Round-robin |
The database server automatically balances data
over time. |
The database server cannot eliminate fragments. |
You cannot determine if the integrity of the transaction
is compromised when you use the dataskip feature. You can insert
rows into a table that is fragmented by round-robin if any table fragment
is accessible, even though some fragments are not available. |
Expression-based |
You must know the data distribution to balance the
number of rows in fragments. |
If
expressions on one or two columns are used, the database server
can eliminate fragments for queries that have either range or equality expressions. |
You can determine whether the integrity of a transaction
has been compromised when you use the dataskip feature. You cannot
insert rows if the fragment for those rows is not available. |
Hash |
The database server does not necessarily balance
data over time. If the fragmentation column contains unique, well
distributed values, data is usually approximately balanced. |
The database server can eliminate fragments for queries
that have equality expressions. |
You cannot determine if the integrity of the transaction
is compromised when you use the dataskip feature. You cannot insert
rows if the fragment for those rows is not available. |
Hybrid |
You must know the data distribution and queries run
against the table to balance the table I/O across the dbslice. Unless
the hash fragmentation column contains evenly distributed unique values,
hash-fragmented tables do not necessarily completely balance data. |
The database server can eliminate fragments for range
or equality statements on the base-level expression strategy or
equality expressions on the secondary-level hash strategy. |
You can determine whether the integrity of a transaction
has been compromised when you use the dataskip feature. You cannot
insert rows if the fragment for those rows is not available. |
Range |
Data balancing requires dense, uniform, non-duplicate
distribution of fragmentation column data. |
The database server can eliminate fragments for queries
with equality and range expressions. |
You can determine whether the integrity of a transaction
has been compromised when you use the dataskip feature. You cannot
insert rows if the fragment for those rows is not available. |