HBASE-1191 ZooKeeper ensureParentExists calls fail

on absolute path (via Nitay Joffe)
HBASE-1187  After disabling/enabling a table, the regions seems to
               be assigned to only 1-2 region servers


git-svn-id: https://svn.apache.org/repos/asf/hadoop/hbase/trunk@742137 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -46,6 +46,10 @@ Release 0.20.0 - Unreleased
                (Toby White via Andrew Purtell)
    HBASE-1180  Add missing import statements to SampleUploader and remove
                unnecessary @Overrides (Ryan Smith via Andrew Purtell)
+   HBASE-1191  ZooKeeper ensureParentExists calls fail 
+               on absolute path (via Nitay Joffe)
+   HBASE-1187  After disabling/enabling a table, the regions seems to 
+               be assigned to only 1-2 region servers
 
 Release 0.19.0 - 01/21/2009
   INCOMPATIBLE CHANGES

conf/hbase-default.xml

@@ -225,6 +225,13 @@
     takes longer than this interval, assign to a new regionserver.
     </description>
   </property>
+  <property>
+    <name>hbase.regions.percheckin</name>
+    <value>10</value>
+    <description>Maximum number of regions that can be assigned in a single go
+    to a region server.
+    </description>
+  </property>
   <property>
     <name>hbase.server.thread.wakefrequency</name>
     <value>10000</value>

src/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWrapper.java

@@ -214,29 +214,38 @@ public class ZooKeeperWrapper implements HConstants {
     return address;
   }
 
-  private boolean ensureZNodeExists(String path) {
+  private boolean ensureExists(final String znode) {
     try {
-      zooKeeper.create(path, new byte[0],
+      zooKeeper.create(znode, new byte[0],
                        Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
-      LOG.debug("Created ZNode " + path);
+      LOG.debug("Created ZNode " + znode);
       return true;
     } catch (KeeperException.NodeExistsException e) {
       return true;      // ok, move on.
+    } catch (KeeperException.NoNodeException e) {
+      return ensureParentExists(znode) && ensureExists(znode);
     } catch (KeeperException e) {
-      LOG.warn("Failed to create " + parentZNode + ": " + e);
+      LOG.warn("Failed to create " + znode + ":", e);
     } catch (InterruptedException e) {
-      LOG.warn("Failed to create " + parentZNode + ": " + e);
+      LOG.warn("Failed to create " + znode + ":", e);
     }
-
     return false;
   }
 
+  private boolean ensureParentExists(final String znode) {
+    int index = znode.lastIndexOf(ZNODE_PATH_SEPARATOR);
+    if (index <= 0) {   // Parent is root, which always exists.
+      return true;
+    }
+    return ensureExists(znode.substring(0, index));
+  }
+
   /**
    * Delete ZNode containing root region location.
    * @return true if operation succeeded, false otherwise.
    */
   public boolean deleteRootRegionLocation()  {
-    if (!ensureZNodeExists(parentZNode)) {
+    if (!ensureParentExists(rootRegionZNode)) {
       return false;
     }
 
@@ -297,7 +306,7 @@ public class ZooKeeperWrapper implements HConstants {
       return deleteRootRegionLocation();
     }
 
-    if (!ensureZNodeExists(parentZNode)) {
+    if (!ensureParentExists(rootRegionZNode)) {
       return false;
     }
 
@@ -316,7 +325,7 @@ public class ZooKeeperWrapper implements HConstants {
    * @return true if we're out of safe mode, false otherwise.
    */
   public boolean checkOutOfSafeMode() {
-    if (!ensureZNodeExists(parentZNode)) {
+    if (!ensureParentExists(outOfSafeModeZNode)) {
       return false;
     }
 
@@ -328,7 +337,7 @@ public class ZooKeeperWrapper implements HConstants {
    * @return true if ephemeral ZNode created successfully, false otherwise.
    */
   public boolean writeOutOfSafeMode() {
-    if (!ensureZNodeExists(parentZNode)) {
+    if (!ensureParentExists(outOfSafeModeZNode)) {
       return false;
     }
 
@@ -353,8 +362,7 @@ public class ZooKeeperWrapper implements HConstants {
    * @return true if the location was written, false if it failed
    */
   public boolean writeRSLocation(HServerInfo info) {
-    ensureZNodeExists(parentZNode);
-    ensureZNodeExists(rsZNode);
+    ensureExists(rsZNode);
     byte[] data = Bytes.toBytes(info.getServerAddress().getBindAddress());
     String znode = rsZNode + ZNODE_PATH_SEPARATOR + info.getStartCode();
     try {

src/test/org/apache/hadoop/hbase/TestZooKeeper.java

@@ -62,4 +62,13 @@ public class TestZooKeeper extends HBaseClusterTestCase {
     masterRootAddress = master.getRootRegionLocation();
     assertEquals(masterRootAddress, zooKeeperRootAddress);
   }
+
+  /**
+   * @throws IOException
+   */
+  public void testParentExists() throws IOException {
+    conf.set("zookeeper.znode.safemode", "/a/b/c/d/e");
+    ZooKeeperWrapper zooKeeper = new ZooKeeperWrapper(conf);
+    assertTrue(zooKeeper.writeOutOfSafeMode());
+  }
 }