Sql-server – How to move a Daily Partition to a Monthly Partitioned Table

Here are two best practices for partitioning that pertain to the question:

1. Keep an empty staging partition at the leftmost and rightmost ends of the partition range to ensure that the partitions split when loading in new data, and merge, after unloading old data, do not cause data movement.
2. Do not split or merge a partition already populated with data because this can cause severe locking and explosive log growth.

http://www.informit.com/articles/article.aspx?p=1946159&seqNum=5

If the leftmost end of your partition is empty, use ALTER PARTITION FUNCTION SPLIT RANGE to add new ranges to the partition function.

To check if the leftmost partition is empty, use a query like the following:

DECLARE @PartitionFunctionName sysname = 'YourPartitionFunctionNameHere';

SELECT 
p.partition_number, SUM(pst.row_count) RowCountInPartition, pf.name PartitionFunction, ps.name PartitionScheme
FROM sys.dm_db_partition_stats pst
INNER JOIN sys.partitions p ON pst.partition_id = p.partition_id
INNER JOIN sys.indexes i ON p.object_id = i.object_id AND p.index_id = i.index_id
INNER JOIN sys.partition_schemes ps ON ps.data_space_id = i.data_space_id
INNER JOIN sys.partition_functions pf ON ps.function_id = pf.function_id
WHERE pf.name = @PartitionFunctionName
GROUP BY p.partition_number, pf.name, ps.name;

If the first partition is not empty, the best practices recommend that you create a new function with all values, create a new table on that function, then insert the data to the new table.

Also, if the left partition just has a few records, a split may be fine. Not sure on that as I've never tried it.

Whatever you do, make sure to leave some empty partitions at the leftmost and rightmost partition when you're finished. I might even go so far as to creating partition ranges for 0 and 1, then add a check constraint to prevent the first partition from getting data in it. Do the same thing for the end.

When you are working with partition switching, SQL Server will need to verify that the source table/partition boundaries can fit in the destination table/partition boundaries. In other words, you're trying to switch data from dbo.temp_table to dbo.play_table's partition 2. Think of it like this, the data for the c1 in dbo.temp_table is constrained only by the data type (int), so you can have values ranging from -2,147,483,648 to 2,147,483,647. But conversely, you're destination (dbo.play_table partition 2) has a range from 4 to 2,147,483,647.

Your data does not violate this, but it is the metadata that can't allow this. You could just as easily insert the value -10 into dbo.temp_table. The partition switching would fail the same way and make more sense, as -10 does not fit in dbo.play_table's 2nd partition boundaries.

If you wanted to make this code work, you'd need to explicitly tell SQL Server that dbo.temp_table will never have any data that won't fit in dbo.play_table's 2nd partition. You could do this with a check constraint:

/******************************************************************************
    your code omitted for brevity
******************************************************************************/

-- move contents of play_table to temp_table, which is not partitioned
-- but is in the same filegroup
ALTER TABLE dbo.play_table
    SWITCH PARTITION 2 TO temp_table;
PRINT 'Switched from partitioned table to non-partitioned table';

/******************************************************************************
    added check constraint so that data can fit in the destination partition
******************************************************************************/
alter table dbo.temp_table
add constraint CK_TempTable_C1 check (c1 >= 4);
go
/******************************************************************************
    end of added code
******************************************************************************/

-- move data back to partitioned play_table from unpartitioned temp_table
-- this will no longer FAIL
ALTER TABLE dbo.temp_table
    SWITCH TO play_table partition 2;
PRINT 'Switched from non-partitioned table to partitioned table';

/******************************************************************************
    your code omitted for brevity
******************************************************************************/

That above sample addition to your code makes this a working solution. Now SQL Server knows that the data in dbo.temp_table can fit in partition 2 of dbo.play_table because of the added check constraint to dbo.temp_table.