xudong963 commented on code in PR #20003:
URL: https://github.com/apache/datafusion/pull/20003#discussion_r2730956061
##########
datafusion/optimizer/src/push_down_filter.rs:
##########
@@ -1154,34 +1160,109 @@ impl OptimizerRule for PushDownFilter {
.map(|(pred, _)| pred);
// Add new scan filters
- let new_scan_filters: Vec<Expr> = scan
- .filters
- .iter()
- .chain(new_scan_filters)
- .unique()
- .cloned()
- .collect();
+ let new_scan_filters: Vec<Expr> =
+ new_scan_filters.unique().cloned().collect();
+
+ let source_schema = scan.source.schema();
+ let mut additional_projection = HashSet::new();
// Compose predicates to be of `Unsupported` or `Inexact`
pushdown type, and also include volatile filters
let new_predicate: Vec<Expr> = zip
- .filter(|(_, res)| res !=
&TableProviderFilterPushDown::Exact)
+ .filter(|(expr, res)| {
+ if *res == TableProviderFilterPushDown::Exact {
+ return false;
+ }
+ // For each not exactly supported filter we must
ensure that all columns are projected,
+ // so we collect all columns which are not currently
projected.
+ expr.apply(|expr| {
+ if let Expr::Column(column) = expr
+ && let Ok(idx) =
source_schema.index_of(column.name())
+ && scan
+ .projection
+ .as_ref()
+ .is_some_and(|p| !p.contains(&idx))
+ {
+ additional_projection.insert(idx);
+ }
+ Ok(TreeNodeRecursion::Continue)
+ })
+ .unwrap();
+ true
+ })
.map(|(pred, _)| pred)
.chain(volatile_filters)
.cloned()
.collect();
- let new_scan = LogicalPlan::TableScan(TableScan {
- filters: new_scan_filters,
- ..scan
- });
-
- Transformed::yes(new_scan).transform_data(|new_scan| {
- if let Some(predicate) = conjunction(new_predicate) {
- make_filter(predicate,
Arc::new(new_scan)).map(Transformed::yes)
+ // Wraps with a filter if some filters are not supported
exactly.
+ let filtered = move |plan| {
+ if let Some(new_predicate) = conjunction(new_predicate) {
+ Filter::try_new(new_predicate, Arc::new(plan))
+ .map(LogicalPlan::Filter)
} else {
- Ok(Transformed::no(new_scan))
+ Ok(plan)
}
- })
+ };
+
+ if additional_projection.is_empty() {
+ // No additional projection is required.
+ let new_scan = LogicalPlan::TableScan(TableScan {
+ filters: new_scan_filters,
+ ..scan
+ });
+ return filtered(new_scan).map(Transformed::yes);
+ }
+
+ let scan_table_name = &scan.table_name;
+ let new_scan = filtered(
+ LogicalPlanBuilder::scan_with_filters_fetch(
+ scan_table_name.clone(),
+ Arc::clone(&scan.source),
+ scan.projection.clone().map(|mut projection| {
+ // Extend a projection.
+ projection.extend(additional_projection);
Review Comment:
There should be a tradeoff between fetching an extra column from storage vs
the selectivity of the related filter
##########
datafusion/optimizer/src/push_down_filter.rs:
##########
@@ -1154,34 +1160,109 @@ impl OptimizerRule for PushDownFilter {
.map(|(pred, _)| pred);
// Add new scan filters
- let new_scan_filters: Vec<Expr> = scan
- .filters
- .iter()
- .chain(new_scan_filters)
- .unique()
- .cloned()
- .collect();
+ let new_scan_filters: Vec<Expr> =
+ new_scan_filters.unique().cloned().collect();
+
+ let source_schema = scan.source.schema();
+ let mut additional_projection = HashSet::new();
// Compose predicates to be of `Unsupported` or `Inexact`
pushdown type, and also include volatile filters
let new_predicate: Vec<Expr> = zip
- .filter(|(_, res)| res !=
&TableProviderFilterPushDown::Exact)
+ .filter(|(expr, res)| {
+ if *res == TableProviderFilterPushDown::Exact {
+ return false;
+ }
+ // For each not exactly supported filter we must
ensure that all columns are projected,
+ // so we collect all columns which are not currently
projected.
+ expr.apply(|expr| {
+ if let Expr::Column(column) = expr
+ && let Ok(idx) =
source_schema.index_of(column.name())
+ && scan
+ .projection
+ .as_ref()
+ .is_some_and(|p| !p.contains(&idx))
+ {
+ additional_projection.insert(idx);
+ }
+ Ok(TreeNodeRecursion::Continue)
+ })
+ .unwrap();
+ true
+ })
.map(|(pred, _)| pred)
.chain(volatile_filters)
.cloned()
.collect();
- let new_scan = LogicalPlan::TableScan(TableScan {
- filters: new_scan_filters,
- ..scan
- });
-
- Transformed::yes(new_scan).transform_data(|new_scan| {
- if let Some(predicate) = conjunction(new_predicate) {
- make_filter(predicate,
Arc::new(new_scan)).map(Transformed::yes)
+ // Wraps with a filter if some filters are not supported
exactly.
+ let filtered = move |plan| {
+ if let Some(new_predicate) = conjunction(new_predicate) {
+ Filter::try_new(new_predicate, Arc::new(plan))
+ .map(LogicalPlan::Filter)
} else {
- Ok(Transformed::no(new_scan))
+ Ok(plan)
}
- })
+ };
+
+ if additional_projection.is_empty() {
Review Comment:
The branch of scan is expanding, any thoughts to split the branch
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