Javadoc on what BLOCKSIZE means (related to HBASE-15248)

Project: http://git-wip-us.apache.org/repos/asf/hbase/repo
Commit: http://git-wip-us.apache.org/repos/asf/hbase/commit/4beae9a5
Tree: http://git-wip-us.apache.org/repos/asf/hbase/tree/4beae9a5
Diff: http://git-wip-us.apache.org/repos/asf/hbase/diff/4beae9a5

Branch: refs/heads/hbase-12439
Commit: 4beae9a56e2d5d2992d017ba876d18f78415e067
Parents: 7fa7156
Author: Michael Stack <[email protected]>
Authored: Mon Mar 6 15:53:13 2017 -0800
Committer: Michael Stack <[email protected]>
Committed: Mon Mar 6 15:53:13 2017 -0800

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 .../main/java/org/apache/hadoop/hbase/HColumnDescriptor.java    | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
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http://git-wip-us.apache.org/repos/asf/hbase/blob/4beae9a5/hbase-client/src/main/java/org/apache/hadoop/hbase/HColumnDescriptor.java
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diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/HColumnDescriptor.java 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/HColumnDescriptor.java
index 6d1ae3f..e571aae 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/HColumnDescriptor.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/HColumnDescriptor.java
@@ -103,7 +103,10 @@ public class HColumnDescriptor implements 
Comparable<HColumnDescriptor> {
   /**
    * Size of storefile/hfile 'blocks'.  Default is {@link #DEFAULT_BLOCKSIZE}.
    * Use smaller block sizes for faster random-access at expense of larger
-   * indices (more memory consumption).
+   * indices (more memory consumption). Note that this is a soft limit and that
+   * blocks have overhead (metadata, CRCs) so blocks will tend to be the size
+   * specified here and then some; i.e. don't expect that setting BLOCKSIZE=4k
+   * means hbase data will align with an SSDs 4k page accesses (TODO).
    */
   public static final String BLOCKSIZE = "BLOCKSIZE";
 

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