Small Benchmarks improvements (#25)

feat: enhance n-ary tree operations and standardize Gatling action names

Add tree traversal methods to NAryTreeBuilder:
- childrenOf(): compute all child node ordinals for a given parent
- siblingsOf(): compute all sibling node ordinals for a given node

Standardize Gatling HTTP action names for consistent reporting:
- "Create XXX" for entity creation
- "Fetch single XXX" for individual entity retrieval  
- "Fetch child XXX" for bulk child entity retrieval
- "Update XXX" for entity updates
- "Check XXX exists" for existence validation

This improves benchmark report readability and provides more tree 
navigation utilities for hierarchical namespace operations.

Author: pingtimeout

benchmarks/src/gatling/scala/org/apache/polaris/benchmarks/NAryTreeBuilder.scala

@@ -47,6 +47,22 @@ case class NAryTreeBuilder(nsWidth: Int, nsDepth: Int) {
       pathToRoot(parent, ordinal :: acc)
     }
 
+  /**
+   * Computes the ordinals of all child nodes for a given node.
+   *
+   * @param ordinal the ordinal of the parent node
+   * @return a list of ordinals representing the child nodes
+   */
+  def childrenOf(ordinal: Int): List[Int] =
+    if (depthOf(ordinal) >= nsDepth - 1) {
+      // Node is a leaf, has no children
+      List.empty
+    } else {
+      // For a node with ordinal p, its children have ordinals: p*nsWidth + 1, p*nsWidth + 2, ..., p*nsWidth + nsWidth
+      val firstChild = ordinal * nsWidth + 1
+      (firstChild until firstChild + nsWidth).toList
+    }
+
   /**
    * Calculates the depth of a node in the n-ary tree based on its ordinal.
    *
@@ -100,4 +116,21 @@ case class NAryTreeBuilder(nsWidth: Int, nsDepth: Int) {
     val lastLevel = nsDepth - 1
     math.pow(nsWidth, lastLevel).toInt
   }
+
+  /**
+   * Computes the ordinals of all sibling nodes for a given node.
+   *
+   * @param ordinal the ordinal of the node
+   * @return a list of ordinals representing the sibling nodes (excluding the node itself)
+   */
+  def siblingsOf(ordinal: Int): List[Int] =
+    if (ordinal == 0) {
+      // Root node has no siblings
+      List.empty
+    } else {
+      // Get parent ordinal
+      val parent = (ordinal - 1) / nsWidth
+      // Get all children of parent (siblings including self) and exclude self
+      childrenOf(parent).filter(_ != ordinal)
+    }
 }

benchmarks/src/gatling/scala/org/apache/polaris/benchmarks/actions/NamespaceActions.scala

@@ -173,7 +173,7 @@ case class NamespaceActions(
    * There is no limit to the number of users that can fetch namespaces concurrently.
    */
   val fetchNamespace: ChainBuilder = exec(
-    http("Fetch Namespace")
+    http("Fetch single namespace")
       .get("/api/catalog/v1/#{catalogName}/namespaces/#{namespaceMultipartPath}")
       .header("Authorization", "Bearer #{accessToken}")
       .check(status.is(200))
@@ -206,15 +206,15 @@ case class NamespaceActions(
    * structure.
    */
   val fetchAllChildrenNamespaces: ChainBuilder = exec(
-    http("Fetch all Namespaces under specific parent")
+    http("Fetch child namespaces")
       .get("/api/catalog/v1/#{catalogName}/namespaces?parent=#{namespaceMultipartPath}")
       .header("Authorization", "Bearer #{accessToken}")
       .check(status.is(200))
   )
 
   val updateNamespaceProperties: ChainBuilder =
-    retryOnHttpStatus(maxRetries, retryableHttpCodes, "Update namespace properties")(
-      http("Update Namespace Properties")
+    retryOnHttpStatus(maxRetries, retryableHttpCodes, "Update namespace")(
+      http("Update namespace")
         .post("/api/catalog/v1/#{catalogName}/namespaces/#{namespaceMultipartPath}/properties")
         .header("Authorization", "Bearer #{accessToken}")
         .header("Content-Type", "application/json")

benchmarks/src/gatling/scala/org/apache/polaris/benchmarks/actions/TableActions.scala

@@ -149,7 +149,7 @@ case class TableActions(
    *
    * There is no limit to the number of users that can create tables concurrently.
    */
-  val createTable: ChainBuilder = retryOnHttpStatus(maxRetries, retryableHttpCodes, "Create table")(
+  val createTable: ChainBuilder = retryOnHttpStatus(maxRetries, retryableHttpCodes, "Create Table")(
     http("Create Table")
       .post("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/tables")
       .header("Authorization", "Bearer #{accessToken}")
@@ -181,7 +181,7 @@ case class TableActions(
    * There is no limit to the number of users that can fetch tables concurrently.
    */
   val fetchTable: ChainBuilder = exec(
-    http("Fetch Table")
+    http("Fetch single Table")
       .get("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/tables/#{tableName}")
       .header("Authorization", "Bearer #{accessToken}")
       .check(status.is(200))
@@ -209,7 +209,7 @@ case class TableActions(
    * given namespace, supporting bulk retrieval of table metadata.
    */
   val fetchAllTables: ChainBuilder = exec(
-    http("Fetch all Tables under parent namespace")
+    http("Fetch children Tables")
       .get("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/tables")
       .header("Authorization", "Bearer #{accessToken}")
       .check(status.is(200))
@@ -222,8 +222,8 @@ case class TableActions(
    * There is no limit to the number of users that can update table properties concurrently.
    */
   val updateTable: ChainBuilder =
-    retryOnHttpStatus(maxRetries, retryableHttpCodes, "Update table metadata")(
-      http("Update table metadata")
+    retryOnHttpStatus(maxRetries, retryableHttpCodes, "Update Table")(
+      http("Update Table")
         .post("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/tables/#{tableName}")
         .header("Authorization", "Bearer #{accessToken}")
         .header("Content-Type", "application/json")

benchmarks/src/gatling/scala/org/apache/polaris/benchmarks/actions/ViewActions.scala

