Add total files filtered

scripts/generate_test_data.py

@@ -180,7 +180,7 @@ def generate_test_data_pyspark(name, current_path, input_path, delete_predicate
 
 ## Partitioned table with all types we can file skip on
 for type in ["bool", "int", "tinyint", "smallint", "bigint", "float", "double", "varchar"]:
-    query = f"CREATE table test_table as select i::{type} as value, i::{type} as part from range(0,2) tbl(i)"
+    query = f"CREATE table test_table as select i::{type} as value1, (i)::{type} as value2, (i)::{type} as value3, i::{type} as part from range(0,5) tbl(i)"
     generate_test_data_delta_rs(f"test_file_skipping/{type}", query, "part")
 
 ## Simple table with deletion vector

src/delta_extension.cpp

@@ -52,6 +52,11 @@ static void LoadInternal(DatabaseInstance &instance) {
 	// Register the "single table" delta catalog (to ATTACH a single delta table)
 	auto &config = DBConfig::GetConfig(instance);
 	config.storage_extensions["delta"] = make_uniq<DeltaStorageExtension>();
+
+	config.AddExtensionOption("delta_scan_explain_files_filtered",
+	                          "Adds the filtered files to the explain output. Warning: this may change performance of "
+	                          "delta scan during explain analyze queries.",
+	                          LogicalType::BOOLEAN, Value(true));
 }
 
 void DeltaExtension::Load(DuckDB &db) {

src/functions/delta_scan.cpp

@@ -15,6 +15,7 @@
 #include "duckdb/parser/parsed_expression.hpp"
 #include "duckdb/planner/binder.hpp"
 #include "duckdb/planner/operator/logical_get.hpp"
+#include "duckdb/main/query_profiler.hpp"
 
 #include <duckdb/main/client_data.hpp>
 #include <numeric>
@@ -523,19 +524,67 @@ unique_ptr<MultiFileList> DeltaSnapshot::ComplexFilterPushdown(ClientContext &co
 		return nullptr;
 	}
 
-	for (const auto &filter : filters) {
-		combiner.AddFilter(filter->Copy());
+	for (auto riter = filters.rbegin(); riter != filters.rend(); ++riter) {
+		combiner.AddFilter(riter->get()->Copy());
 	}
+
 	auto filterstmp = combiner.GenerateTableScanFilters(info.column_indexes);
 
-	// TODO: can/should we figure out if this filtered anything?
 	auto filtered_list = make_uniq<DeltaSnapshot>(context, paths[0]);
 	filtered_list->table_filters = std::move(filterstmp);
 	filtered_list->names = names;
 
 	// Copy over the snapshot, this avoids reparsing metadata
 	filtered_list->snapshot = snapshot;
 
+	auto &profiler = QueryProfiler::Get(context);
+
+	// Note: this is potentially quite expensive: we are creating 2 scans of the snapshot and fully materializing both
+	// file lists Therefore this is only done when profile is enabled. This is enable by default in debug mode or for
+	// EXPLAIN ANALYZE queries
+	if (profiler.IsEnabled()) {
+		Value result;
+		if (!context.TryGetCurrentSetting("delta_scan_explain_files_filtered", result)) {
+			throw InternalException("Failed to find 'delta_scan_explain_files_filtered' option!");
+		} else if (result.GetValue<bool>()) {
+			auto old_total = GetTotalFileCount();
+			auto new_total = filtered_list->GetTotalFileCount();
+
+			if (old_total != new_total) {
+				string filters_info;
+				bool first_item = true;
+				for (auto &f : filtered_list->table_filters.filters) {
+					auto &column_index = f.first;
+					auto &filter = f.second;
+					if (column_index < names.size()) {
+						if (!first_item) {
+							filters_info += "\n";
+						}
+						first_item = false;
+						auto &col_name = names[column_index];
+						filters_info += filter->ToString(col_name);
+					}
+				}
+
+				info.extra_info.file_filters = filters_info;
+			}
+
+			if (!info.extra_info.total_files.IsValid()) {
+				info.extra_info.total_files = old_total;
+			} else if (info.extra_info.total_files.GetIndex() < old_total) {
+				throw InternalException(
+				    "Error encountered when analyzing filtered out files for delta scan: total_files inconsistent!");
+			}
+
+			if (!info.extra_info.filtered_files.IsValid() || info.extra_info.filtered_files.GetIndex() >= new_total) {
+				info.extra_info.filtered_files = new_total;
+			} else {
+				throw InternalException(
+				    "Error encountered when analyzing filtered out files for delta scan: filtered_files inconsistent!");
+			}
+		}
+	}
+
 	return std::move(filtered_list);
 }
 

test/sql/generated/file_skipping_all_types.test

@@ -8,37 +8,127 @@ require delta
 
 require-env GENERATED_DATA_AVAILABLE
 
-# TODO: this doesn't appear to skip files yet
-# TODO: add tests once https://github.com/duckdb/duckdb/pull/12488 is available
+foreach type float double
 
