Apache
/
hbase
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

HBASE-17875 Document why objects over 10MB are not well-suited for hbase. 

Signed-off-by: Sean Busbey <busbey@apache.org>
This commit is contained in:
Jingcheng Du 2017-04-28 13:32:30 -05:00 committed by Sean Busbey
parent ba12cdf138
commit 6edb8f8217
2 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/main/asciidoc/_chapters/faq.adoc
View File

@ -44,6 +44,9 @@ How can I find examples of NoSQL/HBase?::
What is the history of HBase?::
See <<hbase.history,hbase.history>>.
Why are the cells above 10MB not recommended for HBase?::
Large cells don't fit well into HBase's approach to buffering data. First, the large cells bypass the MemStoreLAB when they are written. Then, they cannot be cached in the L2 block cache during read operations. Instead, HBase has to allocate on-heap memory for them each time. This can have a significant impact on the garbage collector within the RegionServer process.
=== Upgrading
How do I upgrade Maven-managed projects from HBase 0.94 to HBase 0.96+?::
In HBase 0.96, the project moved to a modular structure. Adjust your project's dependencies to rely upon the `hbase-client` module or another module as appropriate, rather than a single JAR. You can model your Maven dependency after one of the following, depending on your targeted version of HBase. See Section 3.5, “Upgrading from 0.94.x to 0.96.x” or Section 3.3, “Upgrading from 0.96.x to 0.98.x” for more information.

4
src/main/asciidoc/_chapters/hbase_mob.adoc
View File

@ -36,7 +36,7 @@ read and write paths are optimized for values smaller than 100KB in size. When
HBase deals with large numbers of objects over this threshold, referred to here
as medium objects, or MOBs, performance is degraded due to write amplification
caused by splits and compactions. When using MOBs, ideally your objects will be between
100KB and 10MB. HBase ***FIX_VERSION_NUMBER*** adds support
100KB and 10MB (see the <<faq>>). HBase ***FIX_VERSION_NUMBER*** adds support
for better managing large numbers of MOBs while maintaining performance,
consistency, and low operational overhead. MOB support is provided by the work
done in link:https://issues.apache.org/jira/browse/HBASE-11339[HBASE-11339]. To
@ -155,7 +155,7 @@ family as the second argument. and take a compaction type as the third argument.
----
hbase> compact 't1', 'c1’, ‘MOB’
hbase> major_compact_mob 't1', 'c1’, ‘MOB’
hbase> major_compact 't1', 'c1’, ‘MOB’
----
These commands are also available via `Admin.compact` and