From 5bffef714f67301b4d00d47c4c0884c5a0272fdb Mon Sep 17 00:00:00 2001 From: Michael Stack Date: Wed, 11 Apr 2018 15:07:27 -0700 Subject: [PATCH] HBASE-20349 [DOC] upgrade guide should call out removal of prefix-tree data block encoding --- src/main/asciidoc/_chapters/upgrading.adoc | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/src/main/asciidoc/_chapters/upgrading.adoc b/src/main/asciidoc/_chapters/upgrading.adoc index 67c5dbc902..85f1151aeb 100644 --- a/src/main/asciidoc/_chapters/upgrading.adoc +++ b/src/main/asciidoc/_chapters/upgrading.adoc @@ -409,6 +409,16 @@ A brief summary of related changes: The Distributed Log Replay feature was broken and has been removed from HBase 2.y+. As a consequence all related configs, metrics, RPC fields, and logging have also been removed. Note that this feature was found to be unreliable in the run up to HBase 1.0, defaulted to being unused, and was effectively removed in HBase 1.2.0 when we started ignoring the config that turns it on (link:https://issues.apache.org/jira/browse/HBASE-14465[HBASE-14465]). If you are currently using the feature, be sure to perform a clean shutdown, ensure all DLR work is complete, and disable the feature prior to upgrading. +[[upgrade2.0.prefix-tree.removed]] +._prefix-tree_ encoding removed + +The prefix-tree encoding was removed from HBase 2.0.0. It was (late!) deprecated in hbase-1.2.7, hbase-1.4.0, and hbase-1.3.2. + +This feature was removed because it as not being actively maintained. If interested in reviving this +sweet facility which improved random read latencies at the expensive of slowed writes, +write the HBase developers list at _dev at hbase dot apache dot org_. + + [[upgrade2.0.metrics]] .Changed metrics -- 2.16.3