问：Azure Cosmos DB Graph：当索引策略定义为手动时，如何在Graph API中运行查询？

Question

In Cosmos DB graph when I am defining Indexing policy as Automatic, I am able to run queries but when I am updating indexing policy to Manual and defining Indexing path (/label/?) and Indexing mode set as 'Consistent', the query is not fetching any data.

Let's say my first query (when Indexing policy set as Manual) is :

g.addV('Azure').property('name','Cerulean Software'))

Result is :

[
    {
        "id": "0c14a00a-edf6-46b1-9e40-45cc37f750ea",
        "label": "Azure",
        "type": "vertex",
        "properties": {
            "name": [
                {
                    "id": "f89ee2ee-74df-4256-a5d4-2b47eb526976",
                    "value": "Cerulean Software"
                }
            ]
        }
    }
]

Now, my second query (when Indexing policy set as Manual (see Edit #1 below)) is:

g.V().hasLabel('Azure')

This second query is not fetching any result even though there is vertex present in graph named as 'Azure'.

What could be the possible reason behind this?

Edit #1: Manual Indexing Policy Before Change

"indexingPolicy": {
    "automatic": false,
    "excludedPaths": [],
    "includedPaths": [
        {
            "path": "/*",
            "indexes": [
                {
                    "dataType": "Number",
                    "kind": "Range",
                    "precision": -1
                },
                {
                    "dataType": "String",
                    "kind": "Hash",
                    "precision": 3
                }
            ]
        },
        {
            "path": "/label/?",
            "indexes": [
                {
                    "dataType": "String",
                    "kind": "Hash",
                    "precision": 3
                },
                {
                    "dataType": "Number",
                    "kind": "Range",
                    "precision": -1
                }
            ]
        }
    ],
    "indexingMode": "consistent"
},

Edit #2: Manual Indexing Policy After Change

"indexingPolicy": {
    "automatic": false,
    "excludedPaths": [],
    "includedPaths": [
        {
            "path": "/*",
            "indexes": [
                {
                    "dataType": "Number",
                    "kind": "Range",
                    "precision": -1
                },
                {
                    "dataType": "String",
                    "kind": "Hash",
                    "precision": 3
                }
            ]
        },
        {
            "path": "/_isEdge/?",
            "indexes": [
                {
                    "dataType": "String",
                    "kind": "Hash",
                    "precision": 3
                },
                {
                    "dataType": "Number",
                    "kind": "Range",
                    "precision": -1
                }
            ]
        }
    ],
    "indexingMode": "consistent"
},

Answer 1

With Cosmos, graph statements are not executed as traversals on the Azure side. The graph client actually translates gremlin statements into Document SQL calls and then aggregates the results back to you on the client side. In the case of your statement gV().hasLabel('Azure') the call is actually translated to {"query":"SELECT N_2 FROM Node N_2 WHERE (IS_DEFINED(N_2._isEdge) = false AND (N_2.label = 'Azure'))"}

This can be verified through the use of a proxy such as Fiddler which will allow you to inspect the outbound calls from your machine.

The top level _isEdge property seems to be used across almost all Gremlin translated queries so I suspect that if you add that property to your indexing policy you should start to see the expected results.

EDIT: I originally missed the part of your indexing policy that sets automatic: false . According to the Cosmos docs (under the heading Opting in and opting out of indexing ), By default, all documents are automatically indexed, but you can choose to turn it off. When indexing is turned off, documents can be accessed only through their self-links or by queries using ID. By default, all documents are automatically indexed, but you can choose to turn it off. When indexing is turned off, documents can be accessed only through their self-links or by queries using ID.

If you choose to run with indexing turned off, then the rest of your indexing policy is effectively meaningless and queries that aren't directly by document Id will no longer work. Can you elaborate as to what you're actually trying to accomplish here? There seems to be a bit of confusion. The indexing settings you've placed on label and isEdge aren't even necessary because they are the same as the value you've put for * which is the default rule matching all paths.

Post what your goals are for your indexing strategy and I can try to make an appropriate recommendation but you're definitely going to want to put automatic: true back into your policy.