PHOENIX-7524: Fix IndexOutOfBoundsException in queries with OFFSET when rows are exhausted

phoenix-core-server/src/main/java/org/apache/phoenix/iterate/NonAggregateRegionScannerFactory.java

@@ -83,6 +83,7 @@
 import org.apache.phoenix.util.EncodedColumnsUtil;
 import org.apache.phoenix.util.IndexUtil;
 import org.apache.phoenix.util.ScanUtil;
+import org.apache.phoenix.util.ServerUtil;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -493,7 +494,16 @@ public boolean next(List<Cell> results, ScannerContext scannerContext) throws IO
                 kv = new KeyValue(QueryConstants.OFFSET_ROW_KEY_BYTES, QueryConstants.OFFSET_FAMILY,
                   QueryConstants.OFFSET_COLUMN, remainingOffset);
               } else {
-                kv = getOffsetKvWithLastScannedRowKey(remainingOffset, tuple);
+                // Check if tuple is empty before calling getOffsetKvWithLastScannedRowKey
+                // to avoid IndexOutOfBoundsException when accessing tuple.getKey()
+                if (tuple.size() > 0) {
+                  kv = getOffsetKvWithLastScannedRowKey(remainingOffset, tuple);
+                } else {
+                  // Use fallback logic when tuple is empty (PHOENIX-7524)
+                  byte[] rowKey = ServerUtil.deriveRowKeyFromScanOrRegionBoundaries(scan, region);
+                  kv = new KeyValue(rowKey, QueryConstants.OFFSET_FAMILY,
+                    QueryConstants.OFFSET_COLUMN, remainingOffset);
+                }
               }
               results.add(kv);
             } else {

phoenix-core-server/src/main/java/org/apache/phoenix/util/ServerUtil.java

@@ -291,4 +291,33 @@ public static <T> Throwable getExceptionFromFailedFuture(Future<T> f) {
     }
     return t;
   }
+
+  /**
+   * Derives a safe row key for empty result sets based on scan or region boundaries. Used when
+   * constructing KeyValues for aggregate results or OFFSET responses when no actual data rows were
+   * scanned.
+   * @param scan   The scan being executed
+   * @param region The region being scanned
+   * @return A valid row key derived from scan or region boundaries
+   */
+  public static byte[] deriveRowKeyFromScanOrRegionBoundaries(Scan scan, Region region) {
+    byte[] startKey =
+      scan.getStartRow().length > 0 ? scan.getStartRow() : region.getRegionInfo().getStartKey();
+    byte[] endKey =
+      scan.getStopRow().length > 0 ? scan.getStopRow() : region.getRegionInfo().getEndKey();
+
+    byte[] rowKey = ByteUtil.getLargestPossibleRowKeyInRange(startKey, endKey);
+
+    if (rowKey == null) {
+      if (scan.includeStartRow()) {
+        rowKey = startKey;
+      } else if (scan.includeStopRow()) {
+        rowKey = endKey;
+      } else {
+        rowKey = HConstants.EMPTY_END_ROW;
+      }
+    }
+
+    return rowKey;
+  }
 }

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

@@ -987,6 +987,49 @@ public void testCDCIndexTTLEqualsToMaxLookbackAge() throws Exception {
     }
   }
 
