diff --git a/online/src/main/scala/ai/chronon/online/fetcher/JoinPartFetcher.scala b/online/src/main/scala/ai/chronon/online/fetcher/JoinPartFetcher.scala
index ba43a89455..53642396ba 100644
--- a/online/src/main/scala/ai/chronon/online/fetcher/JoinPartFetcher.scala
+++ b/online/src/main/scala/ai/chronon/online/fetcher/JoinPartFetcher.scala
@@ -90,7 +90,7 @@ class JoinPartFetcher(fetchContext: FetchContext, metadataStore: MetadataStore)
               val rightKeys = part.leftToRight.map { case (leftKey, rightKey) => rightKey -> request.keys(leftKey) }
               Left(
                 PrefixedRequest(
-                  part.fullPrefix,
+                  part.columnPrefix,
                   Request(part.groupBy.getMetaData.getName, rightKeys, request.atMillis, Some(joinContextInner))))
             }
 
@@ -158,7 +158,7 @@ class JoinPartFetcher(fetchContext: FetchContext, metadataStore: MetadataStore)
     response
       .map { valueMap =>
         if (valueMap != null) {
-          valueMap.map { case (aggName, aggValue) => prefix + "_" + aggName -> aggValue }
+          valueMap.map { case (aggName, aggValue) => prefix + aggName -> aggValue }
         } else {
           Map.empty[String, AnyRef]
         }
@@ -169,7 +169,7 @@ class JoinPartFetcher(fetchContext: FetchContext, metadataStore: MetadataStore)
           if (fetchContext.debug || Math.random() < 0.001) {
             println(s"Failed to fetch $groupByRequest with \n${ex.traceString}")
           }
-          Map(prefix + "_exception" -> ex.traceString)
+          Map(prefix + "exception" -> ex.traceString)
       }
       .get
   }
diff --git a/online/src/test/scala/ai/chronon/online/test/FetcherBaseTest.scala b/online/src/test/scala/ai/chronon/online/test/FetcherBaseTest.scala
index 7ed57ec270..a86f63588a 100644
--- a/online/src/test/scala/ai/chronon/online/test/FetcherBaseTest.scala
+++ b/online/src/test/scala/ai/chronon/online/test/FetcherBaseTest.scala
@@ -211,7 +211,7 @@ class FetcherBaseTest extends AnyFlatSpec with MockitoSugar with Matchers with M
         ))
     )
 
-    val result = baseFetcher.parseGroupByResponse("prefix", request, response)
+    val result = baseFetcher.parseGroupByResponse("prefix_", request, response)
     assertEquals(result, Map("prefix_key" -> "value"))
   }
 
@@ -227,7 +227,7 @@ class FetcherBaseTest extends AnyFlatSpec with MockitoSugar with Matchers with M
         ))
     )
 
-    val result = baseFetcher.parseGroupByResponse("prefix", request, response)
+    val result = baseFetcher.parseGroupByResponse("prefix_", request, response)
     result shouldBe Map()
   }
 
@@ -243,7 +243,7 @@ class FetcherBaseTest extends AnyFlatSpec with MockitoSugar with Matchers with M
         ))
     )
 
-    val result = baseFetcher.parseGroupByResponse("prefix", request, response)
+    val result = baseFetcher.parseGroupByResponse("prefix_", request, response)
     result.keySet shouldBe Set("prefix_exception")
   }
 
diff --git a/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherFailureTest.scala b/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherFailureTest.scala
index 01c432fdea..f3adeee77b 100644
--- a/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherFailureTest.scala
+++ b/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherFailureTest.scala
@@ -80,7 +80,7 @@ class FetcherFailureTest extends AnyFlatSpec {
     val request = Request(joinConf.metaData.name, keyMap)
     val (responses, _) = FetcherTestUtil.joinResponses(spark, Array(request), mockApi)
     val responseMap = responses.head.values.get
-    val exceptionKeys = joinConf.joinPartOps.map(jp => jp.fullPrefix + "_exception")
+    val exceptionKeys = joinConf.joinPartOps.map(jp => jp.columnPrefix + "exception")
     exceptionKeys.foreach(k => assertTrue(responseMap.contains(k)))
   }
 
