What's New in Version 5.2

Version 5.2.0 contains the following new features and enhancements. There are also some significant changes in behavior.

Query Planning Enhancements

A number of enhancements have been made in query planning for this release:
  • General improvements in join ordering
  • Better use of declared primary and foreign keys in query planning
  • Improved estimates of join cost and cardinality of matching key values
  • Various improvements and adjustments to the EXPLAIN command output

Tech Preview: Table-Level Restart Option

This option mitigates certain replication failures by not requiring a complete rollback of the replication transaction when a failure occurs. Instead of rolling back the whole transaction to its state before the cycle began, only the table that experienced the failure has its changes rolled back. For a long-running replication cycle that involves a large number of tables, this ability to restart rather than completely redo a replication cycle may save hours or days of effort when the failure is resolved and the cycle is resumed.

Minimum Configuration for Andromeda Platform

The Andromeda platform supports a new three-node minimum configuration. 

System View Updates

The following system views are changed in Version 5.2:
  • sys.replica has a new is_table_level_restart column.
  • sys.replica_status and sys.log_replica_status both have a new retries column.

Encryption Keystore Alert

A new user-defined system alert is triggered when the encryption keystore is locked.

ybcli Changes

The SSD section of the blade status output has been reformatted and now includes the SSD firmware version. Note that on the Andromeda platform the blade status output includes an additional line with BMC and FPGA information.

ybtools Changes

In previous releases, RPMs for ybtools on RHEL and AIX systems had to be installed in the default location (/opt/ybtools). In Version 5.2, you can specify an alternative path.

The ybdumpschema and ybdumproles help text has been updated for consistency. In previous releases, there were some unnecessary differences in the output for the two tools.

SQL Changes

In CREATE TABLE, the ON keyword is now supported for DISTRIBUTE ON RANDOM and DISTRIBUTE ON REPLICATE. Previously, the ON keyword was only supported for hash distribution (DISTRIBUTE ON column).

The default transaction isolation level can be changed only by internal system users. The only supported transaction isolation level that superusers can set is read committed.

The DEALLOCATE command now has an IF EXISTS option.

The ADD_MONTHS function always returns the last day of the result month when the input expression is the last day of the month. For example, 2000 was a leap year. Therefore, 2000-02-28 + 1 month returns 2000-03-28, and 2000-02-29 + 1 month returns 2000-03-31.