The gadget spec URL could not be found
When creating a table, there is an additional clause to declare the Greenplum Database distribution policy. If a DISTRIBUTED BY or DISTRIBUTED RANDOMLY clause is not supplied, then Greenplum assigns a hash distribution policy to the table using either the PRIMARY KEY (if the table has one) or the first column of the table as the distribution key. Columns of geometric or user-defined data types are not eligible as Greenplum distribution key columns. If a table does not have a column of an eligible data type, the rows are distributed based on a round-robin or random distribution. The gadget spec URL could not be found To ensure an even distribution of data, you want to choose a distribution key that is unique for each record, or if that is not possible, then choose DISTRIBUTED RANDOMLY. For example: => CREATE TABLE products (name varchar(40), prod_id integer, supplier_id integer) DISTRIBUTED BY (prod_id); => CREATE TABLE random_stuff (things text, doodads text, etc text) DISTRIBUTED RANDOMLY; Altering Table Distribution ALTER TABLE provides options to change the distribution policy of a table. When the distribution options of a table change, the table data is redistributed on disk, which can be resource intensive. There is also an option to redistribute table data using the existing distribution policy. Changing the Distribution Policy You can use the ALTER TABLE command to change the distribution policy for a table. For partitioned tables, changes to the distribution policy recursively apply to the child partitions. This operation preserves the ownership and all other attributes of the table. For example, the following command redistributes the table sales across all segments using the customer_id column as the distribution key: ALTER TABLE sales SET DISTRIBUTED BY (customer_id); When you change the hash distribution of a table, table data is automatically redistributed. However, changing the distribution policy to a random distribution will not cause the data to be redistributed. For example: ALTER TABLE sales SET DISTRIBUTED RANDOMLY; Redistributing Table Data To redistribute table data for tables with a random distribution policy (or when the hash distribution policy has not changed) use REORGANIZE=TRUE. This sometimes may be necessary to correct a data skew problem, or when new segment resources have been added to the system. For example: ALTER TABLE sales SET WITH (REORGANIZE=TRUE); The gadget spec URL could not be found This command rebalances a table evenly across all segments using the current distribution policy (including random distribution). | The gadget spec URL could not be found |
The gadget spec URL could not be found