fix IT due to performance change

Signed-off-by: xinyual <xinyual@amazon.com>

Author: xinyual

docs/user/ppl/cmd/appendpipe.rst

@@ -66,23 +66,7 @@ PPL query::
     | 101      | M      | null  |
     +----------+--------+-------+
 
-Example 3: Append rows with column type conflict
-=============================================
-
-This example shows how column type conflicts are handled when appending results. Same name columns with different types will generate two different columns in appended result.
-
-PPL query::
-
-    os> source=accounts | stats sum(age) as total by gender, state | sort -total | head 5 | appendpipe [ stats sum(total) as total by gender | eval state = 123 ];
-    fetched rows / total rows = 6/6
-    +------+--------+-------+--------+
-    | sum  | gender | state | state0 |
-    |------+--------+-------+--------|
-    | 36   | M      | TN    | null   |
-    | 33   | M      | MD    | null   |
-    | 32   | M      | IL    | null   |
-    | 28   | F      | VA    | null   |
-    | 28   | F      | null  | 123    |
-    | 101  | M      | null  | 123    |
-    +------+--------+-------+--------+
+Limitations
+===========
 
+* **Schema Compatibility**: Same as command ``append``, when fields with the same name exist between the main search and sub-search but have incompatible types, the query will fail with an error. To avoid type conflicts, ensure that fields with the same name have the same data type, or use different field names (e.g., by renaming with ``eval`` or using ``fields`` to select non-conflicting columns).

integ-test/src/test/java/org/opensearch/sql/calcite/remote/CalcitePPLAppendPipeCommandIT.java

@@ -75,20 +75,16 @@ public void testAppendpipeWithMergedColumn() throws IOException {
 
   @Test
   public void testAppendpipeWithConflictTypeColumn() throws IOException {
-    JSONObject actual =
-        executeQuery(
-            String.format(
-                Locale.ROOT,
-                "source=%s | stats sum(age) as sum by gender | appendpipe [ eval sum = cast(sum as"
-                    + " double) ] | head 5",
-                TEST_INDEX_ACCOUNT));
-    verifySchemaInOrder(
-        actual, schema("sum", "bigint"), schema("gender", "string"), schema("sum0", "double"));
-    verifyDataRows(
-        actual,
-        rows(14947, "F", null),
-        rows(15224, "M", null),
-        rows(null, "F", 14947d),
-        rows(null, "M", 15224d));
+    Exception exception =
+        assertThrows(
+            Exception.class,
+            () ->
+                executeQuery(
+                    String.format(
+                        Locale.ROOT,
+                        "source=%s | stats sum(age) as sum by gender | appendpipe [ eval sum ="
+                            + " cast(sum as double) ] | head 5",
+                        TEST_INDEX_ACCOUNT)));
+    assertTrue(exception.getMessage().contains("due to incompatible types"));
   }
 }

ppl/src/test/java/org/opensearch/sql/ppl/calcite/CalcitePPLAppendPipeTest.java

@@ -59,26 +59,4 @@ public void testAppendPipeWithMergedColumns() {
             + "FROM `scott`.`EMP`";
     verifyPPLToSparkSQL(root, expectedSparkSql);
   }
-
-  @Test
-  public void testAppendPipeWithConflictTypeColumn() {
-    String ppl = "source=EMP | fields DEPTNO | appendpipe [ | fields DEPTNO | eval DEPTNO = 20 ]";
-    RelNode root = getRelNode(ppl);
-    String expectedLogical =
-        "LogicalUnion(all=[true])\n"
-            + "  LogicalProject(DEPTNO=[$7], DEPTNO0=[null:INTEGER])\n"
-            + "    LogicalTableScan(table=[[scott, EMP]])\n"
-            + "  LogicalProject(DEPTNO=[null:TINYINT], DEPTNO0=[20])\n"
-            + "    LogicalTableScan(table=[[scott, EMP]])\n";
-    verifyLogical(root, expectedLogical);
-    verifyResultCount(root, 28);
-
-    String expectedSparkSql =
-        "SELECT `DEPTNO`, CAST(NULL AS INTEGER) `DEPTNO0`\n"
-            + "FROM `scott`.`EMP`\n"
-            + "UNION ALL\n"
-            + "SELECT CAST(NULL AS TINYINT) `DEPTNO`, 20 `DEPTNO0`\n"
-            + "FROM `scott`.`EMP`";
-    verifyPPLToSparkSQL(root, expectedSparkSql);
-  }
 }