What's new in Greenplum database 4.3
Greenplum Database 4.3 is a major release that introduces a number of significant new features, as well as performance and stability enhancements.
Greenplum Database 4.3 includes enhancements in these areas:
1. Greenplum Database High Availability
2. Append-Optimized Tables
3. Workfile Disk Spill Space Information
1. Greenplum Database High Availability
The Greenplum Database master mirroring feature has been enhanced. With master mirroring, a Greenplum Database backup master or standby master serves as a warm standby if the primary master becomes non-operational.
1. A Greenplum Database standby master is created while Greenplum Database is online. Greenplum Database does not need to be offline.
2. Reboot of the standby master is not required when activating to the standby master to become primary master.
3. Faster switching when Greenplum Database changes from the current active master to the standby master.
The following changes have been made to Greenplum Database:
1. The Greenplum Database utilities gpinitstandby and gpactivatestandby have been changed.
2. Greenplum Database administrative tables and views have been changed
For more information about high availability and master mirroring, see the Greenplum Database System Administration Guide.
2. Append-Optimized Tables
Append-optimized tables are similar to append-only tables and also allow UPDATE and DELETE operations on the table data. When migrating Greenplum Database from 4.2.x.x to 4.3, append-only tables are migrated to append-optimized tables.Migration of database with a large number of append-only tables might require a significant amount of time.
Append-optimized tables works best with denormalized fact tables in a data warehouse environment, where the data is static after it is loaded. Denormalized fact tables are typically the largest tables in the system. Fact tables are usually loaded in batches and accessed by read-only queries. Moving large fact tables to an append-only storage model eliminates the storage overhead of the per-row update visibility information, saving about 20 bytes per row.
IMPORTANT: Append-optimized tables cannot be used with the following functionality:
1. Transactions with serializable isolation levels
2. Updatable cursors
With append-optimized tables, you use the VACUUM command to reclaim the storage capacity from table data that was deleted or updated. For information about creating append-optimized tables, see the CREATE TABLE command in the Greenplum Database Reference Guide. For information about append-optimized tables and using VACUUM command to maintain append-optimized tables, see the Greenplum Database Database Administrator Guide and the Greenplum Database System Administrator Guide.
3. Workfile Disk Spill Space Information
In Greenplum Database 4.3 gp_workfile_* views in the gp_toolkit administrative schema contain show information about all the queries that are currently using disk spill space. Previously in 4.2.x.x releases, you created the views by running SQL scripts. For information about the gp_toolkit administrative views, see the Greenplum Database Reference Guide.