From bf141a3fd18e523e7c32edb0992e2751077e38d2 Mon Sep 17 00:00:00 2001 From: Mueed Chaudhry Date: Wed, 9 May 2018 12:53:55 -0400 Subject: [PATCH] [docs] add warning for read-write indices in force merge documentation (#28869) --- docs/reference/indices/forcemerge.asciidoc | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/docs/reference/indices/forcemerge.asciidoc b/docs/reference/indices/forcemerge.asciidoc index d04ed293168d4..57fe746d59bb2 100644 --- a/docs/reference/indices/forcemerge.asciidoc +++ b/docs/reference/indices/forcemerge.asciidoc @@ -10,6 +10,11 @@ This call will block until the merge is complete. If the http connection is lost, the request will continue in the background, and any new requests will block until the previous force merge is complete. +WARNING: Force merge should only be called against *read-only indices*. Running +force merge against a read-write index can cause very large segments to be produced +(>5Gb per segment), and the merge policy will never consider it for merging again until +it mostly consists of deleted docs. This can cause very large segments to remain in the shards. + [source,js] -------------------------------------------------- POST /twitter/_forcemerge