Azure CosmosDB 通过特定页码获取分页数据

Question

背景：FastAPI + CosmosDB

CosmosDB python SDK 的 official pagination code example 如下所示。它只展示了如何通过页面迭代器获取下一页。如何通过特定页码获取分页数据？

 def test_paging_with_continuation_token(self):
    created_collection = self.config.create_multi_partition_collection_with_custom_pk_if_not_exist(self.client)

    document_definition = {'pk': 'pk', 'id': '1'}
    created_collection.create_item(body=document_definition)
    document_definition = {'pk': 'pk', 'id': '2'}
    created_collection.create_item(body=document_definition)

    query = 'SELECT * from c'
    query_iterable = created_collection.query_items(
        query=query,
        partition_key='pk',
        max_item_count=1
    )
    pager = query_iterable.by_page()
    pager.next()
    token = pager.continuation_token
    second_page = list(pager.next())[0]

    pager = query_iterable.by_page(token)
    second_page_fetched_with_continuation_token = list(pager.next())[0]

    self.assertEqual(second_page['id'], second_page_fetched_with_continuation_token['id'])

Answer 1

要按特定页码分页，您可以使用 Cosmos DB 中可用的 OFFSET LIMIT 子句 SQL API.

您需要做的就是在查询本身中指定 offset 和 limit 子句。类似于：

query = 'SELECT * from c OFFSET 1 LIMIT 1'

但是，请注意使用 OFFSET/LIMIT 会显着增加 RU 消耗。来自同一个 link:

The RU charge of a query with OFFSET LIMIT will increase as the number of terms being offset increases. For queries that have multiple pages of results, we typically recommend using continuation tokens. Continuation tokens are a "bookmark" for the place where the query can later resume. If you use OFFSET LIMIT, there is no "bookmark". If you wanted to return the query's next page, you would have to start from the beginning.

Azure CosmosDB 通过特定页码获取分页数据

Azure CosmosDB get pagination data by a specific page number

python

pagination

azure-cosmosdb

fastapi