Diveyam-Mishra commented on code in PR #5048:
URL: https://github.com/apache/calcite/pull/5048#discussion_r3556880820
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file/src/test/java/org/apache/calcite/adapter/file/FileAdapterTest.java:
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@@ -417,6 +418,173 @@ private static void checkEmpty(ResultSet resultSet) {
sql("model-with-custom-table", sql).ok();
}
+ /** Test case for
+ * <a
href="https://issues.apache.org/jira/browse/CALCITE-7618";>[CALCITE-7618]
+ * Add filter pushdown support to file adapter's CSV implementation</a>.
+ *
+ * <p>Verifies that a simple equality filter is pushed into {@link
CsvTableScan},
+ * eliminating the {@code EnumerableCalc} that would otherwise evaluate it.
*/
+ @Test void testFilterPushDown() {
+ final String sql = "explain plan for select * from EMPS where deptno = 20";
+ final String expected = "PLAN=CsvTableScan(table=[[SALES, EMPS]], "
+ + "fields=[[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]], condition=[=($2, 20)])\n";
+ sql("smart", sql).returns(expected).ok();
+ }
+
+ @Test void testFilterPushDownWithProject() {
+ final String sql = "explain plan for select name, empno from EMPS where
deptno = 20";
+ final String expected = "PLAN=EnumerableCalc(expr#0..2=[{inputs}],"
Review Comment:
Yes, the filter is pushed into CsvTableScan by
CsvProjectFilterTableScanRule. During CsvTableScan.implement(), the scan
compiles its stored condition into an EnumerableCalc over a condition-less
scan, which is why the generated plan displays $condition in the calc. The
predicate is still owned by the scan before implementation and is evaluated
once through the generated calc code.
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