Refreshes projections in the current schema with the latest data of their respective.

Refreshes projections in the current schema with the latest data of their respective anchor tables. START_REFRESH runs asynchronously in the background, and updates the PROJECTION_REFRESHES system table. This function has no effect if a refresh is already running.

To refresh only projections of a specific table, use REFRESH. When you deploy a design through Database Designer, it automatically refreshes its projections.

If a refresh would violate a table or schema disk quota, the operation fails. For more information, see Disk quotas.

This is a meta-function. You must call meta-functions in a top-level SELECT statement.

Behavior type







All nodes must be up.

Refresh methods

Vertica can refresh a projection from one of its buddies, if one is available. In this case, the target projection gets the source buddy's historical data. Otherwise, the projection is refreshed from scratch with data of the latest epoch at the time of the refresh operation. In this case, the projection cannot participate in historical queries on any epoch that precedes the refresh operation.

Vertica can perform incremental refreshes when the following conditions are met:

  • The table being refreshed is partitioned.

  • The table does not contain any unpartitioned data.

  • The operation is a full projection refresh (not a partition range projection refresh).

In an incremental refresh, the refresh operation first loads data from the partition with the highest range of keys. After refreshing this partition, Vertica begins to refresh the partition with next highest partition range. This process continues until all projection partitions are refreshed. While the refresh operation is in progress, projection partitions that have completed the refresh process become available to process query requests.

The method used to refresh a given projection is recorded in the REFRESH_METHOD column of the PROJECTION_REFRESHES system table.


 Starting refresh background process.
(1 row)

See also