Query Tags¶

Introduction¶

Query Tags are SQL comments which are made up of (key=value) pairs that are appended to the SQL statements generated by Hasura for GraphQL operations. This enables the ability to get some application context in the database logs and also use native database monitoring tools (e.g. pganalyze) for better performance analysis.

Example:

When the following query is sent to Hasura

query GetChild {
  child {
    name
  }
}

Hasura attaches query tags (unless disabled) to the generated SQL statement it sends to the database.

SELECT name FROM child /* request_id=487c2ed5-08a4-429a-b0e0-4666a82e3cc6, field_name=child, operation_name=GetChild */

Formats of Query Tags¶

The format of the Query Tags describes how the (Key,Value) pairs are constructed. Currently we support two formats of Query Tags:

1. Standard (standard)
2. SQLCommenter (sqlcommenter)

SELECT name FROM child /* request_id=487c2ed5-08a4-429a-b0e0-4666a82e3cc6, field_name=child, parameterized_query_hash=b2a71ce23928ca7f0021f9060e5d590e9f9bb00f, operation_name=GetChild */

SELECT name FROM child /* field_name='child', operation_name='GetChild', parameterized_query_hash='b2a71ce23928ca7f0021f9060e5d590e9f9bb00f' ,  request_id='487c2ed5-08a4-429a-b0e0-4666a82e3cc6' */

Information in Query Tags¶

The following information is present in query tags for the GraphQL operations.

Metadata Specification¶

sources:
  name: # Name of the source
  configuration :
  query_tags: # Optional Field
    disabled: # Optional Field | Type: Bool | Values: true or false
    format:   # Optinal Field  | Values: standard or sqlcommenter

In the above metadata spec:

1. The query_tags field is optional. If the query_tags field is not present for a source, then query tags is enabled for the source and the format used is standard.
2. To disable query tags for any source, set the value of disabled field to true.
3. To override the default format (Standard) for query tags, use the format field.

Example Metadata Specification¶

sources:
  - name: test_db
    configuration:
    query_tags:
      disabled: true

  - name: hasura_db_herokou
      configuration:
      query_tags:
        format: sqlcommenter

  - name: hasura_db_2
      configuration:
      query_tags:
        format: standard
        disabled: true

Metadata API To Set Query Tags¶

type: "set_query_tags"
args:
  source_name: # Name of the source | Required
  disabled:    # Optional Field | Type: Bool | Values: true or false
  format:      # Optinal Field  | Values: standard or sqlcommenter