Calculating total “on row” bytes for each row … the easy way
We want to calculate the total "on row" storage bytes for each row in the table. As we understand it, we must add up the DATALENGTH() of each column while also accounting for NULLs and things like VARCHAR(MAX) which only have a 24-byte pointer "on row". We are aware there is also some overhead for each row which is not accounted for in the query below.
SELECT ROW_ID,
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL1','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL1), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL2','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL2), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL3','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL3), 1)
END
+
...
...
AS ROW_SIZE
FROM EXAMPLE_TABLE
ORDER BY ROW_SIZE DESC
;
What a beast! And it's only an approximation.
Then we discovered
DBCC SHOWCONTIG ('EXAMPLE_TABLE') WITH TABLERESULTS
which returns MaximumRecordSize. This reveals that there is already an algorithm buried somewhere within SQL Server which is capable of calculating the exact size of a row.
How can we access that algorithm directly?
sql-server sql-server-2017 storage dbcc size
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
add a comment |
We want to calculate the total "on row" storage bytes for each row in the table. As we understand it, we must add up the DATALENGTH() of each column while also accounting for NULLs and things like VARCHAR(MAX) which only have a 24-byte pointer "on row". We are aware there is also some overhead for each row which is not accounted for in the query below.
SELECT ROW_ID,
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL1','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL1), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL2','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL2), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL3','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL3), 1)
END
+
...
...
AS ROW_SIZE
FROM EXAMPLE_TABLE
ORDER BY ROW_SIZE DESC
;
What a beast! And it's only an approximation.
Then we discovered
DBCC SHOWCONTIG ('EXAMPLE_TABLE') WITH TABLERESULTS
which returns MaximumRecordSize. This reveals that there is already an algorithm buried somewhere within SQL Server which is capable of calculating the exact size of a row.
How can we access that algorithm directly?
sql-server sql-server-2017 storage dbcc size
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
3
sys.dm_db_index_physical_stats is probably better to try working off of, especially since that DBCC command is deprecated.
– LowlyDBA
9 hours ago
add a comment |
We want to calculate the total "on row" storage bytes for each row in the table. As we understand it, we must add up the DATALENGTH() of each column while also accounting for NULLs and things like VARCHAR(MAX) which only have a 24-byte pointer "on row". We are aware there is also some overhead for each row which is not accounted for in the query below.
SELECT ROW_ID,
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL1','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL1), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL2','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL2), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL3','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL3), 1)
END
+
...
...
AS ROW_SIZE
FROM EXAMPLE_TABLE
ORDER BY ROW_SIZE DESC
;
What a beast! And it's only an approximation.
Then we discovered
DBCC SHOWCONTIG ('EXAMPLE_TABLE') WITH TABLERESULTS
which returns MaximumRecordSize. This reveals that there is already an algorithm buried somewhere within SQL Server which is capable of calculating the exact size of a row.
How can we access that algorithm directly?
sql-server sql-server-2017 storage dbcc size
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
We want to calculate the total "on row" storage bytes for each row in the table. As we understand it, we must add up the DATALENGTH() of each column while also accounting for NULLs and things like VARCHAR(MAX) which only have a 24-byte pointer "on row". We are aware there is also some overhead for each row which is not accounted for in the query below.
SELECT ROW_ID,
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL1','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL1), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL2','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL2), 1)
END
+
CASE
WHEN COLUMNPROPERTY(OBJECT_ID('EXAMPLE_TABLE'),'COL3','PRECISION') = -1 THEN 24
ELSE ISNULL(DATALENGTH(COL3), 1)
END
+
...
...
AS ROW_SIZE
FROM EXAMPLE_TABLE
ORDER BY ROW_SIZE DESC
;
What a beast! And it's only an approximation.
Then we discovered
DBCC SHOWCONTIG ('EXAMPLE_TABLE') WITH TABLERESULTS
which returns MaximumRecordSize. This reveals that there is already an algorithm buried somewhere within SQL Server which is capable of calculating the exact size of a row.
How can we access that algorithm directly?
sql-server sql-server-2017 storage dbcc size
sql-server sql-server-2017 storage dbcc size
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
asked 9 hours ago
UnLogicGuysUnLogicGuys
16718
16718
3
sys.dm_db_index_physical_stats is probably better to try working off of, especially since that DBCC command is deprecated.
– LowlyDBA
9 hours ago
add a comment |
3
sys.dm_db_index_physical_stats is probably better to try working off of, especially since that DBCC command is deprecated.
– LowlyDBA
9 hours ago
3
3
sys.dm_db_index_physical_stats is probably better to try working off of, especially since that DBCC command is deprecated.
– LowlyDBA
9 hours ago
sys.dm_db_index_physical_stats is probably better to try working off of, especially since that DBCC command is deprecated.
– LowlyDBA
9 hours ago
add a comment |
1 Answer
1
active
oldest
votes
How can we access that algorithm directly?
