Ontology entities are not visible in Graph
I have a problem with some entities in my ontology. I created an ontology item and added some tables. Note this was still the old experience of the ontology item. I use it as a source for my Fabric Data Agent and it worked fine. (Reason for using the old version of the ontology is because the new version can't seem to be connected yet.) Now the problem comes. I added some more tables from a different lakehouse to the ontology later on. I can see the data of these tables in the ontology item when I look at instances. However, when I ask the Fabric Data Agent it can't seem to query those entities. When I look at the graph item that the ontology created I see that it only contains the tables that I added at the start, but not the ones that were added later. Does anybody have any idea how this could occur? I tried refreshing the Graph item but that doesn't seem to solve the problem.Ontology entities are not visible in Graph
I have a problem with some entities in my ontology. I created an ontology item and added some tables. Note this was still the old experience of the ontology item. I use it as a source for my Fabric Data Agent and it worked fine. (Reason for using the old version of the ontology is because the new version can't seem to be connected yet.) Now the problem comes. I added some more tables from a different lakehouse to the ontology later on. I can see the data of these tables in the ontology item when I look at instances. However, when I ask the Fabric Data Agent it can't seem to query those entities. When I look at the graph item that the ontology created I see that it only contains the tables that I added at the start, but not the ones that were added later. Does anybody have any idea how this could occur? I tried refreshing the Graph item but that doesn't seem to solve the problem.
Ontology New Experience: Data Agent and Graph Materialization Issues
Hello, I am currently evaluating the Fabric Ontology new experience (Generation 2, Preview) and have encountered three issues. I would like to confirm whether these are known limitations of the current Preview or unexpected issues. Environment: Microsoft Fabric capacity: F2 Ontology: New experience (Generation 2, Preview) Data sources: Lakehouse and Eventhouse Unable to add an Ontology to Fabric Data Agent When I try to add an Ontology created with the new experience as a data source to a Fabric Data Agent, the operation fails with the following error: Error occurred while adding datasource. Failed to fetch schema for the data source. To isolate the issue, I simplified the Ontology to contain only a single Shop entity and removed all Decimal properties and time-series bindings. Graph materialization completes successfully with this configuration, but adding the same Ontology to the Data Agent still fails. In the same environment, an Ontology created with the old experience (Generation 1) can be added to the Data Agent successfully. Therefore, the Data Agent issue does not appear to be caused by a Graph materialization failure. Graph materialization fails when a Decimal property exists When an entity contains a Decimal property, Graph materialization fails with HTTP 400. In my test, the Shop entity contained the following property: Property: FloorAreaM2 Type: Decimal The following error occurs: FeatureNotImplemented: DECIMAL(P,S) graph properties are not enabled. After removing the FloorAreaM2 property from the Ontology, Graph materialization completes successfully. I would like to confirm whether Decimal properties are currently unsupported for Graph materialization in the Ontology new experience. Graph materialization fails when a time-series binding exists Graph materialization also fails when a time-series binding is added to an entity. To isolate the issue, I reduced the time-series binding to only one property: Entity: Shop Source: TS_SalesHeader (Eventhouse) Property: SalesId Property type: Time series (Integer) Timestamp: SalesDateTime Even with only this single Integer time-series property, Graph materialization fails with HTTP 400. The following error occurs: ModelValidationError: InvalidPropertyType GraphType: Property type INVALID for property SalesId is invalid. If I remove the time-series binding from the same Ontology, Graph materialization completes successfully. I also tested additional time-series properties, and Graph materialization failed regardless of their underlying data types. Therefore, this does not appear to be an issue specific to Decimal properties. Could you please clarify the following? Is the Fabric Ontology new experience (Generation 2, Preview) currently supported as a data source for Fabric Data Agent? Are Decimal properties currently supported when materializing an Ontology to Graph? Are time-series bindings currently supported when materializing an Ontology to Graph? If these scenarios are supported, are these known issues with the current Preview? Are there any known workarounds or planned fixes? Thank you.Ontology New Experience: Data Agent and Graph Materialization Issues
