DataPlaneRequests (Diagnostic Log)
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Category: Maintenance & Security
Summary: Logs item-level create/read/replace/delete/query operations with RU charge and duration.
Overview
DataPlaneRequests is a diagnostic log table that logs individual data-plane operations — such as item creates, reads, replaces, deletes, and queries — executed against an Azure Cosmos DB for NoSQL account, including details like RU charge, status code, and duration per request. It complements ControlPlaneRequests (which logs account-level administrative operations) by giving request-level visibility into the actual application traffic hitting the account, useful for deep troubleshooting of latency, throttling (429s), or unexpected RU charges. In Log Analytics, this table is exposed under the name CDBDataPlaneRequests.
Example (KQL): Find the most expensive queries and their text
CDBDataPlaneRequests
| where todouble(RequestCharge) > 10.0
| project ActivityId, RequestCharge
| join kind=inner (
CDBQueryRuntimeStatistics
| project ActivityId, QueryText
) on $left.ActivityId == $right.ActivityId
| order by RequestCharge desc
| limit 100
This query joins CDBDataPlaneRequests (RU charge per request) with CDBQueryRuntimeStatistics (the query text) on the shared ActivityId, filters for requests costing more than 10 RUs, and returns the 100 most expensive queries together with their full query text — a common first step when troubleshooting unexpectedly high RU consumption.
More Info & Links
DP-420 Style Practice Questions
Q1. What does the DataPlaneRequests diagnostic log table capture?
- A. Individual item-level operations (create, read, replace, delete, query) with details like RU charge and duration
- B. Account-level operations such as adding or removing regions
- C. Aggregated per-second RU consumption by partition key
- D. Estimated logical partition storage size
Q2. How does DataPlaneRequests differ from ControlPlaneRequests?
- A. DataPlaneRequests logs item-level operations (application traffic), while ControlPlaneRequests logs account-level administrative operations
- B. DataPlaneRequests only logs failed requests, while ControlPlaneRequests logs successful ones
- C. DataPlaneRequests is only available for the MongoDB API
- D. There is no difference; they are aliases for the same table
Answer Key
Answers are listed at the very end so you can attempt the questions first.
- Q1 (DataPlaneRequests (Diagnostic Log)): A. Individual item-level operations (create, read, replace, delete, query) with details like RU charge and duration — DataPlaneRequests logs per-request data-plane operation details, including RU charge, status code, and duration.
- Q2 (DataPlaneRequests (Diagnostic Log)): A. DataPlaneRequests logs item-level operations (application traffic), while ControlPlaneRequests logs account-level administrative operations — DataPlaneRequests covers item-level read/write/query operations, whereas ControlPlaneRequests covers account/administrative changes.
DP-420: Designing and Implementing Cloud-Native Applications Using Microsoft Azure Cosmos DB — term detail page
