62 lines
1.7 KiB
Plaintext
62 lines
1.7 KiB
Plaintext
[[ignore-above]]
|
|
=== `ignore_above`
|
|
|
|
Strings longer than the `ignore_above` setting will not be indexed or stored.
|
|
For arrays of strings, `ignore_above` will be applied for each array element separately and string elements longer than `ignore_above` will not be indexed or stored.
|
|
|
|
NOTE: All strings/array elements will still be present in the `_source` field, if the latter is enabled which is the default in Elasticsearch.
|
|
|
|
[source,js]
|
|
--------------------------------------------------
|
|
PUT my_index
|
|
{
|
|
"mappings": {
|
|
"_doc": {
|
|
"properties": {
|
|
"message": {
|
|
"type": "keyword",
|
|
"ignore_above": 20 <1>
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
PUT my_index/_doc/1 <2>
|
|
{
|
|
"message": "Syntax error"
|
|
}
|
|
|
|
PUT my_index/_doc/2 <3>
|
|
{
|
|
"message": "Syntax error with some long stacktrace"
|
|
}
|
|
|
|
GET _search <4>
|
|
{
|
|
"aggs": {
|
|
"messages": {
|
|
"terms": {
|
|
"field": "message"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
--------------------------------------------------
|
|
// CONSOLE
|
|
<1> This field will ignore any string longer than 20 characters.
|
|
<2> This document is indexed successfully.
|
|
<3> This document will be indexed, but without indexing the `message` field.
|
|
<4> Search returns both documents, but only the first is present in the terms aggregation.
|
|
|
|
TIP: The `ignore_above` setting can be updated on
|
|
existing fields using the <<indices-put-mapping,PUT mapping API>>.
|
|
|
|
This option is also useful for protecting against Lucene's term byte-length
|
|
limit of `32766`.
|
|
|
|
NOTE: The value for `ignore_above` is the _character count_, but Lucene counts
|
|
bytes. If you use UTF-8 text with many non-ASCII characters, you may want to
|
|
set the limit to `32766 / 4 = 8191` since UTF-8 characters may occupy at most
|
|
4 bytes.
|