elasticsearch/docs/reference/query-languages/esql/limitations.md

navigation_title	mapped_pages
Limitations	https://www.elastic.co/guide/en/elasticsearch/reference/current/esql-limitations.html

{{esql}} limitations [esql-limitations]

Result set size limit [esql-max-rows]

By default, an {{esql}} query returns up to 1,000 rows. You can increase the number of rows up to 10,000 using the LIMIT command.

:::{include} _snippets/common/result-set-size-limitation.md :::

Field types [esql-supported-types]

Supported types [_supported_types]

{{esql}} currently supports the following field types:

• alias

• boolean

• date

• date_nanos (Tech Preview)

  • The following functions don’t yet support date nanos: bucket, date_format, date_parse, date_diff, date_extract
  • You can use to_datetime to cast to millisecond dates to use unsupported functions

• double (float, half_float, scaled_float are represented as double)

• ip

• keyword family including keyword, constant_keyword, and wildcard

• int (short and byte are represented as int)

• long

• null

• text family including text, semantic_text and match_only_text

• [preview] unsigned_long

• version

• Spatial types

  • geo_point
  • geo_shape
  • point
  • shape

Unsupported types [_unsupported_types]

{{esql}} does not yet support the following field types:

• TSDB metrics

  • counter
  • position
  • aggregate_metric_double

• Date/time

  • date_range

• Other types

  • binary
  • completion
  • dense_vector
  • double_range
  • flattened
  • float_range
  • histogram
  • integer_range
  • ip_range
  • long_range
  • nested
  • rank_feature
  • rank_features
  • search_as_you_type

Querying a column with an unsupported type returns an error. If a column with an unsupported type is not explicitly used in a query, it is returned with null values, with the exception of nested fields. Nested fields are not returned at all.

Limitations on supported types [_limitations_on_supported_types]

Some field types are not supported in all contexts:

• Spatial types are not supported in the SORT processing command. Specifying a column of one of these types as a sort parameter will result in an error:

  • geo_point
  • geo_shape
  • cartesian_point
  • cartesian_shape

In addition, when querying multiple indexes, it’s possible for the same field to be mapped to multiple types. These fields cannot be directly used in queries or returned in results, unless they’re explicitly converted to a single type.

_source availability [esql-_source-availability]

{{esql}} does not support configurations where the _source field is disabled.

Full-text search [esql-limitations-full-text-search]

One limitation of full-text search is that it is necessary to use the search function, like MATCH, in a WHERE command directly after the FROM source command, or close enough to it. Otherwise, the query will fail with a validation error.

For example, this query is valid:

FROM books
| WHERE MATCH(author, "Faulkner") AND MATCH(author, "Tolkien")

But this query will fail due to the STATS command:

FROM books
| STATS AVG(price) BY author
| WHERE MATCH(author, "Faulkner")

Note that, because of the way {{esql}} treats text values, any queries on text fields that do not explicitly use the full-text functions, MATCH, QSTR or KQL, will behave as if the fields are actually keyword fields: they are case-sensitive and need to match the full string.

text fields behave like keyword fields [esql-limitations-text-fields]

While {{esql}} supports text fields, {{esql}} does not treat these fields like the Search API does. {{esql}} queries do not query or aggregate the analyzed string. Instead, an {{esql}} query will try to get a text field’s subfield of the keyword family type and query/aggregate that. If it’s not possible to retrieve a keyword subfield, {{esql}} will get the string from a document’s _source. If the _source cannot be retrieved, for example when using synthetic source, null is returned.

Once a text field is retrieved, if the query touches it in any way, for example passing it into a function, the type will be converted to keyword. In fact, functions that operate on both text and keyword fields will perform as if the text field was a keyword field all along.

For example, the following query will return a column greatest of type keyword no matter whether any or all of field1, field2, and field3 are of type text:

| FROM index
| EVAL greatest = GREATEST(field1, field2, field3)

Note that {{esql}}'s retrieval of keyword subfields may have unexpected consequences. Other than when explicitly using the full-text functions, MATCH and QSTR, any {{esql}} query on a text field is case-sensitive.

