Improve Tracing

 - Introduce pattern tracing, that can intercept failed or new coordinations matching various filters
 - Support additional tracing event collection modes (SAMPLE and RING)

patch by Benedict; reviewed by Alex Petrov for CASSANDRA-20911

Author: belliottsmith

.gitmodules

@@ -1,4 +1,4 @@
 [submodule "modules/accord"]
 	path = modules/accord
 	url = https://github.com/belliottsmith/cassandra-accord.git
-	branch = rebootstrap-sq
+	branch = improve-tracing

modules/accord

@@ -564,6 +564,9 @@ public EagerColumnsCollector(Consumer<ColumnsCollector> add)
             public <V1, V2> ColumnsCollector add(String name, V1 v1, Function<? super V1, ? extends V2> f1, Function<? super V2, ?> f2)
             {
                 ColumnMetadata cm = columnLookup.get(name);
+                if (cm == null)
+                    throw new IllegalArgumentException("Unknown column name " + name);
+
                 if (!columnFilter.fetches(cm))
                     return this;
 

src/java/org/apache/cassandra/db/virtual/AbstractLazyVirtualTable.java

@@ -21,8 +21,7 @@
 
 import javax.annotation.Nullable;
 
-import org.apache.cassandra.db.Clustering;
-import org.apache.cassandra.db.ClusteringPrefix;
+import accord.utils.Invariants;
 import org.apache.cassandra.db.DeletionInfo;
 import org.apache.cassandra.db.RangeTombstone;
 import org.apache.cassandra.db.Slice;
@@ -70,7 +69,7 @@ protected void applyRowDeletion(Object[] partitionKey, @Nullable Object[] cluste
         throw invalidRequest("Row deletion is not supported by table %s", metadata());
     }
 
-    protected void applyRowUpdate(Object[] partitionKey, @Nullable Object[] clusteringColumns, ColumnMetadata[] columns, Object[] values)
+    protected void applyRowUpdate(Object[] partitionKeys, @Nullable Object[] clusteringKeys, ColumnMetadata[] columns, Object[] values)
     {
         throw invalidRequest("Column modification is not supported by table %s", metadata());
     }
@@ -106,6 +105,7 @@ private void applyRow(Object[] pks, Row row)
                     values[i] = cm.type.compose(cell.value(), cell.accessor());
                 ++i;
             }
+            Invariants.require(i == columns.length);
             applyRowUpdate(pks, cks, columns, values);
         }
     }

src/java/org/apache/cassandra/db/virtual/AbstractMutableLazyVirtualTable.java

@@ -198,8 +198,6 @@ public String toString()
 
     public static class Listener implements CoordinatorEventListener
     {
-        public static final Listener instance = new Listener();
-
         private AccordCoordinatorMetrics forTransaction(TxnId txnId)
         {
             if (txnId != null)

src/java/org/apache/cassandra/db/virtual/AccordDebugKeyspace.java

@@ -112,8 +112,6 @@ public String toString()
 
     public static class Listener implements ReplicaEventListener
     {
-        public static final Listener instance = new Listener();
-
         private AccordReplicaMetrics forTransaction(TxnId txnId)
         {
             if (txnId != null)

src/java/org/apache/cassandra/metrics/AccordCoordinatorMetrics.java

@@ -132,6 +132,10 @@ static class SnapshotBuilder
         }
     }
 
+    public static void touch()
+    {
+    }
+
     private AccordSystemMetrics()
     {
         Invariants.expect(AccordService.isSetup());

src/java/org/apache/cassandra/metrics/AccordReplicaMetrics.java

@@ -41,6 +41,7 @@
 import accord.api.ConfigurationService.EpochReady;
 import accord.primitives.Txn;
 import org.apache.cassandra.metrics.AccordReplicaMetrics;
+import org.apache.cassandra.metrics.AccordSystemMetrics;
 import org.apache.cassandra.service.accord.api.AccordViolationHandler;
 import org.apache.cassandra.utils.Clock;
 import org.apache.cassandra.utils.concurrent.AsyncFuture;
@@ -307,6 +308,7 @@ public synchronized static AccordService startup(NodeId tcmId)
         instance = as;
 
         AccordReplicaMetrics.touch();
+        AccordSystemMetrics.touch();
         AccordViolationHandler.setup();
 
         WatermarkCollector.fetchAndReportWatermarksAsync(as.configService);