Vertica Analytics Platform Version 10.0.x Documentation

DEPOT_FETCH

Eon Mode only

Specifies whether a query fetches data to the depot from communal storage when the depot lacks data for this query. This hint overrides configuration parameter DepotOperationsForQuery.

Syntax

SELECT /*+ DEPOT_FETCH (option)*/ …

Arguments

option

Specifies behavior when the depot does not contain queried file data, one of the following:

  • ALL (default): Fetch file data from communal storage, if necessary displace existing files by evicting them from the depot.
  • FETCHES: Fetch file data from communal storage only if space is available; otherwise, read the queried data directly from communal storage.
  • NONE: Do not fetch file data to the depot, read the queried data directly from communal storage.

Examples

SELECT /*+DEPOT_FETCH(All)*/ count(*) FROM bar; 
SELECT /*+DEPOT_FETCH(FETCHES)*/ count(*) FROM bar; 
SELECT /*+DEPOT_FETCH(NONE)*/ count(*) FROM bar;