rdblue commented on code in PR #5872:
URL: https://github.com/apache/iceberg/pull/5872#discussion_r990820290
##########
spark/v3.3/spark/src/main/java/org/apache/iceberg/spark/source/SparkScanBuilder.java:
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@@ -145,6 +158,83 @@ public Filter[] pushedFilters() {
return pushedFilters;
}
+ @Override
+ public boolean pushAggregation(Aggregation aggregation) {
+ if (!(table instanceof BaseTable)) {
+ return false;
+ }
+ boolean aggregatePushdown =
+ Boolean.parseBoolean(
+ table
+ .properties()
+ .getOrDefault(AGGREGATE_PUSHDOWN_ENABLED,
AGGREGATE_PUSHDOWN_ENABLED_DEFAULT));
+ if (!aggregatePushdown) {
+ return false;
+ }
+
+ Snapshot currentSnapshot = table.currentSnapshot();
+ if (currentSnapshot != null) {
+ Map<String, String> map = currentSnapshot.summary();
+ // if there are row-level deletes in current snapshot, the statics
+ // maybe changed, so disable push down aggregate
+ if (Integer.parseInt(map.get("total-position-deletes")) > 0
+ || Integer.parseInt(map.get("total-equality-deletes")) > 0) {
+ return false;
+ }
+ }
+
+ // If the group by expression is not the same as the partition, the
statistics information
+ // in manifest files cannot be used to calculate min/max/count. However,
if the
+ // group by expression is not the same as the partition, the statistics
information can still
+ // be used to calculate min/max/count.
+ // Todo: enable aggregate push down for partition col group by expression
+ if (aggregation.groupByExpressions().length > 0) {
+ return false;
+ }
+
+ List<Expression> expressions =
+
Lists.newArrayListWithExpectedSize(aggregation.aggregateExpressions().length);
+ List<AggregateFunc> pushed =
+
Lists.newArrayListWithExpectedSize(aggregation.aggregateExpressions().length);
+ for (AggregateFunc aggregate : aggregation.aggregateExpressions()) {
+ Expression expr = SparkAggregates.convert(aggregate);
+ if (expr != null) {
+ try {
+ Binder.bind(schema.asStruct(), expr, caseSensitive);
+ expressions.add(expr);
+ pushed.add(aggregate);
+ } catch (ValidationException e) {
+ // binding to the table schema failed, so this expression cannot be
pushed down
+ // disable aggregate push down
+ LOG.info(
+ "Failed to bind expression to table schema, can't push down
aggregate to iceberg",
+ aggregate,
+ e.getMessage());
+ return false;
+ }
+ } else {
+ // only push down aggregates iff all of them can be pushed down.
+ LOG.info(
+ "Failed to convert this aggregate function to iceberg Aggregate,
can't push down aggregate to iceberg",
+ aggregate);
+ return false;
+ }
+ }
+
+ this.aggregateExpressions = expressions;
+
+ pushedAggregateSchema =
+ SparkPushedDownAggregateUtil.buildSchemaForPushedDownAggregate(
+ aggregateExpressions, caseSensitive, schema);
+ if (pushedAggregateSchema != null
Review Comment:
What if the aggregation can't be pushed down because of missing metadata?
For example, if lower/upper bounds are missing for a column because the metrics
mode doesn't track the metadata?
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