PHOENIX-7948 IndexTwoPhaseCreateIT requests an illegal transform

The test creates a mutable base table and then asserts that a transform
to SINGLE_CELL_ARRAY_WITH_OFFSETS produces a new physical table with that
storage scheme. SINGLE_CELL_ARRAY_WITH_OFFSETS is incompatible with
in-place mutation, so Phoenix intentionally downgrades the requested
scheme to ONE_CELL_PER_COLUMN for any mutable base table.

Co-authored-by: Claude Opus 4.8[1m] <noreply@anthropic.com>

Author: apurtell

phoenix-core/src/it/java/org/apache/phoenix/end2end/index/IndexTwoPhaseCreateIT.java

@@ -35,6 +35,7 @@
 import java.util.Properties;
 import org.apache.phoenix.coprocessorclient.BaseScannerRegionObserverConstants;
 import org.apache.phoenix.end2end.IndexToolIT;
+import org.apache.phoenix.end2end.NeedsOwnMiniClusterTest;
 import org.apache.phoenix.end2end.transform.TransformToolIT;
 import org.apache.phoenix.jdbc.PhoenixConnection;
 import org.apache.phoenix.query.BaseTest;
@@ -50,9 +51,11 @@
 import org.junit.AfterClass;
 import org.junit.BeforeClass;
 import org.junit.Test;
+import org.junit.experimental.categories.Category;
 
 import org.apache.phoenix.thirdparty.com.google.common.collect.Maps;
 
+@Category(NeedsOwnMiniClusterTest.class)
 public class IndexTwoPhaseCreateIT extends BaseTest {
   @BeforeClass
   public static synchronized void doSetup() throws Exception {
@@ -131,9 +134,12 @@ public void testTransformingTableAndIndex() throws Exception {
       String tableName = "TBL_" + generateUniqueName();
       String idxName = "IND_" + generateUniqueName();
 
+      // The table must be immutable: SINGLE_CELL_ARRAY_WITH_OFFSETS packs all of a row's
+      // columns into a single cell, which is incompatible with in-place mutation.
       String createTableSql =
         "CREATE TABLE " + tableName + " (PK1 VARCHAR NOT NULL, INT_PK INTEGER NOT NULL, "
-          + "V1 VARCHAR, V2 INTEGER CONSTRAINT NAME_PK PRIMARY KEY(PK1, INT_PK)) ";
+          + "V1 VARCHAR, V2 INTEGER CONSTRAINT NAME_PK PRIMARY KEY(PK1, INT_PK)) "
+          + "IMMUTABLE_ROWS=true";
       conn.createStatement().execute(createTableSql);
 
       String upsertStmt =