Materialization Options Dialog
This dialog allows to configure advanced materialization
options. Supported options are:
Redshift Distribution Style
When data is loaded into a table, Amazon Redshift distributes
the rows of the table to each of the node slices according to the
table's distribution style. Possible distribution styles are as
follows:
- EVEN: The data in the table is spread evenly across
the nodes in a cluster in a round-robin distribution. Row IDs are
used to determine the distribution, and roughly the same number of
rows are distributed to each node. This distribution method is the
default.
- KEY: The data is distributed by the values in the
DISTKEY column. When you set the joining columns of joining tables as
distribution keys, the joining rows from both tables are collocated
on the compute nodes. When data is collocated, the optimizer can
perform joins more efficiently. If you specify DISTSTYLE KEY, you
must name a DISTKEY column, either for the table or as part of the
column definition.
Please note, some tables may already have a
corresponding optimizations with DISTKEY indexes. Those indexes are
not editable anymore and marked with a corresponding DISTKEY icon. In
case the other DISTKEY column needs be set, the corresponding index
declaration from Optimizations View must be manually removed.
- ALL: A copy of the entire table is distributed to
every node. This distribution style ensures that all the rows
required for any join are available on every node, but it multiplies
storage requirements and increases the load and maintenance times for
the table. ALL distribution can improve execution time when used with
certain dimension tables where KEY distribution is not appropriate,
but performance improvements must be weighed against maintenance
costs.