For example, after indexing a field of type text with the value Elasticsearch query language, the following WHERE clause does not match because the LIKE operator is case-sensitive:

| WHERE field LIKE "elasticsearch query language"

The following WHERE clause does not match either, because the LIKE operator tries to match the whole string:

| WHERE field LIKE "Elasticsearch"

As a workaround, use wildcards and regular expressions. For example:

| WHERE field RLIKE "[Ee]lasticsearch.*"

Furthermore, a subfield may have been mapped with a normalizer, which can transform the original string. Or it may have been mapped with ignore_above, which can truncate the string. None of these mapping operations are applied to an {{esql}} query, which may lead to false positives or negatives.

To avoid these issues, a best practice is to be explicit about the field that you query, and query keyword sub-fields instead of text fields. Or consider using one of the full-text search functions.

Using {{esql}} to query multiple indices [esql-multi-index-limitations]

As discussed in more detail in Using {{esql}} to query multiple indices, {{esql}} can execute a single query across multiple indices, data streams, or aliases. However, there are some limitations to be aware of:

• All underlying indexes and shards must be active. Using admin commands or UI, it is possible to pause an index or shard, for example by disabling a frozen tier instance, but then any {{esql}} query that includes that index or shard will fail, even if the query uses WHERE to filter out the results from the paused index. If you see an error of type search_phase_execution_exception, with the message Search rejected due to missing shards, you likely have an index or shard in UNASSIGNED state.
• The same field must have the same type across all indexes. If the same field is mapped to different types it is still possible to query the indexes, but the field must be explicitly converted to a single type.

Time series data streams are not supported [esql-tsdb]

{{esql}} does not support querying time series data streams (TSDS).

Date math limitations [esql-limitations-date-math]

Date math expressions work well when the leftmost expression is a datetime, for example:

now() + 1 year - 2hour + ...

But using parentheses or putting the datetime to the right is not always supported yet. For example, the following expressions fail:

1year + 2hour + now()
now() + (1year + 2hour)

Date math does not allow subtracting two datetimes, for example:

now() - 2023-10-26

Enrich limitations [esql-limitations-enrich]

While all three enrich policy types are supported, there are some limitations to be aware of:

• The geo_match enrich policy type only supports the intersects spatial relation.
• It is required that the match_field in the ENRICH command is of the correct type. For example, if the enrich policy is of type geo_match, the match_field in the ENRICH command must be of type geo_point or geo_shape. Likewise, a range enrich policy requires a match_field of type integer, long, date, or ip, depending on the type of the range field in the original enrich index.
• However, this constraint is relaxed for range policies when the match_field is of type KEYWORD. In this case the field values will be parsed during query execution, row by row. If any value fails to parse, the output values for that row will be set to null, an appropriate warning will be produced and the query will continue to execute.

Dissect limitations [esql-limitations-dissect]

The DISSECT command does not support reference keys.

Grok limitations [esql-limitations-grok]

The GROK command does not support configuring custom patterns, or multiple patterns. The GROK command is not subject to Grok watchdog settings.

Multivalue limitations [esql-limitations-mv]

{{esql}} supports multivalued fields, but functions return null when applied to a multivalued field, unless documented otherwise. Work around this limitation by converting the field to single value with one of the multivalue functions.

Timezone support [esql-limitations-timezone]

{{esql}} only supports the UTC timezone.

Kibana limitations [esql-limitations-kibana]

• The user interface to filter data is not enabled when Discover is in {{esql}} mode. To filter data, write a query that uses the WHERE command instead.
• Discover shows no more than 10,000 rows. This limit only applies to the number of rows that are retrieved by the query and displayed in Discover. Queries and aggregations run on the full data set.
• Discover shows no more than 50 columns. If a query returns more than 50 columns, Discover only shows the first 50.
• CSV export from Discover shows no more than 10,000 rows. This limit only applies to the number of rows that are retrieved by the query and displayed in Discover. Queries and aggregations run on the full data set.
• Querying many indices at once without any filters can cause an error in kibana which looks like [esql] > Unexpected error from Elasticsearch: The content length (536885793) is bigger than the maximum allowed string (536870888). The response from {{esql}} is too long. Use DROP or KEEP to limit the number of fields returned.