Hello, I am currently evaluating the Fabric Ontology new experience (Generation 2, Preview), and I have encountered the following three issues. I would like to confirm whether these behaviors are known limitations of the current Preview or unexpected issues. Environment Microsoft Fabric capacity: F2 Ontology: New experience (Generation 2, Preview) Data sources: Lakehouse and Eventhouse 1. Unable to add an Ontology to Fabric Data Agent When I try to add an Ontology created with the new experience as a data source to a Fabric Data Agent, the operation fails with the following error: Error occurred while adding datasource. Failed to fetch schema for the data source. To isolate the issue, I simplified the Ontology to contain only a single Shop entity and removed all Decimal properties and time-series bindings. With this minimal configuration, Graph materialization completes successfully. However, adding the same Ontology to the Data Agent still fails with "Failed to fetch schema for the data source. In the same environment, an Ontology created with the old experience (Generation 1) can be added to the Data Agent successfully. Therefore, the Data Agent issue does not appear to be caused by a Graph materialization failure. 2. Graph materialization fails when a Decimal property exists When an entity contains a Decimal property, Graph materialization fails with HTTP 400. For example, my Shop entity contained the following property: Property: FloorAreaM2 Type: Decimal Graph materialization failed with the following error: FeatureNotImplemented: DECIMAL(P,S) graph properties are not enabled. After removing the FloorAreaM2 property from the Ontology, Graph materialization completed successfully. I would like to confirm whether Decimal properties are currently unsupported for Graph materialization in the Ontology new experience. 3. Graph materialization fails when a time-series binding exists Graph materialization also fails when I add a time-series binding to an entity. To isolate this issue, I reduced the time-series binding to only one property: Entity: Shop Source: TS_SalesHeader (Eventhouse) Property: SalesId Property type: Time series (Integer) Timestamp: SalesDateTime Even with only this single Integer time-series property, Graph materialization fails with HTTP 400: ModelValidationError: [InvalidPropertyType] GraphType: Property type INVALID for property SalesId is invalid. If I remove the time-series binding from the same Ontology, Graph materialization completes successfully. I also tested additional time-series properties, and the properties were reported as GraphType INVALID regardless of their underlying data types. Therefore, this does not appear to be an issue specific to Decimal properties. Could you please clarify the following? Is the Fabric Ontology new experience (Generation 2, Preview) currently supported as a data source for Fabric Data Agent? Are Decimal properties currently supported when materializing an Ontology to Graph? Are time-series bindings currently supported when materializing an Ontology to Graph? If these scenarios are supported, are these known issues with the current Preview? Are there any known workarounds or planned fixes? Summary of test results Ontology Generation 1 -> Data Agent: Success Ontology new experience with only a single entity and static data binding, with no Decimal properties or time-series bindings -> Graph materialization: Success Same Ontology -> Data Agent: Failed ("Failed to fetch schema for the data source.") Ontology new experience with a Decimal property -> Graph materialization: Failed ("DECIMAL(P,S) graph properties are not enabled.") Ontology new experience with one Time series (Integer) property -> Graph materialization: Failed ("GraphType: Property type INVALID for property SalesId is invalid.")
Fabric Data Agent on Ontology Fails for Simple and Multi‑Entity Queries (GROUP BY/Aggregation Error)
Hi, I’ve created a Fabric Data Agent using an Ontology as the data source, and I’m encountering consistent failures even when asking simple questions related to a single entity. Queries that span or join multiple entities also fail. Below are the details and the error output. Issue Summary When I ask a basic question (even involving only one entity), the agent returns an error. For multi-entity questions, it fails with the same pattern. The error indicates that the generated Ontology query includes invalid aggregation or grouping logic. Specifically, a field is referenced without being part of the GROUP BY clause or wrapped in an aggregation function. The underlying generated query seems to have a syntax or grouping issue and cannot execute. Query Output: Failed to execute step (RAID: 36eb1c04-9e56-4998-89ac-a9a56919482d). Error: Failed to execute Ontology query with error: "The query is invalid. Reason: BadRequest. Resource: Graph query (graphModelId=9231e6f0-87b9-44b4-9a36-5ddbe39b8d78). InternalCode: 42000. Message: syntax error or access rule violation. Cause: data exception; The identifier node_production_plant.plant_id cannot be used, as it is neither part of the GROUP BY nor an aggregation." I have already enabled "Support GROUP BY in GQL" in the Data Agent instructions. What I need help with: Has anyone seen similar Ontology-based Data Agent failures related to GROUP BY or aggregation? Is this a known limitation or bug when using Fabric Data Agent on Ontology models? Any best practices or modeling patterns to avoid such query-generation errors? Are there known workarounds to ensure the agent produces valid Ontology queries? I can share more examples or screenshots if needed. Thanks in advance for any guidance!
Data Agent fails to query Ontology
Hello, I’m experiencing an error when using the Data Agent in Microsoft Fabric to query my Ontology. Even when I ask very simple questions, the Data Agent fails every time with the following error: Failed to execute step (RAID: "GUID"). Error: Failed to generate NL2Ontology query with error "{"code":"InternalError","subCode":0,"message":"An internal error occurred.","timeStamp":"2026-04-20T13:00:42.7677176Z","httpStatusCode":500,"hresult":-2147467259,"details":[{"code":"RootActivityId","message":"GUID"},{"code":"Param1","message":"Failed to translate NL query to ontology query."}]}" This was working correctly until last week, but for the past four days it has consistently failed with the error above, without any changes on my side. The Data Agent works perfectly when querying: a Lakehouse (NL2SQL), and a Semantic Model (NL2DAX). The issue occurs only when the Ontology is used as the data source. Also I have "Support GROUP BY in GQL" inside the data agent's instructions. Could someone please help me understand what might have changed recently or how to troubleshoot this issue? Thank you in advance.
