Ingest from query (.set, .append, .set-or-append, .set-or-replace)

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer

These commands execute a query or a management command and ingest the results of the query into a table. The difference between these commands is how they treat existing or nonexistent tables and data.

Command	If table exists	If table doesn't exist
.set	The command fails.	The table is created and data is ingested.
.append	Data is appended to the table.	The command fails.
.set-or-append	Data is appended to the table.	The table is created and data is ingested.
.set-or-replace	Data replaces the data in the table.	The table is created and data is ingested.

To cancel an ingest from query command, see cancel operation.

Note

Ingest from query is a direct ingestion. As such, it does not include automatic retries. Automatic retries are available when ingesting through the data management service.

Permissions

To perform different actions on a table, you need specific permissions:

• To add rows to an existing table using the .append command, you need a minimum of Table Ingestor permissions.
• To create a new table using the various .set commands, you need a minimum of Database User permissions.
• To replace rows in an existing table using the .set-or-replace command, you need a minimum of Table Admin permissions.

For more information on permissions, see Kusto role-based access control.

Syntax

(.set | .append | .set-or-append | .set-or-replace) [async] tableName [with (propertyName = propertyValue [, ...])] <| queryOrCommand

Learn more about syntax conventions.

Parameters

Name	Type	Required	Description
async	string		If specified, the command returns immediately and continues ingestion in the background. Use the returned OperationId with the .show operations command to retrieve the ingestion completion status and results.
tableName	string	✔️	The name of the table to ingest data into. The tableName is always related to the database in context.
propertyName, propertyValue	string		One or more supported ingestion properties used to control the ingestion process.
queryOrCommand	string	✔️	The text of a query or a management command whose results are used as data to ingest. Only .show management commands are supported.

Performance tips

• Set the distributed property to true if the amount of data produced by the query is large, exceeds one gigabyte (GB), and doesn't require serialization. Then, multiple nodes can produce output in parallel. Don't use this flag when query results are small, since it might needlessly generate many small data shards.
• Data ingestion is a resource-intensive operation that might affect concurrent activities on the database, including running queries. Avoid running too many ingestion commands at the same time.
• Limit the data for ingestion to less than one GB per ingestion operation. If necessary, use multiple ingestion commands.

Supported ingestion properties

Property	Type	Description
distributed	bool	If true, the command ingests from all nodes executing the query in parallel. Default is false. See performance tips.
creationTime	string	The datetime value, formatted as an ISO8601 string, to use at the creation time of the ingested data extents. If unspecified, now() is used. When specified, make sure the Lookback property in the target table's effective Extents merge policy is aligned with the specified value.
extend_schema	bool	If true, the command might extend the schema of the table. Default is false. This option applies only to .append, .set-or-append, and set-or-replace commands. This option requires at least Table Admin permissions.
recreate_schema	bool	If true, the command might recreate the schema of the table. Default is false. This option applies only to the .set-or-replace command. This option takes precedence over the extend_schema property if both are set. This option requires at least Table Admin permissions.
folder	string	The folder to assign to the table. If the table already exists, this property overwrites the table's folder.
ingestIfNotExists	string	If specified, ingestion fails if the table already has data tagged with an ingest-by: tag with the same value. For more information, see ingest-by: tags.
policy_ingestiontime	bool	If true, the Ingestion Time Policy is enabled on the table. The default is true.
tags	string	A JSON string that represents a list of tags to associate with the created extent.
docstring	string	A description used to document the table.
persistDetails	A Boolean value that, if specified, indicates that the command should persist the detailed results for retrieval by the .show operation details command. Defaults to false.	with (persistDetails=true)

Schema considerations

• .set-or-replace preserves the schema unless one of extend_schema or recreate_schema ingestion properties is set to true.
• .set-or-append and .append commands preserve the schema unless the extend_schema ingestion property is set to true.
• Matching the result set schema to that of the target table is based on the column types. There's no matching of column names. Make sure that the query result schema columns are in the same order as the table, otherwise data is ingested into the wrong columns.

Caution

If the schema is modified, it happens in a separate transaction before the actual data ingestion. This means the schema might be modified even when there is a failure to ingest the data.

Character limitation

The command fails if the query generates an entity name with the $ character. The entity names must comply with the naming rules, so the $ character must be removed for the ingest command to succeed.

For example, in the following query, the search operator generates a column $table. To store the query results, use project-rename to rename the column.

.set Texas <| search State has 'Texas' | project-rename tableName=$table

Returns

Returns information on the extents created because of the .set or .append command.

Examples

Create and update table from query source

The following query creates the RecentErrors table with the same schema as LogsTable. It updates RecentErrors with all error logs from LogsTable over the last hour.

.set RecentErrors <|
   LogsTable
   | where Level == "Error" and Timestamp > now() - time(1h)

Create and update table from query source using the distributed flag

The following example creates a new table called OldExtents in the database, asynchronously. The dataset is expected to be bigger than one GB (more than ~one million rows) so the distributed flag is used. It updates OldExtents with ExtentId entries from the MyExtents table that were created more than 30 days ago.

.set async OldExtents with(distributed=true) <|
   MyExtents 
   | where CreatedOn < now() - time(30d)
   | project ExtentId

Append data to table

The following example filters ExtentId entries in the MyExtents table that were created more than 30 days ago and appends the entries to the OldExtents table with associated tags.

.append OldExtents with(tags='["TagA","TagB"]') <| 
   MyExtents 
   | where CreatedOn < now() - time(30d) 
   | project ExtentId

Create or append a table with possibly existing tagged data

The following example either appends to or creates the OldExtents table asynchronously. It filters ExtentId entries in the MyExtents table that were created more than 30 days ago and specifies the tags to append to the new extents with ingest-by:myTag. The ingestIfNotExists parameter ensures that the ingestion only occurs if the data doesn't already exist in the table with the specified tag.

.set-or-append async OldExtents with(tags='["ingest-by:myTag"]', ingestIfNotExists='["myTag"]') <|
   MyExtents
   | where CreatedOn < now() - time(30d)
   | project ExtentId

Create table or replace data with associated data

The following query replaces the data in the OldExtents table, or creates the table if it doesn't already exist, with ExtentId entries in the MyExtents table that were created more than 30 days ago. Tag the new extent with ingest-by:myTag if the data doesn't already exist in the table with the specified tag.

.set-or-replace async OldExtents with(tags='["ingest-by:myTag"]', ingestIfNotExists='["myTag"]') <| 
   MyExtents 
   | where CreatedOn < now() - time(30d) 
   | project ExtentId

Append data with associated data

The following example appends data to the OldExtents table asynchronously, using ExtentId entries from the MyExtents table that were created more than 30 days ago. It sets a specific creation time for the new extents.

.append async OldExtents with(creationTime='2017-02-13T11:09:36.7992775Z') <| 
   MyExtents 
   | where CreatedOn < now() - time(30d) 
   | project ExtentId     

Sample output

The following is a sample of the type of output you may see from your queries.

ExtentId	OriginalSize	ExtentSize	CompressedSize	IndexSize	RowCount
23a05ed6-376d-4119-b1fc-6493bcb05563	1291	5882	1568	4314	10

Related content

• Data formats supported for ingestion
• Inline ingestion
• Ingest from storage