In so far as the answer to this question, specifically, you can't access it directly. There is nothing where you can say SELECT GetMeMaxRowSize(MyTable, MyPartition, MyIndex).
However, as LowlyDBA has pointed out, you can use sys.dm_db_index_physical_stats to give you more information than ShowContig. The quite interesting thing is that if you run DBCC SHOWCONTIG(), capturing deprecated information, you should see a message to use the aforementioned DMV in place of the ShowContig command.
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
That's neat! Any idea if we'll see more explicit nudging around deprecated features, like said message, going forwards?
– LowlyDBA
8 hours ago
@LowlyDBA Unfortunately I do not, but we try to point people in the right direction :) If you think this should be updated or put anywhere in Docs, please let me know.
– Sean Gallardy
8 hours ago
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
How can we access that algorithm directly?
In so far as the answer to this question, specifically, you can't access it directly. There is nothing where you can say SELECT GetMeMaxRowSize(MyTable, MyPartition, MyIndex).
However, as LowlyDBA has pointed out, you can use sys.dm_db_index_physical_stats to give you more information than ShowContig. The quite interesting thing is that if you run DBCC SHOWCONTIG(), capturing deprecated information, you should see a message to use the aforementioned DMV in place of the ShowContig command.
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
That's neat! Any idea if we'll see more explicit nudging around deprecated features, like said message, going forwards?
– LowlyDBA
8 hours ago
@LowlyDBA Unfortunately I do not, but we try to point people in the right direction :) If you think this should be updated or put anywhere in Docs, please let me know.
– Sean Gallardy
8 hours ago
add a comment |
How can we access that algorithm directly?
In so far as the answer to this question, specifically, you can't access it directly. There is nothing where you can say SELECT GetMeMaxRowSize(MyTable, MyPartition, MyIndex).
However, as LowlyDBA has pointed out, you can use sys.dm_db_index_physical_stats to give you more information than ShowContig. The quite interesting thing is that if you run DBCC SHOWCONTIG(), capturing deprecated information, you should see a message to use the aforementioned DMV in place of the ShowContig command.
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
That's neat! Any idea if we'll see more explicit nudging around deprecated features, like said message, going forwards?
– LowlyDBA
8 hours ago
@LowlyDBA Unfortunately I do not, but we try to point people in the right direction :) If you think this should be updated or put anywhere in Docs, please let me know.
– Sean Gallardy
8 hours ago
add a comment |
How can we access that algorithm directly?
In so far as the answer to this question, specifically, you can't access it directly. There is nothing where you can say SELECT GetMeMaxRowSize(MyTable, MyPartition, MyIndex).
However, as LowlyDBA has pointed out, you can use sys.dm_db_index_physical_stats to give you more information than ShowContig. The quite interesting thing is that if you run DBCC SHOWCONTIG(), capturing deprecated information, you should see a message to use the aforementioned DMV in place of the ShowContig command.
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
How can we access that algorithm directly?
In so far as the answer to this question, specifically, you can't access it directly. There is nothing where you can say SELECT GetMeMaxRowSize(MyTable, MyPartition, MyIndex).
However, as LowlyDBA has pointed out, you can use sys.dm_db_index_physical_stats to give you more information than ShowContig. The quite interesting thing is that if you run DBCC SHOWCONTIG(), capturing deprecated information, you should see a message to use the aforementioned DMV in place of the ShowContig command.
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
answered 8 hours ago
Sean GallardySean Gallardy
16.2k22649
16.2k22649
That's neat! Any idea if we'll see more explicit nudging around deprecated features, like said message, going forwards?
– LowlyDBA
8 hours ago
@LowlyDBA Unfortunately I do not, but we try to point people in the right direction :) If you think this should be updated or put anywhere in Docs, please let me know.
– Sean Gallardy
8 hours ago
add a comment |
That's neat! Any idea if we'll see more explicit nudging around deprecated features, like said message, going forwards?
– LowlyDBA
8 hours ago
@LowlyDBA Unfortunately I do not, but we try to point people in the right direction :) If you think this should be updated or put anywhere in Docs, please let me know.
– Sean Gallardy
8 hours ago
That's neat! Any idea if we'll see more explicit nudging around deprecated features, like said message, going forwards?
– LowlyDBA
8 hours ago
That's neat! Any idea if we'll see more explicit nudging around deprecated features, like said message, going forwards?
– LowlyDBA
8 hours ago
@LowlyDBA Unfortunately I do not, but we try to point people in the right direction :) If you think this should be updated or put anywhere in Docs, please let me know.
– Sean Gallardy
8 hours ago
@LowlyDBA Unfortunately I do not, but we try to point people in the right direction :) If you think this should be updated or put anywhere in Docs, please let me know.
– Sean Gallardy
8 hours ago
add a comment |
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3
sys.dm_db_index_physical_stats is probably better to try working off of, especially since that DBCC command is deprecated.
– LowlyDBA
9 hours ago