.show table data statistics command

Artikkeli
08/12/2024

Applies to: ✅ Microsoft Fabric ✅ Azure Data Explorer

Displays the table data statistics estimation by table column.

Note

This command only returns statistics for data stored in columnar stores. Row store data statistics are not returned.

Permissions

You must have at least Database User, Database Viewer, or Database Monitor permissions to run this command. For more information, see role-based access control.

Syntax

.show table TableName data statistics [ with ( PropertyName = PropertyValue [, ...]) ]

Learn more about syntax conventions.

Parameters

Name	Type	Required	Description
TableName	`string`	✔️	The name of the table for which to show statistics.
PropertyName, PropertyValue	`string`		A comma-separated list of optional Supported properties.

Supported properties

The following properties can be specified. All properties are optional.

Property name	Description	Property values
`samplepercent`	Scans the specified percentage of data.	Integer between 0 and 100
`scope`	Defines if only the hot cache is scanned or if the whole data is scanned.	Specify `"hotcache"` to only scan hot cache data, or `"all"` to scan all the data.
`from`	Scans data extents created after this time.	`datetime`
`to`	Scan data extents created before this time.	`datetime`

If no options are provided, only 1% of hot cache data is scanned.

Returns

The command returns a result table that contains the following information.

Column Name	Type	Description
`ColumnName`	`string`	Table column name.
`ColumnType`	`string`	Table column data type.
`ColumnId`	`guid`	Table column internal ID.
`OriginalSize`	`long`	Estimation of ingested data size in bytes.
`ExtentSize`	`long`	Estimation of total size of extents (data size + index size) in bytes.
`CompressionRatio`	`real`	Ratio of original data size to extent data size.
`DataCompressedSize`	`long`	Extents data size in bytes, excluding indexes.
`SharedIndexSize`	`long`	Text index size in bytes. The text index is shared by all table columns.
`IndexSize`	`long`	Size of numeric indexes in bytes.
`IndexSizePercent`	`real`	Ratio of the index size to original data size in bytes.
`StorageEngineVersion`	`string`	Engine version. If data exists for multiple engine versions, the output includes an entry for each version.
`PresentRowCount`	`long`	Total rows count, excluding deleted rows.
`DeletedRowCount`	`long`	Deleted rows count.
`SamplePercent`	`real`	Actual data sampling percentage, which may differ from the hint provided in `samplepercent` option.
`IncludeColdData`	`bool`	Whether cold data was taken into account when calculating statistics estimate.

Note

ExtentSize doesn't include shared text index size. There are two ways to calculate total table data size:

Sum all ExtentSize values and add the SharedIndexSize value.
Run the .show table details command, and use the TotalExtentSize value.

Example

.show table Users data statistics with (scope="all", samplepercent=80)

Output

ColumnName	ColumnType	ColumnId	OriginalSize	ExtentSize	CompressionRatio	DataCompressedSize	SharedIndexSize	IndexSize	IndexSizePercent	StorageEngineVersion	PresentRowCount	SamplePercent	IncludeColdData
Name	string	45c15cfe-ef38-4153-97e7-c18d21651fc2	60907	137305	0.44	137305	27787	0	0	V3	2500	80	True
Usage	real	c0aa6668-0f73-46a1-874e-f1b19123eb61	20000	20282	0.99	20102	27787	180	0.9	V3	2500	80	True
ID	long	eb01bab7-da60-4515-a5d4-4780a827bd85	20000	5722	3.49	5152	27787	570	2.85	V3	2500	80	True

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