3.4, -0.2]
}
}
}
}
}
--------------------------------------------------

For dense_vector fields, `dotProduct` calculates the measure of
dot product between a given query vector and document vectors.
<1> Using the standard sigmoid function prevents scores from being negative.

The `l1norm` function calculates L^1^ distance
(Manhattan distance) between a given query vector and
document vectors.

[source,console]
--------------------------------------------------
Expand All @@ -138,23 +139,28 @@ GET my_index/_search
}
},
"script": {
"source": """
double value = dotProduct(params.query_vector, doc['my_dense_vector']);
return sigmoid(1, Math.E, -value); <1>
""",
"source": "1 / (1 + l1norm(params.queryVector, doc['my_dense_vector']))", <1>
"params": {
"query_vector": [4, 3.4, -0.2]
"queryVector": [4, 3.4, -0.2]
}
}
}
}
}
--------------------------------------------------

<1> Using the standard sigmoid function prevents scores from being negative.
<1> Unlike `cosineSimilarity` that represent similarity, `l1norm` and
`l2norm` shown below represent distances or differences. This means, that
the more similar the vectors are, the lower the scores will be that are
produced by the `l1norm` and `l2norm` functions.
Thus, as we need more similar vectors to score higher,
we reversed the output from `l1norm` and `l2norm`. Also, to avoid
division by 0 when a document vector matches the query exactly,
we added `1` in the denominator.

Similarly, for sparse_vector fields, `dotProductSparse` calculates dot product
between a given query vector and document vectors.
The `l2norm` function calculates L^2^ distance
(Euclidean distance) between a given query vector and
document vectors.

[source,console]
--------------------------------------------------
Expand All @@ -172,26 +178,77 @@ GET my_index/_search
}
},
"script": {
"source": """
double value = dotProductSparse(params.query_vector, doc['my_sparse_vector']);
return sigmoid(1, Math.E, -value);
""",
"params": {
"query_vector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
"source": "1 / (1 + l2norm(params.queryVector, doc['my_dense_vector']))",
"params": {
"queryVector": [4, 3.4, -0.2]
}
}
}
}
}
--------------------------------------------------

For dense_vector fields, `l1norm` calculates L^1^ distance
(Manhattan distance) between a given query vector and
document vectors.
NOTE: If a document doesn't have a value for a vector field on which
a vector function is executed, an error will be thrown.

You can check if a document has a value for the field `my_vector` by
`doc['my_vector'].size() == 0`. Your overall script can look like this:

[source,js]
--------------------------------------------------
"source": "doc['my_vector'].size() == 0 ? 0 : cosineSimilarity(params.queryVector, doc['my_vector'])"
--------------------------------------------------
// NOTCONSOLE

====== `sparse_vector` functions

deprecated[7.6, The `sparse_vector` type is deprecated and will be removed in 8.0.]

Let's create an index with a `sparse_vector` mapping and index a couple
of documents into it.

[source,console]
--------------------------------------------------
GET my_index/_search
PUT my_sparse_index
{
"mappings": {
"properties": {
"my_sparse_vector": {
"type": "sparse_vector"
},
"status" : {
"type" : "keyword"
}
}
}
}
--------------------------------------------------
// TEST[warning:The [sparse_vector] field type is deprecated and will be removed in 8.0.]

[source,console]
--------------------------------------------------
PUT my_sparse_index/_doc/1
{
"my_sparse_vector": {"2": 1.5, "15" : 2, "50": -1.1, "4545": 1.1},
"status" : "published"
}
PUT my_sparse_index/_doc/2
{
"my_sparse_vector": {"2": 2.5, "10" : 1.3, "55": -2.3, "113": 1.6},
"status" : "published"
}
POST my_sparse_index/_refresh
--------------------------------------------------
// TEST[continued]

The `cosineSimilaritySparse` function calculates cosine similarity
between a given query vector and document vectors.

