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Posted to issues@hbase.apache.org by "HBase Review Board (JIRA)" <ji...@apache.org> on 2010/11/08 23:44:23 UTC
[jira] Commented: (HBASE-2001) Coprocessors: Colocate user code
with regions
[ https://issues.apache.org/jira/browse/HBASE-2001?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12929784#action_12929784 ]
HBase Review Board commented on HBASE-2001:
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Message from: "Mingjie Lai" <mj...@gmail.com>
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This is an automatically generated e-mail. To reply, visit:
http://review.cloudera.org/r/876/
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(Updated 2010-11-08 14:41:41.575886)
Review request for hbase, stack, Andrew Purtell, and Jonathan Gray.
Changes
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Changes:
- Addressed Stack's comments.
- Renamed CommandTarget to Endpoint (still up to decide whether it's better or not)
- Improved package-info.
- Refined some of RegionObserver method signatures, i.e., preGet(), etc.
- Added hooks for HTable.increment(Increment).
Summary (updated)
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The diff actually contains 2 seperate patches: HBase-2001 and the one for (HBASE-2002+HBASE-2321). The reason is that HBase-2001's CommandTarget relies on HBASE-2002 + HBASE-2321 which patches are still under review. I have to include Gary's HBASE-2002, HBASE-2321 with this diff, since reviewboard is so powerful :) and it disallow my diff to be based on some unchecked in patch.
Eventually the patch here should be committed after 2001 and 2321. I will make another patch after they got checked in.
Both HBase-2001 and the dynamic RPC stuff are quite big patches. Total number of lines are more than 7k. I turned back and forth, but still don't have a good idea to create the patch in order to reduce the review pain. However right now I'm putting the whole patch for all the 3 issues. Here the list of file which are only related to coprocessor:
src/main/java/org/apache/hadoop/hbase/coprocessor/BaseEndpointCoprocessor.java
src/main/java/org/apache/hadoop/hbase/coprocessor/BaseRegionObserverCoprocessor.java
src/main/java/org/apache/hadoop/hbase/coprocessor/Coprocessor.java
src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorEnvironment.java
src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorException.java
src/main/java/org/apache/hadoop/hbase/coprocessor/RegionObserver.java
src/main/java/org/apache/hadoop/hbase/coprocessor/package-info.java
src/main/java/org/apache/hadoop/hbase/regionserver/CoprocessorHost.java
src/test/java/org/apache/hadoop/hbase/coprocessor/ColumnAggregationEndpoint.java
src/test/java/org/apache/hadoop/hbase/coprocessor/ColumnAggregationProtocol.java
src/test/java/org/apache/hadoop/hbase/coprocessor/SimpleRegionObserver.java
src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorEndpoint.java
src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorInterface.java
src/test/java/org/apache/hadoop/hbase/coprocessor/TestRegionObserverInterface.java
src/test/java/org/apache/hadoop/hbase/coprocessor/TestRegionObserverStacking.java
==========================
(Here is a brief description. Please find much more details at the package-info.java in the diff. I also post the package-info.html to https://issues.apache.org/jira/browse/HBASE-2001 as an attachment.)
Coprocessors are code that runs in-process on each region server. Regions contain references to the coprocessor implementation classes associated with them. Coprocessor classes will be loaded either from local jars on the region server's classpath or via the HDFS classloader.
Multiple types of coprocessors are provided to provide sufficient flexibility for potential use cases. Right now there are:
* Coprocessor: provides region lifecycle management hooks, e.g., region open/close/split/flush/compact operations.
* RegionObserver: provides hook for monitor table operations from client side, such as table get/put/scan/delete, etc.
* Endpoint: provides on demand triggers for any arbitrary function executed at a region. One use case is column aggregation at region server.
Coprocessor:
A coprocessor is required to implement Coprocessor interface so that coprocessor framework can manage it internally.
Another design goal of this interface is to provide simple features for making coprocessors useful, while exposing no more internal state or control actions of the region server than necessary and not exposing them directly.
RegionObserver
If the coprocessor implements the RegionObserver interface it can observe and mediate client actions on the region.
Endpoint:
Coprocessor and RegionObserver provide certain hooks for injecting user code running at each region. These code will be triggerd with existing HTable and HBaseAdmin operations at the certain hook points.
Through Endpoint and dynamic RPC protocol, you can define your own interface communicated between client and region server, i.e., you can create a new method, specify passed parameters and return types for the method. And the new Endpoint methods can be triggered by calling client side dynamic RPC functions -- HTable.exec(...).
Coprocess loading
A customized coprocessor can be loaded by two different ways, by configuration, or by HTableDescriptor for a newly created table.
