Fix BasicLoadBalancingPolicy.getReplica empty partitioner (#503)

dkropachev · web-flow · commit eb3f5d0e4237 · 2025-04-07T07:39:33.000-04:00
Queries getting paritioner set either from user, or when statement is being built against cdc tablet. In other cases statement does not get any partitioner. For proper tablet routing driver needs to calculate token from the key, which needs partitioner, if partitioner is not present driver returns empty replica list. This fix is rather quick-fix. Implementing proper solution that will help with CDC+tablets case, is scheduled at #502
diff --git a/core/src/main/java/com/datastax/oss/driver/api/core/metadata/TokenMap.java b/core/src/main/java/com/datastax/oss/driver/api/core/metadata/TokenMap.java
@@ -189,4 +189,8 @@ default Set<Node> getReplicas(@NonNull String keyspaceName, @NonNull TokenRange
   /** The name of the partitioner class in use, as reported by the Cassandra nodes. */
   @NonNull
   String getPartitionerName();
+
+  /** The partitioner class in use, as reported by the Cassandra nodes. */
+  @NonNull
+  Partitioner getPartitioner();
 }
diff --git a/core/src/main/java/com/datastax/oss/driver/internal/core/loadbalancing/BasicLoadBalancingPolicy.java b/core/src/main/java/com/datastax/oss/driver/internal/core/loadbalancing/BasicLoadBalancingPolicy.java
@@ -333,6 +333,9 @@ protected Set<Node> getReplicas(@Nullable Request request, @Nullable Session ses
       }
 
       partitioner = request.getPartitioner();
+      if (partitioner == null && maybeTokenMap.isPresent()) {
+        partitioner = maybeTokenMap.get().getPartitioner();
+      }
     } catch (Exception e) {
       // Protect against poorly-implemented Request instances
       LOG.error("Unexpected error while trying to compute query plan", e);
diff --git a/core/src/main/java/com/datastax/oss/driver/internal/core/metadata/token/DefaultTokenMap.java b/core/src/main/java/com/datastax/oss/driver/internal/core/metadata/token/DefaultTokenMap.java
@@ -207,6 +207,12 @@ public String getPartitionerName() {
     return tokenFactory.getPartitionerName();
   }
 
+  @NonNull
+  @Override
+  public Partitioner getPartitioner() {
+    return tokenFactory;
+  }
+
   private KeyspaceTokenMap getKeyspaceMap(CqlIdentifier keyspace) {
     Map<String, String> config = replicationConfigs.get(keyspace);
     return (config == null) ? null : keyspaceMaps.get(config);

Original file line number	Diff line number	Diff line change
`@@ -189,4 +189,8 @@ default Set<Node> getReplicas(@NonNull String keyspaceName, @NonNull TokenRange`
`189`	`189`	`/** The name of the partitioner class in use, as reported by the Cassandra nodes. */`
`190`	`190`	`@NonNull`
`191`	`191`	`String getPartitionerName();`
	`192`	`+`
	`193`	`+ /** The partitioner class in use, as reported by the Cassandra nodes. */`
	`194`	`+ @NonNull`
	`195`	`+ Partitioner getPartitioner();`
`192`	`196`	`}`
Original file line number	Diff line number	Diff line change
`@@ -333,6 +333,9 @@ protected Set<Node> getReplicas(@Nullable Request request, @Nullable Session ses`
`333`	`333`	`}`
`334`	`334`
`335`	`335`	`partitioner = request.getPartitioner();`
	`336`	`+ if (partitioner == null && maybeTokenMap.isPresent()) {`
	`337`	`+ partitioner = maybeTokenMap.get().getPartitioner();`
	`338`	`+ }`
`336`	`339`	`} catch (Exception e) {`
`337`	`340`	`// Protect against poorly-implemented Request instances`
`338`	`341`	`LOG.error("Unexpected error while trying to compute query plan", e);`