From 15b32460f9484fc0c635172c81b6a6315283775a Mon Sep 17 00:00:00 2001
From: anoopsamjohn <anoopsamjohn@gmail.com>
Date: Fri, 27 Oct 2017 11:53:25 +0530
Subject: [PATCH] HBASE-18906 Provide Region#waitForFlushes API.

---
 .../hadoop/hbase/regionserver/HRegion.java    | 26 +++++++++++++------
 .../hadoop/hbase/regionserver/Region.java     |  9 +++++++
 2 files changed, 27 insertions(+), 8 deletions(-)

diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
index f0c9ec28f53..3cb0e549051 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/HRegion.java
@@ -1768,30 +1768,39 @@ public class HRegion implements HeapSize, PropagatingConfigurationObserver, Regi
     }
   }
 
-  /** Wait for all current flushes of the region to complete
+  /**
+   * Wait for all current flushes of the region to complete
    */
-  // TODO HBASE-18906. Check the usage (if any) in Phoenix and expose this or give alternate way for
-  // Phoenix needs.
   public void waitForFlushes() {
+    waitForFlushes(0);// Unbound wait
+  }
+
+  @Override
+  public boolean waitForFlushes(long timeout) {
     synchronized (writestate) {
       if (this.writestate.readOnly) {
         // we should not wait for replayed flushed if we are read only (for example in case the
         // region is a secondary replica).
-        return;
+        return true;
       }
-      if (!writestate.flushing) return;
+      if (!writestate.flushing) return true;
       long start = System.currentTimeMillis();
+      long duration = 0;
       boolean interrupted = false;
+      LOG.debug("waiting for cache flush to complete for region " + this);
       try {
         while (writestate.flushing) {
-          LOG.debug("waiting for cache flush to complete for region " + this);
+          if (timeout > 0 && duration >= timeout) break;
           try {
-            writestate.wait();
+            long toWait = timeout == 0 ? 0 : (timeout - duration);
+            writestate.wait(toWait);
           } catch (InterruptedException iex) {
             // essentially ignore and propagate the interrupt back up
             LOG.warn("Interrupted while waiting");
             interrupted = true;
             break;
+          } finally {
+            duration = System.currentTimeMillis() - start;
           }
         }
       } finally {
@@ -1799,10 +1808,11 @@ public class HRegion implements HeapSize, PropagatingConfigurationObserver, Regi
           Thread.currentThread().interrupt();
         }
       }
-      long duration = System.currentTimeMillis() - start;
       LOG.debug("Waited " + duration + " ms for flush to complete");
+      return !(writestate.flushing);
     }
   }
+
   protected ThreadPoolExecutor getStoreOpenAndCloseThreadPool(
       final String threadNamePrefix) {
     int numStores = Math.max(1, this.htableDescriptor.getColumnFamilyCount());
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/Region.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/Region.java
index c0827cbf04e..a5bad1acb80 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/Region.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/Region.java
@@ -473,4 +473,13 @@ public interface Region extends ConfigurationObserver {
    * Request flush on this region.
    */
   void requestFlush(FlushLifeCycleTracker tracker) throws IOException;
+
+  /**
+   * Wait for all current flushes of the region to complete
+   *
+   * @param timeout The maximum time to wait in milliseconds.
+   * @return False when timeout elapsed but flushes are not over. True when flushes are over within
+   * max wait time period.
+   */
+  boolean waitForFlushes(long timeout);
 }