From 7270cd4f7b2b9b55a8239392128b3e3a2fb86461 Mon Sep 17 00:00:00 2001 From: zjushch Date: Wed, 27 Mar 2013 03:08:12 +0000 Subject: [PATCH] HBASE-8190 Add documentation of region merges to the book git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1461396 13f79535-47bb-0310-9956-ffa450edef68 --- src/docbkx/book.xml | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/src/docbkx/book.xml b/src/docbkx/book.xml index 9beebd530f9..f39132d4ca5 100644 --- a/src/docbkx/book.xml +++ b/src/docbkx/book.xml @@ -2175,6 +2175,28 @@ myHtd.setValue(HTableDescriptor.SPLIT_POLICY, MyCustomSplitPolicy.class.getName( + +
+ Online Region Merges + + Both Master and Regionserver participate in the event of online region merges. + Client sends merge RPC to master, then master moves the regions together to the + same regionserver where the more heavily loaded region resided, finally master + send merge request to this regionserver and regionserver run the region merges. + Similar with process of region splits, region merges run as a local transaction + on the regionserver, offlines the regions and then merges two regions on the file + system, atomically delete merging regions from META and add merged region to the META, + opens merged region on the regionserver and reports the merge to Master at last. + + An example of region merges in the hbase shell + $ hbase> merge_region 'ENCODED_REGIONNAME', 'ENCODED_REGIONNAME' + hbase> merge_region 'ENCODED_REGIONNAME', 'ENCODED_REGIONNAME', true + + It's an asynchronous operation and call returns immediately without waiting merge completed. + Passing 'true' as the optional third parameter will force a merge ('force' merges regardless + else merge will fail unless passed adjacent regions. 'force' is for expert use only) + +
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