+  /**
+   * Test for PHOENIX-7524: CDC Query with OFFSET can throw IndexOutOfBoundsException Scenario: CDC
+   * query with OFFSET that exceeds available rows Expected: Query should return empty result set
+   */
+  @Test
+  public void testCDCQueryWithOffsetExceedingRows() throws Exception {
+    String schemaName = getSchemaName();
+    String tableName = getTableOrViewName(schemaName);
+    String cdcName = getCDCName();
+
+    try (Connection conn = newConnection()) {
+      // Multi-tenant tables require at least 2 PK columns (tenant_id, other_pk)
+      String createTableDDL = multitenant
+        ? "CREATE TABLE " + tableName
+          + " (tenant_id VARCHAR NOT NULL, k VARCHAR NOT NULL, v1 INTEGER, v2 INTEGER "
+          + "CONSTRAINT pk PRIMARY KEY (tenant_id, k))"
+        : "CREATE TABLE " + tableName + " (k VARCHAR NOT NULL PRIMARY KEY, v1 INTEGER, v2 INTEGER)";
+
+      createTable(conn, createTableDDL, encodingScheme, multitenant, tableSaltBuckets, false, null);
+      createCDC(conn, "CREATE CDC " + cdcName + " ON " + tableName, encodingScheme);
+
+      String upsertSQL = multitenant
+        ? "UPSERT INTO " + tableName + " VALUES ('tenant1', 'a', 1, 2)"
+        : "UPSERT INTO " + tableName + " VALUES ('a', 1, 2)";
+      conn.createStatement().executeUpdate(upsertSQL);
+      conn.commit();
+
+      // This query should return empty result, not throw exception
+      // OFFSET 1 with only 1 row means we skip the only row
+      // IMPORTANT: Using PHOENIX_ROW_TIMESTAMP() > CURRENT_TIME() without subtraction
+      // This means the WHERE clause filters out ALL rows (no row has timestamp in the future)
+      // So we're trying to OFFSET past 0 rows
+      String cdcFullName = SchemaUtil.getTableName(schemaName, cdcName);
+      String query = "SELECT * FROM " + cdcFullName
+        + " WHERE PHOENIX_ROW_TIMESTAMP() > CURRENT_TIME() LIMIT 1 OFFSET 1";
+
+      ResultSet rs = conn.createStatement().executeQuery(query);
+
+      // Should return no rows without throwing exception
+      assertFalse("Expected no rows when OFFSET exceeds available data", rs.next());
+    }
+  }
+
   private String getSchemaName() {
     return withSchemaName
       ? caseSensitiveNames

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

@@ -231,6 +231,143 @@ public void testMetaDataWithOffset() throws SQLException {
     assertEquals(5, md.getColumnCount());
   }
 
