From 43376c6e061710651fcb3d78274798c159db53d9 Mon Sep 17 00:00:00 2001 From: James Rodewig Date: Wed, 19 Feb 2020 09:14:22 -0500 Subject: [PATCH] [DOCS] Document how CCS handles cluster-level settings (#49941) Updates the cross-cluster search (CCS) documentation to note how cluster-level settings are applied. When `ccs_minimize_roundtrips` is `true`, each cluster applies its own cluster-level settings to the request. When `ccs_minimize_roundtrips` is `false`, cluster-level settings for the local cluster is used. This includes shard limit settings, such as `action.search.shard_count.limit`, `pre_filter_shard_size`, and `max_concurrent_shard_requests`. If these limits are set too low, the request could be rejected. --- docs/reference/modules/cross-cluster-search.asciidoc | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/docs/reference/modules/cross-cluster-search.asciidoc b/docs/reference/modules/cross-cluster-search.asciidoc index 0bad29da0d3..33a159a184e 100644 --- a/docs/reference/modules/cross-cluster-search.asciidoc +++ b/docs/reference/modules/cross-cluster-search.asciidoc @@ -306,7 +306,8 @@ cluster receives and parses the request. image:images/ccs/ccs-min-roundtrip-client-request.svg[] . The coordinating node sends a single search request to each cluster, including -its own. Each cluster performs the search request independently. +the local cluster. Each cluster performs the search request independently, +applying its own cluster-level settings to the request. + image:images/ccs/ccs-min-roundtrip-cluster-search.svg[] @@ -344,6 +345,15 @@ image:images/ccs/ccs-min-roundtrip-cluster-results.svg[] . The coordinating node sends a search request to each shard, including those in its own cluster. Each shard performs the search request independently. + +[WARNING] +==== +When network roundtrips aren't minimized, the search is executed as if all data +were in the coordinating node's cluster. We recommend updating cluster-level +settings that limit searches, such as `action.search.shard_count.limit`, +`pre_filter_shard_size`, and `max_concurrent_shard_requests`, to account for +this. If these limits are too low, the search may be rejected. +==== ++ image:images/ccs/ccs-dont-min-roundtrip-shard-search.svg[] . Each shard sends its search results back to the coordinating node.