Understanding the x-ms-resource-usage in DocumentDB response header

问题

While performing a simple Get operation by Id where a single document is returned (not an array with one document) I get the following x-ms-resource-usage:

x-ms-resource-usage:documentSize:0;documentsSize:288;collectionSize=307;

Questions:

• Why is documentSize 0?
• What is the unit of measure? Bytes?
• What is the difference between documentSize and documentsSize? Please note the query only returns one document.
• What is the collectionSize? Is that the total number of documents in the collection?
• What is the difference between x-ms-resource-usage and x-ms-resource-quota?

回答1:

I'm fairly sure the numbers are as follows, and all in KB:

• documentSize: Size of the document
• documentsSize: Combined size of all documents in collection
• collectionSize: Combined size of all documents in collection, along with overhead such as indexes

x-ms-resource-usage is about consumed resources within the collection, while x-ms-resource-quota is going to give you your limits. So with quota, you'll see documentsSize and collectionSize both set to something like 10485760, which is 10GB (10,485,760 MB).

回答2:

documentSize and documentsSize are the same value - first one in MB and the second one in kB. Apparently, documentSize is being deprecated.

collectionSize = documentsSize+metadata (in kB)

来源：https://stackoverflow.com/questions/35274760/understanding-the-x-ms-resource-usage-in-documentdb-response-header