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Posted to dev@hbase.apache.org by Himanshu Vashishtha <va...@gmail.com> on 2010/10/01 00:26:18 UTC
Re: Review Request: [HBASE-2321] [HBASE-2002] Add support for per-region
dynamically registered RPC endpoints for coprocessors and allow
configurable RPC client/server implementations
> On 2010-09-25 16:18:25, Andrew Purtell wrote:
> > src/main/java/org/apache/hadoop/hbase/client/HTable.java, line 1400
> > <http://review.cloudera.org/r/816/diff/5/?file=12533#file12533line1400>
> >
> > Maybe for sake of clarity call this getStartKeysInRange?
>
> Gary Helmling wrote:
> Makes sense as well, will rename.
Gary: I meant this use case (might be irrelevant, considering scope of cp):
If I want to know count of number of rows in a range (Row A, Row B): with the help of this method, I can get the starting row of all regions that are in this range but for the first (where you take the starting row of the range: Row A in this case).
So, when the processing is done in the last region, one shd be aware of the last row in the range, Row B. This processing will be done in the cp impl, but that impl will be same on all region servers, so that check will be there for all regions (no?).
It is entirely possible that this use case is not the one to be supported by cp; or as I haven't really looked at mlai's code thoroughly yet, might be missing something obvious.
- Himanshu
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On 2010-09-24 00:01:53, Gary Helmling wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://review.cloudera.org/r/816/
> -----------------------------------------------------------
>
> (Updated 2010-09-24 00:01:53)
>
>
> Review request for hbase, Andrew Purtell and Jonathan Gray.
>
>
> Summary
> -------
>
> This is really two separate patches in one, though with some overlapping changes. If necessary I can split them apart for separate review. Please let me know if that would make review easier.
>
> Part 1:
> ==============
> Port over of HADOOP-6422 to the HBase RPC code. The goal of this change is to allow alternate RPC client/server implementations to be enabled through a simple configuration change. Ultimately I would like to use this to allow secure RPC to be enabled through configuration, while not blocking normal (current) RPC operation on non-secure Hadoop versions.
>
> This portion of the patch abstracts out two interfaces from the RPC code:
>
> RpcEngine: HBaseRPC uses this to obtain proxy instances for client calls and server instances for HMaster and HRegionServer
> RpcServer: this allows differing RPC server implementations, breaking the dependency on HBaseServer
>
> The bulk of the current code from HBaseRPC is moved into WritableRpcEngine and is unchanged other than the interface requirements. So the current call path remains the same, other than the HBaseRPC.getProtocolEngine() abstraction.
>
>
> Part 2:
> ===============
> The remaining changes provide server-side hooks for registering new RPC protocols/handlers (per-region to support coprocessors), and client side hooks to support dynamic execution of the registered protocols.
>
> The new RPC protocol actions are constrained to org.apache.hadoop.hbase.ipc.CoprocessorProtocol implementations (which extends VersionedProtocol) to prevent arbitrary execution of methods against HMasterInterface, HRegionInterface, etc.
>
> For protocol handler registration, HRegionServer provides a new method:
>
> public <T extends CoprocessorProtocol> boolean registerProtocol(
> byte[] region, Class<T> protocol, T handler)
>
> which builds a Map of region name to protocol instances for dispatching client calls.
>
>
> Client invocations are performed through HTable, which adds the following methods:
>
>
> public <T extends CoprocessorProtocol> T proxy(Class<T> protocol, Row row)
>
> This directly returns a proxy instance to the CoprocessorProtocol implementation registered for the region serving row "row". Any method calls will be proxied to the region's server and invoked using the map of registered region name -> handler instances.
>
> Calls directed against multiple rows are a bit more complicated. They are supported with the methods:
>
> public <T extends CoprocessorProtocol, R> void exec(
> Class<T> protocol, List<? extends Row> rows,
> BatchCall<T,R> callable, BatchCallback<R> callback)
>
> public <T extends CoprocessorProtocol, R> void exec(
> Class<T> protocol, RowRange range,
> BatchCall<T,R> callable, BatchCallback<R> callback)
>
> where BatchCall and BatchCallback are simple interfaces defining the methods to be called and a callback instance to be invoked for each result.
>
> For the sample CoprocessorProtocol interface:
>
> interface PingProtocol extends CoprocessorProtocol {
> public String ping();
> public String hello(String name);
> }
>
> a client invocation might look like:
>
> final Map<byte[],R> results = new TreeMap<byte[],R>(...)
> List<Row> rows = ...
> table.exec(PingProtocol.class, rows,
> new HTable.BatchCall<PingProtocol,String>() {
> public String call(PingProtocol instance) {
> return instance.ping();
> }
> },
> new BatchCallback<R>(){
> public void update(byte[] region, byte[] row, R value) {
> results.put(region, value);
> }
> });
>
> The BatchCall.call() method will be invoked for each row in the passed in list, and the BatchCallback.update() method will be invoked for each return value. However, currently the PingProtocol.ping() invocation will result in a separate RPC call per row, which is less that ideal.
>
> Support is in place to make use of the HRegionServer.multi() invocations for batched RPC (see the org.apache.hadoop.hbase.client.Exec class), but this does not mesh well with the current client-side interface.
>
> In addition to standard code review, I'd appreciate any thoughts on the client interactions in particular, and whether they would meet some of the anticipated uses of coprocessors.
>
>
> This addresses bugs HBASE-2002 and HBASE-2321.
> http://issues.apache.org/jira/browse/HBASE-2002
> http://issues.apache.org/jira/browse/HBASE-2321
>
>
> Diffs
> -----
>
> src/main/java/org/apache/hadoop/hbase/client/Action.java 556ea81
> src/main/java/org/apache/hadoop/hbase/client/Batch.java PRE-CREATION
> src/main/java/org/apache/hadoop/hbase/client/Exec.java PRE-CREATION
> src/main/java/org/apache/hadoop/hbase/client/ExecResult.java PRE-CREATION
> src/main/java/org/apache/hadoop/hbase/client/HConnection.java 65f7618
> src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java fbdec0b
> src/main/java/org/apache/hadoop/hbase/client/HTable.java 0dbf263
> src/main/java/org/apache/hadoop/hbase/client/MultiAction.java c6ea838
> src/main/java/org/apache/hadoop/hbase/client/MultiResponse.java 91bd04b
> src/main/java/org/apache/hadoop/hbase/client/RowRange.java PRE-CREATION
> src/main/java/org/apache/hadoop/hbase/client/Scan.java 29b3cb0
> src/main/java/org/apache/hadoop/hbase/io/HbaseObjectWritable.java 83f623d
> 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 2b5eeb6
> src/main/java/org/apache/hadoop/hbase/ipc/HBaseRPC.java e23a629
> src/main/java/org/apache/hadoop/hbase/ipc/HBaseServer.java e4c356d
> src/main/java/org/apache/hadoop/hbase/ipc/HRegionInterface.java a4810a6
> 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 36ba5c1
> src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java 1be9cf5
> src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java e9d7751
> src/main/resources/hbase-default.xml 5452fd1
> src/test/java/org/apache/hadoop/hbase/regionserver/TestServerCustomProtocol.java PRE-CREATION
>
> Diff: http://review.cloudera.org/r/816/diff
>
>
> Testing
> -------
>
>
> Thanks,
>
> Gary
>
>