From bc6fb8995123d08e672bdcf55bd35165509d60d9 Mon Sep 17 00:00:00 2001 From: Monty Taylor Date: Tue, 16 Jan 2018 11:32:12 -0600 Subject: [PATCH] Add a note about the cost of COPY for setting metadata The pointer to using COPY to the same object as a mechanism to set only a subset of the metadata, it does not mention that doing so results in a full copy of the object in question on the backend. Add a note so it's clear that there is a tradeoff involved. Change-Id: I0c20a4909a6c3ff672f753d26cb9fb2f5f33d1f4 --- api-ref/source/storage-object-services.inc | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/api-ref/source/storage-object-services.inc b/api-ref/source/storage-object-services.inc index 96816997eb..d1e5e7868b 100644 --- a/api-ref/source/storage-object-services.inc +++ b/api-ref/source/storage-object-services.inc @@ -650,6 +650,12 @@ metadata on the request to copy the object, either PUT or COPY , the metadata overwrites any conflicting keys on the target (new) object. +.. note:: + + While using COPY instead of POST allows sending only a subset of + the metadata, it carries the cost of reading and rewriting the entire + contents of the object. + A POST request deletes any existing custom metadata that you added with a previous PUT or POST request. Consequently, you must specify all custom metadata in the request. However, system metadata is