@@ -134,7 +134,7 @@ case class ViewActions(
       )
     }
 
-  val createView: ChainBuilder = retryOnHttpStatus(maxRetries, retryableHttpCodes, "Create view")(
+  val createView: ChainBuilder = retryOnHttpStatus(maxRetries, retryableHttpCodes, "Create View")(
     http("Create View")
       .post("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/views")
       .header("Authorization", "Bearer #{accessToken}")
@@ -171,7 +171,7 @@ case class ViewActions(
   )
 
   val fetchView: ChainBuilder = exec(
-    http("Fetch View")
+    http("Fetch single View")
       .get("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/views/#{viewName}")
       .header("Authorization", "Bearer #{accessToken}")
       .check(status.is(200))
@@ -195,7 +195,7 @@ case class ViewActions(
   )
 
   val fetchAllViews: ChainBuilder = exec(
-    http("Fetch all Views under parent namespace")
+    http("Fetch children Views")
       .get("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/views")
       .header("Authorization", "Bearer #{accessToken}")
       .check(status.is(200))
@@ -208,8 +208,8 @@ case class ViewActions(
    * There is no limit to the number of users that can update table properties concurrently.
    */
   val updateView: ChainBuilder =
-    retryOnHttpStatus(maxRetries, retryableHttpCodes, "Update View metadata")(
-      http("Update View metadata")
+    retryOnHttpStatus(maxRetries, retryableHttpCodes, "Update View")(
+      http("Update View")
         .post("/api/catalog/v1/#{catalogName}/namespaces/#{multipartNamespace}/views/#{viewName}")
         .header("Authorization", "Bearer #{accessToken}")
         .header("Content-Type", "application/json")

benchmarks/src/gatling/scala/org/apache/polaris/benchmarks/simulations/ReadUpdateTreeDataset.scala

@@ -54,7 +54,6 @@ class ReadUpdateTreeDataset extends Simulation {
   // --------------------------------------------------------------------------------
   // Helper values
   // --------------------------------------------------------------------------------
-  private val numNamespaces: Int = dp.nAryTree.numberOfNodes
   private val accessToken: AtomicReference[String] = new AtomicReference()
   private val shouldRefreshToken: AtomicBoolean = new AtomicBoolean(true)
 
@@ -64,6 +63,21 @@ class ReadUpdateTreeDataset extends Simulation {
   private val tblActions = TableActions(dp, wp, accessToken)
   private val viewActions = ViewActions(dp, wp, accessToken)
 
+  private val nsListFeeder = new CircularIterator(nsActions.namespaceIdentityFeeder)
+  private val nsExistsFeeder = new CircularIterator(nsActions.namespaceIdentityFeeder)
+  private val nsFetchFeeder = new CircularIterator(nsActions.namespaceFetchFeeder)
+  private val nsUpdateFeeder = nsActions.namespacePropertiesUpdateFeeder()
+
+  private val tblListFeeder = new CircularIterator(tblActions.tableIdentityFeeder)
+  private val tblExistsFeeder = new CircularIterator(tblActions.tableIdentityFeeder)
+  private val tblFetchFeeder = new CircularIterator(tblActions.tableFetchFeeder)
+  private val tblUpdateFeeder = tblActions.propertyUpdateFeeder()
+
+  private val viewListFeeder = new CircularIterator(viewActions.viewIdentityFeeder)
+  private val viewExistsFeeder = new CircularIterator(viewActions.viewIdentityFeeder)
+  private val viewFetchFeeder = new CircularIterator(viewActions.viewFetchFeeder)
+  private val viewUpdateFeeder = viewActions.propertyUpdateFeeder()
+
   // --------------------------------------------------------------------------------
   // Authentication related workloads:
   // * Authenticate and store the access token for later use every minute
@@ -91,21 +105,6 @@ class ReadUpdateTreeDataset extends Simulation {
         session
       }
 
-  private val nsListFeeder = new CircularIterator(nsActions.namespaceIdentityFeeder)
-  private val nsExistsFeeder = new CircularIterator(nsActions.namespaceIdentityFeeder)
-  private val nsFetchFeeder = new CircularIterator(nsActions.namespaceFetchFeeder)
-  private val nsUpdateFeeder = nsActions.namespacePropertiesUpdateFeeder()
-
-  private val tblListFeeder = new CircularIterator(tblActions.tableIdentityFeeder)
-  private val tblExistsFeeder = new CircularIterator(tblActions.tableIdentityFeeder)
-  private val tblFetchFeeder = new CircularIterator(tblActions.tableFetchFeeder)
-  private val tblUpdateFeeder = tblActions.propertyUpdateFeeder()
-
-  private val viewListFeeder = new CircularIterator(viewActions.viewIdentityFeeder)
-  private val viewExistsFeeder = new CircularIterator(viewActions.viewIdentityFeeder)
-  private val viewFetchFeeder = new CircularIterator(viewActions.viewFetchFeeder)
-  private val viewUpdateFeeder = viewActions.propertyUpdateFeeder()
-
   // --------------------------------------------------------------------------------
   // Workload: Randomly read and write entities
   // --------------------------------------------------------------------------------