I am struggling to find the reason of the arithmetic overflow. why is it happening?
Most likely the metadata is returning some unexpected values that your code cannot handle. For example:
-- Example values returned from sysfiles and FILEPROPERTY
DECLARE
@size integer = 1,
@spaceused integer = 10000;
-- The essence of the code in the question
SELECT
CAST
(
100 *
(
CAST
(
(
(@size/128.0 - @spaceused/128.0)/(@size/128.0)
)
AS decimal(5,2)
)
)
AS varchar(8)
) + '' AS FreeSpacePct;
...returns the error mentioned in the question, because the computed (negative!) value will not fit in decimal(5,2)
.
There are reasons why size might be reported as much lower than space used, including tempdb file growths, filestream files, bugs in older versions of SQL Server...too many to list. You could/should code defensively against this possibility (and also for offline/defunct files...and so on).
The question is tagged SQL Server 2014, so there's no need to use the deprecated sys.sysfiles
view (for backward compatibility with SQL Server 2000):
I might write this query as:
SELECT
DatabaseName = DB_NAME(),
[FileName] = DF.name,
FileType = DF.type_desc,
SizeMB = STR(DF.size * Factor.PagesToMB, 10, 2),
SpaceUsedMB = STR(FP.SpaceUsed * Factor.PagesToMB, 10, 2),
FreeSpaceMB = STR(FS.FreeSpace * Factor.PagesToMB, 10, 2),
FreeSpacePct = STR(Factor.ToPct * FS.FreeSpace / DF.size, 7, 4)
FROM sys.database_files AS DF
CROSS APPLY (SELECT FILEPROPERTY(DF.name, 'SpaceUsed')) AS FP (SpaceUsed)
CROSS APPLY (SELECT DF.size - FP.SpaceUsed) AS FS (FreeSpace)
CROSS JOIN (SELECT 8e0 / 1024e0, 1e2) AS Factor (PagesToMB, ToPct);
Main advantages:
A dynamic SQL version (to collect information for all databases):
DECLARE @SQL nvarchar(2000);
SET @SQL = N'
USE ?;
SELECT
DatabaseName = DB_NAME(),
[FileName] = DF.name,
FileType = DF.type_desc,
SizeMB = STR(DF.size * Factor.PagesToMB, 10, 2),
SpaceUsedMB = STR(FP.SpaceUsed * Factor.PagesToMB, 10, 2),
FreeSpaceMB = STR(FS.FreeSpace * Factor.PagesToMB, 10, 2),
FreeSpacePct = STR(Factor.ToPct * FS.FreeSpace / DF.size, 7, 4)
FROM sys.database_files AS DF
CROSS APPLY (SELECT FILEPROPERTY(DF.name, ''SpaceUsed'')) AS FP (SpaceUsed)
CROSS APPLY (SELECT DF.size - FP.SpaceUsed) AS FS (FreeSpace)
CROSS JOIN (SELECT 8e0 / 1024e0, 1e2) AS Factor (PagesToMB, ToPct);
';
DECLARE @Results AS table
(
DatabaseName sysname NOT NULL,
[FileName] sysname NOT NULL,
FileType nvarchar(60) NOT NULL,
SizeMB char(10) NULL,
SpaceUsedMB char(10) NULL,
FreeSpaceMB char(10) NULL,
FreeSpacePct char(7) NULL
);
INSERT @Results
EXECUTE sys.sp_MSforeachdb
@command1 = @SQL;
SELECT R.*
FROM @Results AS R
ORDER BY R.DatabaseName; -- Or whatever
Usual caveats about using sp_MSforeachdb
.
Best Answer
There was an issue with the latest release, shown in ISSUE 526. It was updated, by changing this code on line 472.
FROM
TO
If you do a new Pull request through github it has the fix in it.