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Row Fetch Limit

Introduction

Limit the number of rows returned in a response on select operations.

You can set a row fetch limit on the Hasura Console in Data -> [table] -> Permissions -> select -> Row select permissions -> Limit number of rows as per the image below:

<Thumbnail src="/img/auth/authorization_row-fetch-limit_2-16-1.png" alt="Row fetch limit" width="450px" />

You can set a row fetch limit for a table in the metadata -> databases -> [database-name] -> tables -> [table-name].yaml file, eg:

- table:
    schema: public
    name: users
  select_permissions:
    - role: user
      permission:
        columns:
          - id
          - name
        filter:
          user_id:
            _eq: X-Hasura-User-Id
        limit: 1

Apply the Metadata by running:

hasura metadata apply

You can set a row fetch limit for a table when using the permissions Metadata API. Example using a Postgres db:

POST /v1/metadata HTTP/1.1
Content-Type: application/json
X-Hasura-Role: admin

{
   "type": "pg_create_select_permission",
   "args": {
      "source": "<db_name>",
      "table": "users",
      "role": "user",
      "permission": {
         "columns": "*",
         "filter": {
            "id": {
               "_eq": "X-Hasura-User-Id"
            }
         },
         "limit": 1
      }
   }
}

In the above example, this configuration restricts the number of accessible rows (based on the row permission: {"id":{"_eq":"X-Hasura-User-Id"}}) to 1.

Setting row fetch limits is useful for preventing abuse of your API especially if it is exposed to the public. You can also configure other limits.