-query I
-select value
-from delta_scan('./data/generated/test_file_skipping/bool/delta_lake')
-where part != false
-order by value
+# using <type> column to skip files
+query II
+EXPLAIN ANALYZE SELECT value1, value2, value3
+FROM delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
+WHERE
+    value1 > 0.5 and
+    value2 > 2.5 and
+    value3 < 3.5
 ----
-true
+analyzed_plan	<REGEX>:.*File Filters:.*value1>0.5.*value2>2.5.*value3<3.5.*Scanning Files: 1/5.*
 
-foreach type bool int tinyint smallint bigint varchar
+query III
+SELECT value1, value2, value3
+FROM delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
+WHERE
+    value1 > 0.5 and
+    value2 > 2.5 and
+    value3 < 3.5
+----
+3.0	3.0	3.0
 
-query I
-select value
-from delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
-where part != 0
-order by value
+# FIXME: Partition columns currently don't cause file skipping yet
+query II
+EXPLAIN ANALYZE SELECT part
+FROM delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
+WHERE part > 0.5
 ----
-1
+analyzed_plan	<!REGEX>:.*File Filters:.*
 
 endloop
 
-foreach type float double
+# use bool column to skip files
+query II
+EXPLAIN ANALYZE SELECT *
+FROM delta_scan('./data/generated/test_file_skipping/bool/delta_lake')
+WHERE value1=false
+----
+analyzed_plan	<REGEX>:.*File Filters:.*value1=false.*Scanning Files: 1/2.*
+
+# FIXME: Partition columns currently don't cause file skipping yet
+query II
+EXPLAIN ANALYZE SELECT part
+FROM delta_scan('./data/generated/test_file_skipping/bool/delta_lake')
+WHERE part=false
+----
+analyzed_plan	<!REGEX>:.*File Filters:.*
+
+foreach type int tinyint smallint bigint
+
+# using <type> column to skip files
+query II
+EXPLAIN ANALYZE SELECT value1, value2, value3
+FROM delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
+WHERE
+    value1 > 1 and
+    value2 > 2 and
+    value3 < 4
+----
+analyzed_plan	<REGEX>:.*File Filters:.*value1>1.*value2>2.*value3<4.*Scanning Files: 1/5.*
+
+query III
+SELECT value1, value2, value3
+FROM delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
+WHERE
+    value1 > 1 and
+    value2 > 2 and
+    value3 < 4
+----
+3	3	3
 
-query I
-select value
-from delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
-where part > 0.5
-order by value
+# FIXME: Partition columns currently don't cause file skipping yet
+query II
+EXPLAIN ANALYZE SELECT part
+FROM delta_scan('./data/generated/test_file_skipping/${type}/delta_lake')
+WHERE part = 0
 ----
-1.0
+analyzed_plan	<!REGEX>:.*File Filters:.*
 
 endloop
+
+# using <type> column to skip files
+query II
+EXPLAIN ANALYZE SELECT value1, value2, value3
+FROM delta_scan('./data/generated/test_file_skipping/varchar/delta_lake')
+WHERE
+    value1 = '2' and
+    value2 = '2' and
+    value3 = '2'
+----
+analyzed_plan	<REGEX>:.*File Filters:.*value1='2'.*value2='2'.*value3='2'.*Scanning Files: 1/5.*
+
+query III
+SELECT value1, value2, value3
+FROM delta_scan('./data/generated/test_file_skipping/varchar/delta_lake')
+WHERE
+    value1 = '2' and
+    value2 = '2' and
+    value3 = '2'
+----
+2	2	2
+
+# FIXME: Partition columns currently don't cause file skipping yet
+query II
+EXPLAIN ANALYZE SELECT part
+FROM delta_scan('./data/generated/test_file_skipping/varchar/delta_lake')
+WHERE part = '0'
+----
+analyzed_plan	<!REGEX>:.*File Filters:.*
+
+# We can remove this from output if precise operator timing is crucial
+statement ok
+set delta_scan_explain_files_filtered = false;
+
+query II
+EXPLAIN ANALYZE SELECT value1, value2, value3
+FROM delta_scan('./data/generated/test_file_skipping/varchar/delta_lake')
+WHERE
+    value1 = '2' and
+    value2 = '2' and
+    value3 = '2'
+----
+analyzed_plan	<!REGEX>:.*File Filters:.*