Time Zone Management

Vertica no longer requires that the default time zone be the same on all cluster hosts.

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When a client receives the result set of an SQL query, all rows contain data adjusted, if necessary, to the same time zone. That time zone is the default time zone of the initiator node unless the client explicitly overrides it using the SQL SET TIMEZONE command (described in the SQL Reference Manual). The default time zone of any node is controlled by the TZ environment variable or, if TZ is undefined, the operating system time zone.

Configuring Multiple Time Zones

As a convenience to clients in multiple time zones, you can designate specific nodes as having specific default time zones. This allows a client to connect to a specific node and execute SQL statements using the default SQL time zone. In other words, there is no need for the client to use the SQL SET TIMEZONE command.

If you do this, however, be aware that:

• the install_vertica script (described in Installing Vertica) issues warnings when the TZ (and LANG) environment variables are not the same on all cluster hosts
• a client that does not use the SQL SET TIMEZONE command may get unexpected query results if it connects to the wrong node
• the timestamps in the each node's log files are based on its default time zone and thus may be different across the cluster

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