[source,console]
--------------------------------------------------
GET my_sparse_index/_search
{
"query": {
"script_score": {
Expand All @@ -205,31 +262,24 @@ GET my_index/_search
}
},
"script": {
"source": "1 / (1 + l1norm(params.queryVector, doc['my_dense_vector']))", <1>
"source": "cosineSimilaritySparse(params.query_vector, doc['my_sparse_vector']) + 1.0",
"params": {
"queryVector": [4, 3.4, -0.2]
"query_vector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
}
}
}
}
}
--------------------------------------------------
// TEST[continued]
// TEST[warning:The [sparse_vector] field type is deprecated and will be removed in 8.0.]

<1> Unlike `cosineSimilarity` that represent similarity, `l1norm` and
`l2norm` shown below represent distances or differences. This means, that
the more similar the vectors are, the lower the scores will be that are
produced by the `l1norm` and `l2norm` functions.
Thus, as we need more similar vectors to score higher,
we reversed the output from `l1norm` and `l2norm`. Also, to avoid
division by 0 when a document vector matches the query exactly,
we added `1` in the denominator.

For sparse_vector fields, `l1normSparse` calculates L^1^ distance
The `dotProductSparse` function calculates dot product
between a given query vector and document vectors.

[source,console]
--------------------------------------------------
GET my_index/_search
GET my_sparse_index/_search
{
"query": {
"script_score": {
Expand All @@ -243,23 +293,27 @@ GET my_index/_search
}
},
"script": {
"source": "1 / (1 + l1normSparse(params.queryVector, doc['my_sparse_vector']))",
"params": {
"queryVector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
"source": """
double value = dotProductSparse(params.query_vector, doc['my_sparse_vector']);
return sigmoid(1, Math.E, -value);
""",
"params": {
"query_vector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
}
}
}
}
}
--------------------------------------------------
// TEST[continued]
// TEST[warning:The [sparse_vector] field type is deprecated and will be removed in 8.0.]

For dense_vector fields, `l2norm` calculates L^2^ distance
(Euclidean distance) between a given query vector and
document vectors.
The `l1normSparse` function calculates L^1^ distance
between a given query vector and document vectors.

[source,console]
--------------------------------------------------
GET my_index/_search
GET my_sparse_index/_search
{
"query": {
"script_score": {
Expand All @@ -273,22 +327,24 @@ GET my_index/_search
}
},
"script": {
"source": "1 / (1 + l2norm(params.queryVector, doc['my_dense_vector']))",
"source": "1 / (1 + l1normSparse(params.queryVector, doc['my_sparse_vector']))",
"params": {
"queryVector": [4, 3.4, -0.2]
"queryVector": {"2": 0.5, "10" : 111.3, "50": -1.3, "113": 14.8, "4545": 156.0}
}
}
}
}
}
--------------------------------------------------
// TEST[continued]
// TEST[warning:The [sparse_vector] field type is deprecated and will be removed in 8.0.]

Similarly, for sparse_vector fields, `l2normSparse` calculates L^2^ distance
The `l2normSparse` function calculates L^2^ distance
between a given query vector and document vectors.

[source,console]
--------------------------------------------------
GET my_index/_search
GET my_sparse_index/_search
{
"query": {
"script_score": {
Expand All @@ -311,15 +367,5 @@ GET my_index/_search
}
}
--------------------------------------------------

NOTE: If a document doesn't have a value for a vector field on which
a vector function is executed, an error will be thrown.

You can check if a document has a value for the field `my_vector` by
`doc['my_vector'].size() == 0`. Your overall script can look like this:

[source,js]
--------------------------------------------------
"source": "doc['my_vector'].size() == 0 ? 0 : cosineSimilarity(params.queryVector, doc['my_vector'])"
--------------------------------------------------
// NOTCONSOLE
// TEST[continued]
// TEST[warning:The [sparse_vector] field type is deprecated and will be removed in 8.0.]
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