+  /**
+   * Test for PHOENIX-7524: Query with WHERE clause that filters all rows + OFFSET Scenario: WHERE
+   * clause filters out all rows, then OFFSET tries to skip rows Expected: Query should return empty
+   * result set
+   */
+  @Test
+  public void testOffsetWithWhereClauseFilteringAllRows() throws SQLException {
+    String testTableName = generateUniqueName();
+    Connection conn =
+      DriverManager.getConnection(getUrl(), PropertiesUtil.deepCopy(TEST_PROPERTIES));
+
+    conn.createStatement().execute(
+      "CREATE TABLE " + testTableName + " (id INTEGER NOT NULL PRIMARY KEY, name VARCHAR)");
+
+    for (int i = 1; i <= 10; i++) {
+      conn.createStatement()
+        .executeUpdate("UPSERT INTO " + testTableName + " VALUES (" + i + ", 'name" + i + "')");
+    }
+    conn.commit();
+
+    // WHERE clause that filters ALL rows (no row has id > 100)
+    String query = "SELECT * FROM " + testTableName + " WHERE id > 100 LIMIT 5 OFFSET 1";
+    ResultSet rs = conn.createStatement().executeQuery(query);
+
+    // Should return no rows without throwing exception
+    assertFalse("Expected no rows when WHERE filters all rows", rs.next());
+    conn.close();
+  }
+
+  /**
+   * Test for PHOENIX-7524: Empty table with OFFSET Scenario: Table exists but has no rows Expected:
+   * Query should return empty result set
+   */
+  @Test
+  public void testOffsetOnEmptyTable() throws SQLException {
+    String testTableName = generateUniqueName();
+    Connection conn =
+      DriverManager.getConnection(getUrl(), PropertiesUtil.deepCopy(TEST_PROPERTIES));
+
+    conn.createStatement()
+      .execute("CREATE TABLE " + testTableName + " (id INTEGER NOT NULL PRIMARY KEY, val VARCHAR)");
+    // Don't insert any rows - table is empty
+    conn.commit();
+
+    // Query empty table with OFFSET
+    String query = "SELECT * FROM " + testTableName + " LIMIT 10 OFFSET 5";
+    ResultSet rs = conn.createStatement().executeQuery(query);
+
+    assertFalse("Expected no rows from empty table", rs.next());
+    conn.close();
+  }
+
+  /**
+   * Test for PHOENIX-7524: OFFSET with LIKE pattern matching nothing Scenario: LIKE pattern that
+   * doesn't match any rows Expected: Query should return empty result set
+   */
+  @Test
+  public void testOffsetWithLikePatternMatchingNothing() throws SQLException {
+    String testTableName = generateUniqueName();
+    Connection conn =
+      DriverManager.getConnection(getUrl(), PropertiesUtil.deepCopy(TEST_PROPERTIES));
+
+    conn.createStatement().execute(
+      "CREATE TABLE " + testTableName + " (name VARCHAR NOT NULL PRIMARY KEY, score INTEGER)");
+
+    conn.createStatement().executeUpdate("UPSERT INTO " + testTableName + " VALUES ('test1', 100)");
+    conn.createStatement().executeUpdate("UPSERT INTO " + testTableName + " VALUES ('test2', 200)");
+    conn.createStatement().executeUpdate("UPSERT INTO " + testTableName + " VALUES ('test3', 300)");
+    conn.commit();
+
+    // LIKE pattern that doesn't match
+    String query = "SELECT * FROM " + testTableName + " WHERE name LIKE 'prod%' LIMIT 10 OFFSET 2";
+    ResultSet rs = conn.createStatement().executeQuery(query);
+
+    assertFalse("Expected no rows with LIKE pattern matching nothing", rs.next());
+    conn.close();
+  }
+
+  /**
+   * Test for PHOENIX-7524: OFFSET on table with splits but empty regions Scenario: Pre-split table
+   * with no data in certain regions Expected: Query should return empty result set
+   */
+  @Test
+  public void testOffsetOnSplitTableWithEmptyRegions() throws SQLException {
+    String testTableName = generateUniqueName();
+    Connection conn =
+      DriverManager.getConnection(getUrl(), PropertiesUtil.deepCopy(TEST_PROPERTIES));
+
+    // Create pre-split table
+    conn.createStatement().execute("CREATE TABLE " + testTableName
+      + " (pk VARCHAR NOT NULL PRIMARY KEY, data INTEGER) SPLIT ON ('m', 'z')");
+
+    // Insert data only in first region (before 'm')
+    conn.createStatement().executeUpdate("UPSERT INTO " + testTableName + " VALUES ('a', 1)");
+    conn.createStatement().executeUpdate("UPSERT INTO " + testTableName + " VALUES ('b', 2)");
+    conn.commit();
+
+    // Query range 'n' to 'y' (in middle/last region with no data)
+    String query =
+      "SELECT * FROM " + testTableName + " WHERE pk >= 'n' AND pk < 'y' LIMIT 5 OFFSET 1";
+    ResultSet rs = conn.createStatement().executeQuery(query);
+
+    assertFalse("Expected no rows in empty region", rs.next());
+    conn.close();
+  }
+
+  /**
+   * Test for PHOENIX-7524: OFFSET exceeds rows returned by WHERE clause Scenario: WHERE clause
+   * returns SOME rows (e.g., 5 rows), but OFFSET exceeds them (e.g., 10) Expected: Query should
+   * return empty result set
+   */
+  @Test
+  public void testOffsetExceedsRowsReturnedByWhereClause() throws SQLException {
+    String testTableName = generateUniqueName();
+    Connection conn =
+      DriverManager.getConnection(getUrl(), PropertiesUtil.deepCopy(TEST_PROPERTIES));
+
+    conn.createStatement().execute("CREATE TABLE " + testTableName
+      + " (id INTEGER NOT NULL PRIMARY KEY, category VARCHAR, val INTEGER)");
+
+    for (int i = 1; i <= 20; i++) {
+      conn.createStatement().executeUpdate("UPSERT INTO " + testTableName + " VALUES (" + i
+        + ", 'cat" + (i % 3) + "', " + (i * 100) + ")");
+    }
+    conn.commit();
+
+    // WHERE clause returns 7 rows (id <= 20 where id % 3 == 1: rows 1,4,7,10,13,16,19)
+    // But OFFSET is 10, which exceeds the 7 rows available
+    String query = "SELECT * FROM " + testTableName + " WHERE category = 'cat1' LIMIT 5 OFFSET 10";
+    ResultSet rs = conn.createStatement().executeQuery(query);
+
+    // Should return no rows without throwing exception
+    assertFalse("Expected no rows when OFFSET exceeds filtered result count", rs.next());
+
+    conn.close();
+  }
+
   private void initTableValues(Connection conn) throws SQLException {
     for (int i = 0; i < 26; i++) {
       conn.createStatement().execute("UPSERT INTO " + tableName + " values('" + STRINGS[i] + "',"