ALTER PARTITION FUNCTION (Transact-SQL) Alters a partition
function by splitting or merging its boundary values. By
executing ALTER PARTITION FUNCTION, one partition of any table
or index that uses the partition function can be split into two
partitions, or two partitions can be merged into one less
partition. More than one table or index can use the same
partition function. ALTER PARTITION FUNCTION affects all of them
in a single transaction. Always keep empty partitions at both
ends of the partition range to guarantee that the partition
split (before loading new data) and partition merge (after
unloading old data) do not incur any data movement. Avoid
splitting or merging populated partitions. This can be extremely
inefficient, as this may cause as much as four times more log
generation, and may also cause severe locking. ALTER PARTITION
FUNCTION repartitions any tables and indexes that use the
function in a single atomic operation. However, this operation
occurs offline, and depending on the extent of repa