svn commit: r1181499 - /hbase/branches/0.89/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java

[ns...@apache.org]

Author: nspiegelberg
Date: Tue Oct 11 02:13:56 2011
New Revision: 1181499

URL: http://svn.apache.org/viewvc?rev=1181499&view=rev
Log:
Parallelize Server Requests on HBase Client

Summary:
Vastly improves HBCK performance on the dark launch.  Although we
are parallelizing getRegionAssignment() calls, getHRegionConnection()
gets a big lock. Cache misses can be expensive on heavily-loaded servers
because they need to setup a proxy connection.  This hurts cache hits on a
cache miss & serializes all
cache misses.  We should parallelize both situations.

Test Plan:
- bin/hbase hbck
 - mvn test

Reviewed By: kannan
Reviewers: jgray, dhruba, kannan, kranganathan
CC: kannan
Tasks:
#510832: Reduce HBCK Latency

Revert Plan:
OK

Differential Revision: 222374

Modified:
    hbase/branches/0.89/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java

Modified: hbase/branches/0.89/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java
URL: http://svn.apache.org/viewvc/hbase/branches/0.89/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java?rev=1181499&r1=1181498&r2=1181499&view=diff
==============================================================================
--- hbase/branches/0.89/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java (original)
+++ hbase/branches/0.89/src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java Tue Oct 11 02:13:56 2011
@@ -292,6 +292,7 @@ public class HConnectionManager {
     // Known region HServerAddress.toString() -> HRegionInterface
     private final Map<String, HRegionInterface> servers =
       new ConcurrentHashMap<String, HRegionInterface>();
+    private final ConcurrentHashMap<String, String> connectionLock = new ConcurrentHashMap<String, String>();
 
     // Used by master and region servers during safe mode only
     private volatile HRegionLocation rootRegionLocation;
@@ -1024,19 +1025,28 @@ public class HConnectionManager {
         getMaster();
       }
       HRegionInterface server;
-      synchronized (this.servers) {
-        // See if we already have a connection
-        server = this.servers.get(regionServer.toString());
-        if (server == null) { // Get a connection
-          try {
-            server = (HRegionInterface)HBaseRPC.waitForProxy(
-                serverInterfaceClass, HBaseRPCProtocolVersion.versionID,
-                regionServer.getInetSocketAddress(), this.conf,
-                this.maxRPCAttempts, (int)this.rpcTimeout, this.rpcTimeout);
-          } catch (RemoteException e) {
-            throw RemoteExceptionHandler.decodeRemoteException(e);
+      String rsName = regionServer.toString();
+      // See if we already have a connection (common case)
+      server = this.servers.get(rsName);
+      if (server == null) {
+        // create a unique lock for this RS (if necessary)
+        this.connectionLock.putIfAbsent(rsName, rsName);
+        // get the RS lock
+        synchronized (this.connectionLock.get(rsName)) {
+          // do one more lookup in case we were stalled above
+          server = this.servers.get(rsName);
+          if (server == null) {
+            try {
+              // definitely a cache miss. establish an RPC for this RS
+              server = (HRegionInterface) HBaseRPC.waitForProxy(
+                  serverInterfaceClass, HBaseRPCProtocolVersion.versionID,
+                  regionServer.getInetSocketAddress(), this.conf,
+                  this.maxRPCAttempts, this.rpcTimeout, this.rpcTimeout);
+              this.servers.put(rsName, server);
+            } catch (RemoteException e) {
+              throw RemoteExceptionHandler.decodeRemoteException(e);
+            }
           }
-          this.servers.put(regionServer.toString(), server);
         }
       }
       return server;