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How easy is it to find IDENTITY columns at risk of overflow?

My database is aging and one of my largest columns INT IDENTITYhas a value of around 1.3 billion. This will exceed about 2.1 billion. I plan to increase its size, but I do not want to do this too early due to the number of records in the database. I can replace my database equipment before increasing the size of the column, which can compensate for any performance issues that may arise. I also want to keep track of all the other columns in my databases that are more than 50% full. These are many tables, and manually checking each of them is not practical.

This is how I get the value now (I know that the return value may be a bit outdated, but it is good enough for my purposes):

PRINT IDENT_CURRENT('MyDatabase.dbo.MyTable')

Can I use INFORMATION_SCHEMAto get this information?

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4 answers

You can view the system catalog view sys.identity_columns:

SELECT     
    name,
    seed_value, increment_value, last_value
FROM sys.identity_columns

This gives you the name, seed, increment, and last value for each column. The view also contains a data type, so you can easily figure out which identifier columns might end in a number soon ...

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. INFORMATION_SCHEMA IDENTITY, IDENT_CURRENT DATA_TYPE . , .

EXEC master.dbo.CheckIdentityColumns 'MyDatabase' --all

EXEC master.dbo.CheckIdentityColumns 'MyDatabase', 50 --columns 50% full or greater

EXEC master.dbo.CheckIdentityColumns 'MyDatabase', 50, 'int' --only int columns

:

Table                     Column             Type    Percent Full Remaining
------------------------- ------------------ ------- ------------ ---------------
MyDatabase.dbo.Table1     Table1ID           int     9            1,937,868,393
MyDatabase.dbo.Table2     Table2ID           int     5            2,019,944,894
MyDatabase.dbo.Table3     Table3ID           int     9            1,943,793,775

, , .

IDENTITY tracking spreadsheet

CheckIdentityColumns

USE master
GO

CREATE PROCEDURE dbo.CheckIdentityColumns
    (
    @Database       AS NVARCHAR(128),
    @PercentFull    AS TINYINT          = 0,
    @Type           AS VARCHAR(8)       = NULL
    )

AS

--this procedure assumes you are not using negative numbers in your identity columns

DECLARE @Sql NVARCHAR(3000)

SET @Sql = 
'USE ' + @Database + '

SELECT                        
    [Column].TABLE_CATALOG + ''.'' +
    [Column].TABLE_SCHEMA + ''.'' +
    [Table].TABLE_NAME          AS [Table],
    [Column].COLUMN_NAME                        AS [Column],
    [Column].DATA_TYPE              AS [Type],
    CAST((
    CASE LOWER([Column].DATA_TYPE)
    WHEN ''tinyint''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 255)  
    WHEN ''smallint''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 32767)  
    WHEN ''int''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 2147483647)  
    WHEN ''bigint''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 9223372036854775807)  
    WHEN ''decimal''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / (([Column].NUMERIC_PRECISION * 10) - 1))  
    END * 100) AS INT)                  AS [Percent Full],
    REPLACE(CONVERT(VARCHAR(19), CAST(
    CASE LOWER([Column].DATA_TYPE)
    WHEN ''tinyint''
    THEN (255 - IDENT_CURRENT([Table].TABLE_NAME))  
    WHEN ''smallint''
    THEN (32767 - IDENT_CURRENT([Table].TABLE_NAME))  
    WHEN ''int''
    THEN (2147483647 - IDENT_CURRENT([Table].TABLE_NAME))  
    WHEN ''bigint''
    THEN (9223372036854775807 - IDENT_CURRENT([Table].TABLE_NAME))  
    WHEN ''decimal''
    THEN ((([Column].NUMERIC_PRECISION * 10) - 1) - IDENT_CURRENT([Table].TABLE_NAME))  
    END
    AS MONEY) , 1), ''.00'', '''')              AS Remaining


FROM                       
    INFORMATION_SCHEMA.COLUMNS                  AS [Column]

    INNER JOIN    
    INFORMATION_SCHEMA.TABLES                   AS [Table]
    ON      [Table].TABLE_NAME                  = [Column].TABLE_NAME

WHERE
    COLUMNPROPERTY(
        OBJECT_ID([Column].TABLE_NAME), 
        [Column].COLUMN_NAME, ''IsIdentity'') = 1 --true
    AND [Table].TABLE_TYPE                      = ''Base Table'' 
    AND [Table].TABLE_NAME                      NOT LIKE ''dt%'' 
    AND [Table].TABLE_NAME                      NOT LIKE ''MS%'' 
    AND [Table].TABLE_NAME                      NOT LIKE ''syncobj_%''
    AND CAST(
    (
    CASE LOWER([Column].DATA_TYPE)
    WHEN ''tinyint''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 255)  
    WHEN ''smallint''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 32767)  
    WHEN ''int''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 2147483647)  
    WHEN ''bigint''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / 9223372036854775807)  
    WHEN ''decimal''
    THEN (IDENT_CURRENT([Table].TABLE_NAME) / (([Column].NUMERIC_PRECISION * 10) - 1))  
    END * 100
    ) AS INT)                                    >= ' + CAST(@PercentFull AS VARCHAR(4))

IF (@Type IS NOT NULL) 
    SET @Sql = @Sql + 'AND  LOWER([Column].DATA_TYPE)    = ''' + LOWER(@Type) + ''''

SET @Sql = @Sql + '

ORDER BY
    [Column].TABLE_CATALOG + ''.'' +
    [Column].TABLE_SCHEMA + ''.'' +
    [Table].TABLE_NAME,
    [Column].COLUMN_NAME'

EXECUTE sp_executesql @Sql
GO
+5

Keith Walton , . , , :

SELECT sys.tables.name AS [Table Name], 
    last_value AS [Last Value],     
    MAX_LENGTH,
    CAST(cast(last_value as int) / 2147483647.0 * 100.0 AS DECIMAL(5,2)) 
        AS [Percentage of ID Used], 
    2147483647 - cast(last_value as int) AS Remaining
FROM sys.identity_columns
    INNER JOIN sys.tables
        ON sys.identity_columns.object_id = sys.tables.object_id
ORDER BY last_value DESC

:

Table Name      Last Value      MAX_LENGTH  Percentage of ID Used   Remaining
My_Table        49181800             4               2.29             2098301847

+2

When developing a solution for this problem, we found this thread both informative and interesting (we also wrote a detailed post about this and described how our tool works.)

In our solution, we request information_schemato get a list of all the columns. Then we wrote a program that will go through each of them and calculate the maximum and minimum (we take into account both overflow and underutilization).

SELECT
    b.COLUMN_NAME,
    b.COLUMN_TYPE,
    b.DATA_TYPE,
    b.signed,
    a.TABLE_NAME,
    a.TABLE_SCHEMA
FROM (
    -- get all tables
    SELECT
    TABLE_NAME, TABLE_SCHEMA
    FROM information_schema.tables
    WHERE 
    TABLE_TYPE IN ('BASE TABLE', 'VIEW') AND
    TABLE_SCHEMA NOT IN ('mysql', 'performance_schema')
) a
JOIN (
    -- get information about columns types
    SELECT
    TABLE_NAME,
    COLUMN_NAME,
    COLUMN_TYPE,
    TABLE_SCHEMA,
    DATA_TYPE,
    (!(LOWER(COLUMN_TYPE) REGEXP '.*unsigned.*')) AS signed
    FROM information_schema.columns
) b ON a.TABLE_NAME = b.TABLE_NAME AND a.TABLE_SCHEMA = b.TABLE_SCHEMA
ORDER BY a.TABLE_SCHEMA DESC;
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