DEPOT_FETCH

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. It is valid only for Eon mode, otherwise ignored.

Syntax

SELECT /*+ DEPOT_FETCH (option)*/ …

Arguments

option

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

  • ALL: 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;