PHOENIX-7955 CREATE TABLE IF NOT EXISTS should not mutate existing HBase table properties

Problem:
When CREATE TABLE IF NOT EXISTS was executed against an already-existing table, Phoenix would overwrite the HBase-level table and column family properties (e.g. REGION_REPLICATION, VERSIONS, TTL) with the values from the new DDL statement. This is unexpected - IF NOT EXISTS should be a no-op if the table already exists.

Fix:
In ConnectionQueryServicesImpl changed ensureTableCreated call for TABLE types - passes modifyExistingMetaData = false when the table type is TABLE, so existing properties are not overwritten.

Testing:
Added new test in CreateTableIT which reproduces the problem and verifies the fix.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: PDavid

phoenix-core-client/src/main/java/org/apache/phoenix/query/ConnectionQueryServicesImpl.java

@@ -2550,8 +2550,9 @@ public MetaDataMutationResult createTable(final List<Mutation> tableMetaData,
     ) {
       // For views this will ensure that metadata already exists
       // For tables and indexes, this will create the metadata if it doesn't already exist
+      boolean modifyExistingMetaData = tableType != PTableType.TABLE;
       ensureTableCreated(physicalTableNameBytes, null, tableType, tableProps, families, splits,
-        true, isNamespaceMapped, isDoNotUpgradePropSet);
+        modifyExistingMetaData, isNamespaceMapped, isDoNotUpgradePropSet);
     }
     ImmutableBytesWritable ptr = new ImmutableBytesWritable();
     if (tableType == PTableType.INDEX) { // Index on view

phoenix-core/src/it/java/org/apache/phoenix/end2end/CreateTableIT.java

@@ -25,6 +25,7 @@
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThrows;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
@@ -1769,4 +1770,61 @@ private int checkGuidePostWidth(String tableName) throws Exception {
     }
   }
 
+  @Test
+  public void testCreateTableDoesNotMutateExistingHBaseTableProperties() throws Exception {
+    String tableName = generateUniqueName();
+    Properties props = new Properties();
+
+    // Step 1: Create table with VERSIONS=1 and TTL=86400
+    String createDdl = "CREATE TABLE " + tableName + " (" + " PK VARCHAR NOT NULL PRIMARY KEY,"
+      + " COL1 VARCHAR," + " COL2 INTEGER" + " ) VERSIONS=1, TTL=86400";
+    try (Connection conn = DriverManager.getConnection(getUrl(), props)) {
+      conn.createStatement().execute(createDdl);
+    }
+
+    // Verify initial HBase table properties
+    Admin admin = driver.getConnectionQueryServices(getUrl(), props).getAdmin();
+    TableDescriptor descBefore = admin.getDescriptor(TableName.valueOf(tableName));
+    ColumnFamilyDescriptor[] cfsBefore = descBefore.getColumnFamilies();
+    assertEquals(1, cfsBefore.length);
+    assertEquals(1, cfsBefore[0].getMaxVersions());
+    assertEquals(86400, cfsBefore[0].getTimeToLive());
+
+    // Step 2: Execute CREATE TABLE IF NOT EXISTS with different properties
+    String createIfNotExistsDdl =
+      "CREATE TABLE IF NOT EXISTS " + tableName + " (" + " PK VARCHAR NOT NULL PRIMARY KEY,"
+        + " COL1 VARCHAR," + " COL2 INTEGER" + " ) VERSIONS=5, TTL=120000";
+    try (Connection conn = DriverManager.getConnection(getUrl(), props)) {
+      conn.createStatement().execute(createIfNotExistsDdl);
+    }
+
+    // Step 3: Verify that HBase table properties are NOT changed
+    TableDescriptor descAfter = admin.getDescriptor(TableName.valueOf(tableName));
+    ColumnFamilyDescriptor[] cfsAfter = descAfter.getColumnFamilies();
+    assertEquals(1, cfsAfter.length);
+    assertEquals("VERSIONS should not be modified by IF NOT EXISTS", 1,
+      cfsAfter[0].getMaxVersions());
+    assertEquals("TTL should not be modified by IF NOT EXISTS", 86400, cfsAfter[0].getTimeToLive());
+
+    // Step 4: Execute CREATE TABLE without IF NOT EXISTS with different properties
+    String createWithoutIfNotExistsDdl =
+      "CREATE TABLE " + tableName + " (" + " PK VARCHAR NOT NULL PRIMARY KEY," + " COL1 VARCHAR,"
+        + " COL2 INTEGER" + " ) VERSIONS=6, TTL=120000";
+    try (Connection conn = DriverManager.getConnection(getUrl(), props)) {
+      // Should fail as table exists already.
+      TableAlreadyExistsException exception = assertThrows(TableAlreadyExistsException.class,
+        () -> conn.createStatement().execute(createWithoutIfNotExistsDdl));
+      assertEquals("ERROR 1013 (42M04): Table already exists. tableName=N000063",
+        exception.getMessage());
+    }
+
+    // Step 5: Verify that HBase table properties are still NOT changed
+    TableDescriptor descAfter2 = admin.getDescriptor(TableName.valueOf(tableName));
+    ColumnFamilyDescriptor[] cfsAfter2 = descAfter2.getColumnFamilies();
+    assertEquals(1, cfsAfter2.length);
+    assertEquals("VERSIONS should not be modified for existing table", 1,
+      cfsAfter2[0].getMaxVersions());
+    assertEquals("TTL should not be modified for existing table", 86400,
+      cfsAfter2[0].getTimeToLive());
+  }
 }