(Currently we don't really have an on demand coprocessor loading machanism for opened regions. However it should be easy to create a dedicated CommandTarget for coprocessor loading)
This addresses bug HBase-2001.
http://issues.apache.org/jira/browse/HBase-2001
Diffs (updated)
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src/main/java/org/apache/hadoop/hbase/client/Action.java 556ea81
src/main/java/org/apache/hadoop/hbase/client/HConnection.java 3235a9b
src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java 1748a4f
src/main/java/org/apache/hadoop/hbase/client/HTable.java 69dc916
src/main/java/org/apache/hadoop/hbase/client/HTableInterface.java ade3e21
src/main/java/org/apache/hadoop/hbase/client/MultiAction.java c6ea838
src/main/java/org/apache/hadoop/hbase/client/MultiResponse.java 1ac7671
src/main/java/org/apache/hadoop/hbase/client/coprocessor/Batch.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/client/coprocessor/Exec.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/client/coprocessor/ExecResult.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/client/coprocessor/package-info.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/coprocessor/BaseEndpointCoprocessor.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/coprocessor/BaseRegionObserverCoprocessor.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/coprocessor/Coprocessor.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorEnvironment.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/coprocessor/CoprocessorException.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/coprocessor/RegionObserver.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/coprocessor/package-info.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/io/HbaseObjectWritable.java 30dd877
src/main/java/org/apache/hadoop/hbase/ipc/ConnectionHeader.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/ipc/CoprocessorProtocol.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/ipc/ExecRPCInvoker.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/ipc/HBaseClient.java f8d8af7
src/main/java/org/apache/hadoop/hbase/ipc/HBaseRPC.java 4f4828b
src/main/java/org/apache/hadoop/hbase/ipc/HBaseServer.java e4c356d
src/main/java/org/apache/hadoop/hbase/ipc/HRegionInterface.java cf30cf9
src/main/java/org/apache/hadoop/hbase/ipc/Invocation.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/ipc/RpcEngine.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/ipc/RpcServer.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/ipc/WritableRpcEngine.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/master/HMaster.java 209c291
src/main/java/org/apache/hadoop/hbase/regionserver/CoprocessorHost.java PRE-CREATION
src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java dd2955d
src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java ab183e5
src/main/java/org/apache/hadoop/hbase/regionserver/RegionServerServices.java 1309f93
src/main/java/org/apache/hadoop/hbase/regionserver/SplitTransaction.java 1bcde8c
src/main/java/org/apache/hadoop/hbase/regionserver/handler/OpenRegionHandler.java ace7997
src/main/java/org/apache/hadoop/hbase/rest/client/RemoteHTable.java 5f05079
src/main/resources/hbase-default.xml 5fafe65
src/test/java/org/apache/hadoop/hbase/coprocessor/ColumnAggregationEndpoint.java PRE-CREATION
src/test/java/org/apache/hadoop/hbase/coprocessor/ColumnAggregationProtocol.java PRE-CREATION
src/test/java/org/apache/hadoop/hbase/coprocessor/SimpleRegionObserver.java PRE-CREATION
src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorEndpoint.java PRE-CREATION
src/test/java/org/apache/hadoop/hbase/coprocessor/TestCoprocessorInterface.java PRE-CREATION
src/test/java/org/apache/hadoop/hbase/coprocessor/TestRegionObserverInterface.java PRE-CREATION
src/test/java/org/apache/hadoop/hbase/coprocessor/TestRegionObserverStacking.java PRE-CREATION
src/test/java/org/apache/hadoop/hbase/regionserver/TestServerCustomProtocol.java PRE-CREATION
Diff: http://review.cloudera.org/r/876/diff
Testing
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Thanks,
Mingjie
> Coprocessors: Colocate user code with regions
> ---------------------------------------------
>
> Key: HBASE-2001
> URL: https://issues.apache.org/jira/browse/HBASE-2001
> Project: HBase
> Issue Type: Sub-task
> Reporter: Andrew Purtell
> Assignee: Mingjie Lai
> Fix For: 0.92.0
>
> Attachments: asm-transformations.pdf, HBASE-2001-RegionObserver-2.patch, HBASE-2001-RegionObserver.patch, HBASE-2001.patch.gz, packge-info.html, packge-info.html
>
>
> Support user code that runs run next to each region in table. As regions split and move, coprocessor code should automatically move also.
> Use classloader which looks on HDFS.
> Associate a list of classes to load with each table. Put this in HRI so it inherits from table but can be changed on a per region basis (so then those region specific changes can inherited by daughters).
> Not completely arbitrary code, should require implementation of an interface with callbacks for:
> * Open
> * Close
> * Split
> * Compact
> * (Multi)get and scanner next()
> * (Multi)put
> * (Multi)delete
> Add method to HRegionInterface for invoking coprocessor methods and retrieving results.
> Add methods in o.a.h.h.regionserver or subpackage which implement convenience functions for coprocessor methods and consistent/controlled access to internals: store access, threading, persistent and ephemeral state, scratch storage, etc.
> GitHub: http://github.com/mlai/hbase/tree/0.90_coprocessor
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