extent_id()

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Applies to: ✅ Azure Data Explorer ✅ Azure Monitor ✅ Microsoft Sentinel

Returns a unique identifier that identifies the data shard ("extent") that the current record resides in.

Applying this function to calculated data that isn't attached to a data shard returns an empty guid (all zeros).

Deprecated aliases: extentid()

Syntax

extent_id()

Learn more about syntax conventions.

Returns

A value of type guid that identifies the current record's data shard, or an empty guid (all zeros).

Example

The following example shows how to get a list of all the data shards that have records from an hour ago with a specific value for the column ActivityId. It demonstrates that some query operators (here, the where operator, and also extend and project) preserve the information about the data shard hosting the record.

T
| where Timestamp > ago(1h)
| where ActivityId == 'dd0595d4-183e-494e-b88e-54c52fe90e5a'
| extend eid=extent_id()
| summarize by eid