godfreyhe commented on a change in pull request #12866:
URL: https://github.com/apache/flink/pull/12866#discussion_r455672711
##########
File path:
flink-table/flink-table-planner-blink/src/test/java/org/apache/flink/table/planner/factories/TestValuesTableFactory.java
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@@ -448,6 +478,127 @@ public void applyProjection(int[][] projectedFields) {
this.projectedFields =
Arrays.stream(projectedFields).mapToInt(f -> f[0]).toArray();
}
+ @Override
+ public Result applyFilters(List<ResolvedExpression> filters) {
+ List<ResolvedExpression> acceptedFilters = new
ArrayList<>();
+ List<ResolvedExpression> remainingFilters = new
ArrayList<>();
+ for (ResolvedExpression expr : filters) {
+ if (shouldPushDown(expr)) {
+ acceptedFilters.add(expr);
+ } else {
+ remainingFilters.add(expr);
+ }
+ }
+ this.filterPredicates = acceptedFilters;
+ return Result.of(acceptedFilters, remainingFilters);
+ }
+
+ private boolean shouldPushDown(Expression expr) {
+ if (expr instanceof CallExpression &&
expr.getChildren().size() == 2) {
+ return
shouldPushDownUnaryExpression(expr.getChildren().get(0))
+ &&
shouldPushDownUnaryExpression(expr.getChildren().get(1));
+ }
+ return false;
+ }
+
+ private boolean shouldPushDownUnaryExpression(Expression expr) {
+ if (expr instanceof FieldReferenceExpression) {
+ if
(filterableFields.contains(((FieldReferenceExpression) expr).getName())) {
+ return true;
+ }
+ }
+
+ if (expr instanceof ValueLiteralExpression) {
+ // validate that literal is comparable
+ Optional value = ((ValueLiteralExpression)
expr).getValueAs(((ValueLiteralExpression)
expr).getOutputDataType().getConversionClass());
Review comment:
we should also consider whether the type of `FieldReferenceExpression `
is comparable, consider the following pattern:
the `filterableFields` is `a` and `b` and the pushed pattern `a > b`
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