Unable to add Ontology as a Data Source in Fabric Data Agent (Japan West Region)
I am experiencing an issue where I cannot add an Ontology item as a data source to a Fabric Data Agent. Environment: Region: Japan West Capacity: F2 (Paid) Items: Ontology (preview), Fabric Data Agent Steps to reproduce: Create an Ontology item with entity types and data bindings (Lakehouse). Wait for Graph child artifact initialization to complete. Create a new Fabric Data Agent. Attempt to add the Ontology as a data source. Error message appears: "Couldn't add data source" What works: Adding a Lakehouse directly as a data source works without any issues. All required tenant settings are enabled (Ontology preview, Copilot and Azure OpenAI, cross-geo processing, etc.) Copilot capacity is configured correctly. What fails: Adding an Ontology item as a data source always fails. Error details retrieved from browser DevTools (Network tab): The POST request to the datasources endpoint returns HTTP 202 Accepted. Following the Location header returns the following error response: xmlCopy <TridentPublicApiErrorResponse> <errorCode>RequestFailed</errorCode> <message>Unable to process the request</message> <requestId>XXXX</requestId> <isRetriable>false</isRetriable> </TridentPublicApiErrorResponse> Suspected cause: The Fabric IQ Ontology and Data Agent integration may not be fully supported in the Japan West region at the backend level, as the API returns isRetriable: false, indicating this is not a transient error. Request: Please investigate whether the Ontology-to-Data-Agent integration is supported in the Japan West region, and advise on any workaround or expected timeline for support.Microsoft Fabric Data Agent – HttpClient.Timeout after 300 seconds: where is it configured?
Hi everyone, this post is a follow-up to a previous discussion I opened about Fabric Data Agent queries being cancelled during aggregations: https://community.fabric.microsoft.com/t5/IQ/Fabric-Data-Agent-Query-cancelled-on-aggregations/td-p/5357096 After further testing, I believe I have isolated the issue more clearly, so I am opening a new post with a more specific title and description. The goal is also to make the issue easier to find for anyone searching for HttpClient.Timeout, 300 seconds, or Microsoft Fabric Data Agent timeout problems. The main issue is the following: Some Microsoft Fabric Data Agent requests fail after approximately 300 seconds because of HttpClient.Timeout. I am using a Fabric Data Agent with a Microsoft Fabric Ontology as its data source. The problem mainly appears on expensive queries, especially aggregations and queries involving larger portions of the ontology. However, further experiments suggest that this is not simply a query-performance or capacity issue. I have different Data Agents using the same underlying Ontology. One agent can execute queries for much longer than 5 minutes, in some cases close to 20 minutes. Another agent consistently fails after approximately 5 minutes with an HttpClient.Timeout. Fabric Capacity does not appear to be close to saturation when the timeout occurs. Individual entities can be queried correctly. This makes the fixed approximately 300-second behavior particularly confusing. The question I am now trying to answer is very specific: Which component in the Microsoft Fabric Data Agent architecture is enforcing this HttpClient.Timeout? For example, is the timeout defined in: the Data Agent orchestration layer, the MCP server associated with the published Data Agent, an internal Fabric service calling the ontology or graph engine, the client consuming the agent, or another intermediate HTTP layer? And, most importantly: Is this 300-second HttpClient.Timeout configurable anywhere? I have found other timeout-related settings in the surrounding architecture, but I have not found documentation identifying a setting that clearly corresponds to this specific timeout. There is also another important behavior that I would like to understand. If the published Data Agent is consumed programmatically, for example from a notebook or through its MCP endpoint, does the same 300-second HttpClient.Timeout still apply? Or does that use a different execution path with different timeout constraints? At this point I am specifically trying to identify the architectural source of the timeout rather than optimize the generated GQL query. The most useful clarification would therefore be: Where exactly is the 300-second HttpClient.Timeout enforced, and is there any supported way to configure it or use an execution path that does not have the same limit? This is related to my previous thread about query cancellation during aggregations, but the additional tests seem to narrow the issue down specifically to the HTTP timeout layer.Ontology: cannot add properties to relationship types
Hi all, I've been building a knowledge-graph project using Fabric's Graph and Ontology (preview), and ran into a limitation: Ontology currently lets you define properties on entity types, but not on relationship types. (I even tried adding edge properties directly on the underlying Graph of the Ontology, not just through the Ontology definition, but that didn't work either. But if I do it just on a Graph which is not tied to an Ontology, everything works.) I'd really like to keep using Ontology specifically, not just fall back to a plain Graph without Ontology. So I'm hoping to understand if this is fixable rather than being told to skip Ontology altogether. A few questions: 1. Is this a known/tracked limitation? 2. Is there a fix planned for it? 3. Is there a recommended way to model relationship properties in the meantime? I'm planning to talk about my project publicly, so I'd like to understand if this is expected to change soon or if I should plan around it. Thanks for any info you can share.