diff --git a/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTest.scala b/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTest.scala
index b42c868d12..53154dae01 100644
--- a/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTest.scala
+++ b/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTest.scala
@@ -102,8 +102,11 @@ class FetcherTest extends AnyFlatSpec {
       tableUtils.sql(
         s"SELECT * FROM $joinTable WHERE ts >= unix_timestamp('$endDs', '${tableUtils.partitionSpec.format}')")
     }
-    val endDsQueries = endDsEvents.drop(endDsEvents.schema.fieldNames.filter(_.contains("unit_test")): _*)
+    // Keep only left-side columns (keys, ts, ds) and drop all feature columns
     val keys = joinConf.leftKeyCols
+    val leftSideColumns = keys ++ Array(Constants.TimeColumn, tableUtils.partitionColumn)
+    val columnsToKeep = endDsEvents.schema.fieldNames.filter(leftSideColumns.contains)
+    val endDsQueries = endDsEvents.select(columnsToKeep.map(col): _*)
     val keyIndices = keys.map(endDsQueries.schema.fieldIndex)
     val tsIndex = endDsQueries.schema.fieldIndex(Constants.TimeColumn)
     val metadataStore = new fetcher.MetadataStore(FetchContext(inMemoryKvStore))
diff --git a/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTestUtil.scala b/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTestUtil.scala
index ccf26b43b6..a0f02054fb 100644
--- a/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTestUtil.scala
+++ b/spark/src/test/scala/ai/chronon/spark/test/fetcher/FetcherTestUtil.scala
@@ -440,29 +440,35 @@ object FetcherTestUtil {
     queriesDf.show()
     queriesDf.save(queriesTable)
 
-    val joinConf = Builders.Join(
-      left = Builders.Source.events(Builders.Query(startPartition = today), table = queriesTable),
-      joinParts = Seq(
-        Builders.JoinPart(groupBy = vendorRatingsGroupBy, keyMapping = Map("vendor_id" -> "vendor")),
-        Builders.JoinPart(groupBy = userPaymentsGroupBy, keyMapping = Map("user_id" -> "user")),
-        Builders.JoinPart(groupBy = userBalanceGroupBy, keyMapping = Map("user_id" -> "user")),
-        Builders.JoinPart(groupBy = reviewGroupBy),
-        Builders.JoinPart(groupBy = creditGroupBy, prefix = "b"),
-        Builders.JoinPart(groupBy = creditGroupBy, prefix = "a"),
-        Builders.JoinPart(groupBy = creditDerivationGroupBy, prefix = "c")
-      ),
-      metaData = Builders.MetaData(name = "test.payments_join",
-                                   namespace = namespace,
-                                   team = "chronon",
-                                   consistencySamplePercent = 30),
-      derivations = Seq(
-        Builders.Derivation("*", "*"),
-        Builders.Derivation("hist_3d", "unit_test_vendor_ratings_txn_types_histogram_3d"),
-        Builders.Derivation("payment_variance", "unit_test_user_payments_payment_variance/2"),
-        Builders.Derivation("derived_ds", "from_unixtime(ts/1000, 'yyyy-MM-dd')"),
-        Builders.Derivation("direct_ds", "ds")
+    val joinConf = Builders
+      .Join(
+        left = Builders.Source.events(Builders.Query(startPartition = today), table = queriesTable),
+        joinParts = Seq(
+          Builders
+            .JoinPart(groupBy = vendorRatingsGroupBy, keyMapping = Map("vendor_id" -> "vendor"))
+            .setUseLongNames(false),
+          Builders
+            .JoinPart(groupBy = userPaymentsGroupBy, keyMapping = Map("user_id" -> "user"))
+            .setUseLongNames(false),
+          Builders.JoinPart(groupBy = userBalanceGroupBy, keyMapping = Map("user_id" -> "user")).setUseLongNames(false),
+          Builders.JoinPart(groupBy = reviewGroupBy).setUseLongNames(false),
+          Builders.JoinPart(groupBy = creditGroupBy, prefix = "b").setUseLongNames(false),
+          Builders.JoinPart(groupBy = creditGroupBy, prefix = "a").setUseLongNames(false),
+          Builders.JoinPart(groupBy = creditDerivationGroupBy, prefix = "c").setUseLongNames(false)
+        ),
+        metaData = Builders.MetaData(name = "test.payments_join",
+                                     namespace = namespace,
+                                     team = "chronon",
+                                     consistencySamplePercent = 30),
+        derivations = Seq(
+          Builders.Derivation("*", "*"),
+          Builders.Derivation("hist_3d", "vendor_txn_types_histogram_3d"),
+          Builders.Derivation("payment_variance", "user_payment_variance/2"),
+          Builders.Derivation("derived_ds", "from_unixtime(ts/1000, 'yyyy-MM-dd')"),
+          Builders.Derivation("direct_ds", "ds")
+        )
       )
-    )
+      .setUseLongNames(false)
     joinConf
   }