Identity columns near limit

If your application relies on identity columns, use this metric to measure the number of identity columns that are near to the limit per database.

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If your application relies on identity columns, use this metric to measure the number of identity columns that are near to the limit per database. If an identity column is getting close to the limit of the datatype, you need to know so that you can avoid logical problems in your application and SQL Server errors. For example, if you created an IDENTITY column of smallint datatype, if you try to insert more than 32767 rows in the table, you will get the following error:

Server: Msg 8115, Level 16, State 1, Line 1

Arithmetic overflow error converting IDENTITY to data type smallint. Arithmetic overflow occurred.

This is a limitation of the datatype, not the identity.

For more information, see http://vyaskn.tripod.com/sql_server_check_identity_columns.htm

If you want to carry out further analysis, run this query to find which tables have the identity column near to the limit:
[sql]WITH CTE_1
AS
(
SELECT OBJECT_NAME(a.Object_id) as table_name,
a.Name as columnname,
CONVERT(bigint, ISNULL(a.last_value,0)) AS last_value,
Case
When b.name = ‘tinyint’ Then 255
When b.name = ‘smallint’ Then 32767
When b.name = ‘int’ Then 2147483647
When b.name = ‘bigint’ Then 9223372036854775807
End As dt_value
FROM sys.identity_columns a
INNER JOIN sys.types As b
ON a.system_type_id = b.system_type_id
),
CTE_2
AS
(
SELECT *,
CONVERT(Numeric(18,2), ((CONVERT(Float, last_value) / CONVERT(Float, dt_value)) * 100)) AS "Percent"
FROM CTE_1
)
SELECT *
FROM CTE_2
ORDER BY "Percent" DESC; [/sql]

Identity columns near limit, 4.5 out of 5 based on 6 ratings

Metric definition

Name

Identity columns near limit

Description

This metric measures the number of identity columns that are near to the limit per database. If an identity column is getting close to the limit of the datatype, you need to know so that you can avoid logical problems in your application and SQL Server errors. For example, if you created an IDENTITY column of smallint datatype, if you try to insert more than 32767 rows in the table, you will get the following error:

Server: Msg 8115, Level 16, State 1, Line 1

Arithmetic overflow error converting IDENTITY to data type smallint. Arithmetic overflow occurred.

This is a limitation of the datatype, not the identity.

For more information, see http://vyaskn.tripod.com/sql_server_check_identity_columns.htm

If you want to carry out further analysis, run this query to find which tables have the identity column near to the limit:

WITH  CTE_1
        AS (SELECT OBJECT_NAME(a.Object_id) AS table_name,
                a.Name AS columnname,
                CONVERT(BIGINT, ISNULL(a.last_value, 0)) AS last_value,
                CASE WHEN b.name = 'tinyint' THEN 255
                     WHEN b.name = 'smallint' THEN 32767
                     WHEN b.name = 'int' THEN 2147483647
                     WHEN b.name = 'bigint' THEN 9223372036854775807
                END AS dt_value
              FROM sys.identity_columns a 
              INNER JOIN sys.types AS b
              ON
                a.system_type_id = b.system_type_id
           ),
      CTE_2
        AS (SELECT *,
                CONVERT(NUMERIC(18, 2), ((CONVERT(FLOAT, last_value)
                / CONVERT(FLOAT, dt_value)) * 100)) AS "Percent"
              FROM CTE_1
           )
  SELECT *
    FROM CTE_2
    ORDER BY "Percent" DESC;

The T-SQL query that will collect data

Instances to collect from

Select all

Databases to collect from

1

Collection frequency

86400

Use collected or calculated values

Leave the Use a calculated rate of change between collections check box unchecked

Metric collection

Enabled

Alert definition

Alert name

Identity columns near limit

Description

This alert is raised if an identity column is getting close to the limit of the datatype. You need to know about this so you can avoid logical problems in your application and SQL Server errors. For example, if you created an IDENTITY column of smallint datatype, if you try to insert more than 32767 rows in the table, you will get the following error:

Server: Msg 8115, Level 16, State 1, Line 1

Arithmetic overflow error converting IDENTITY to data type smallint. Arithmetic overflow occurred.

This is a limitation of the datatype, not the identity.

For more information, see http://vyaskn.tripod.com/sql_server_check_identity_columns.htm

If you want to carry out further analysis, run this query to find which tables have the identity column near to the limit:

WITH  CTE_1
        AS (SELECT OBJECT_NAME(a.Object_id) AS table_name,
                a.Name AS columnname,
                CONVERT(BIGINT, ISNULL(a.last_value, 0)) AS last_value,
                CASE WHEN b.name = 'tinyint' THEN 255
                     WHEN b.name = 'smallint' THEN 32767
                     WHEN b.name = 'int' THEN 2147483647
                     WHEN b.name = 'bigint' THEN 9223372036854775807
                END AS dt_value
              FROM sys.identity_columns a 
              INNER JOIN sys.types AS b
              ON
                a.system_type_id = b.system_type_id
           ),
      CTE_2
        AS (SELECT *,
                CONVERT(NUMERIC(18, 2), ((CONVERT(FLOAT, last_value)
                / CONVERT(FLOAT, dt_value)) * 100)) AS "Percent"
              FROM CTE_1
           )
  SELECT *
    FROM CTE_2
    ORDER BY "Percent" DESC;

Raise an alert when the metric value goes

Above the defined threshholds

Default threshold values

High:10
Medium:5
Low:0

Note: These thresholds are intended as guideline values. If they seem too high or too low in your environment, replace them with values more suited to your server performance.

Raise an alert when the threshold is passed for

1 collection

Alert is

Enabled