(accumulo) branch elasticity updated: Replace logic for determining whether a Tablet is in use (#3920)

[dlmarion]

This is an automated email from the ASF dual-hosted git repository.

dlmarion pushed a commit to branch elasticity
in repository https://gitbox.apache.org/repos/asf/accumulo.git


The following commit(s) were added to refs/heads/elasticity by this push:
     new 4483c90068 Replace logic for determining whether a Tablet is in use 
(#3920)
4483c90068 is described below

commit 4483c9006829245422fa8e2b7f3764d1e7f3329f
Author: Dave Marion <dlmar...@apache.org>
AuthorDate: Thu Nov 2 12:01:06 2023 -0400

    Replace logic for determining whether a Tablet is in use (#3920)
    
    The previous logic used the ingest and scan rates and would
    say a Tablet was not in use when the rates were zero. However,
    due to a smoothing function on the Rate class, this may not
    happen or would take a really long time. The logic was modified
    to use the internal Tablet activeScans and writesInProgress
    variables to determine if activity was currently happening
    instead of using the Rate-based metrics.
    
    Fixes #3907
    
    
    Co-authored-by: Keith Turner <ktur...@apache.org>
---
 .../main/java/org/apache/accumulo/tserver/TabletServer.java  |  7 +------
 .../main/java/org/apache/accumulo/tserver/tablet/Tablet.java |  8 ++++++++
 .../accumulo/test/functional/OnDemandTabletUnloadingIT.java  | 12 +++---------
 3 files changed, 12 insertions(+), 15 deletions(-)

diff --git 
a/server/tserver/src/main/java/org/apache/accumulo/tserver/TabletServer.java 
b/server/tserver/src/main/java/org/apache/accumulo/tserver/TabletServer.java
index cc06d8f01b..fba3c57e81 100644
--- a/server/tserver/src/main/java/org/apache/accumulo/tserver/TabletServer.java
+++ b/server/tserver/src/main/java/org/apache/accumulo/tserver/TabletServer.java
@@ -1141,12 +1141,7 @@ public class TabletServer extends AbstractServer 
implements TabletHostingServer
     if (t == null) {
       return false;
     }
-    t.updateRates(System.currentTimeMillis());
-    if (t.ingestRate() != 0.0 && t.queryRate() != 0.0 && t.scanRate() != 0.0) {
-      // tablet is ingesting or scanning
-      return true;
-    }
-    return false;
+    return t.isInUse();
   }
 
   public void evaluateOnDemandTabletsForUnload() {
diff --git 
a/server/tserver/src/main/java/org/apache/accumulo/tserver/tablet/Tablet.java 
b/server/tserver/src/main/java/org/apache/accumulo/tserver/tablet/Tablet.java
index 5fda28f1fe..e74a703095 100644
--- 
a/server/tserver/src/main/java/org/apache/accumulo/tserver/tablet/Tablet.java
+++ 
b/server/tserver/src/main/java/org/apache/accumulo/tserver/tablet/Tablet.java
@@ -1597,4 +1597,12 @@ public class Tablet extends TabletBase {
     this.lastAccessTime = System.nanoTime();
   }
 
+  public synchronized boolean isInUse() {
+    // We can't use the lastAccessTime to determine if a Tablet is in use
+    // because it is only set when TabletServer.getOnlineTablet is called
+    // **and** that method is not called in every case where the Tablet
+    // is used.
+    return !activeScans.isEmpty() || writesInProgress > 0;
+  }
+
 }
diff --git 
a/test/src/main/java/org/apache/accumulo/test/functional/OnDemandTabletUnloadingIT.java
 
b/test/src/main/java/org/apache/accumulo/test/functional/OnDemandTabletUnloadingIT.java
index 6578927ea2..1c9de1da24 100644
--- 
a/test/src/main/java/org/apache/accumulo/test/functional/OnDemandTabletUnloadingIT.java
+++ 
b/test/src/main/java/org/apache/accumulo/test/functional/OnDemandTabletUnloadingIT.java
@@ -160,17 +160,11 @@ public class OnDemandTabletUnloadingIT extends 
SharedMiniClusterBase {
       assertEquals(4, stats.size());
       assertTrue(ClientTabletCache.getInstance((ClientContext) c, 
TableId.of(tableId))
           .getTabletHostingRequestCount() > 0);
-
-      while (ONDEMAND_ONLINE_COUNT != 4) {
-        Thread.sleep(100);
-      }
+      Wait.waitFor(() -> ONDEMAND_ONLINE_COUNT == 4);
 
       // Waiting for tablets to be unloaded due to inactivity
-      while (stats.size() != 0) {
-        Thread.sleep(1000);
-        stats = ManagerAssignmentIT.getTabletStats(c, tableId);
-      }
-
+      Wait.waitFor(() -> ONDEMAND_ONLINE_COUNT == 0);
+      Wait.waitFor(() -> ManagerAssignmentIT.getTabletStats(c, tableId).size() 
== 0);
     }
   }