add fetch_row test

src/storage/compression/dictionary/decompression.cpp

@@ -42,16 +42,16 @@ void CompressedStringScanState::Initialize(ColumnSegment &segment, bool initiali
 
 	block_size = segment.GetBlockManager().GetBlockSize();
 
+	dict = DictionaryCompression::GetDictionary(segment, *handle);
+	dictionary = make_buffer<Vector>(segment.type, index_buffer_count);
+	dictionary_size = index_buffer_count;
+
 	if (!initialize_dictionary) {
 		// Used by fetch, as fetch will never produce a DictionaryVector
 		return;
 	}
 
-	dict = DictionaryCompression::GetDictionary(segment, *handle);
-	dictionary = make_buffer<Vector>(segment.type, index_buffer_count);
-	dictionary_size = index_buffer_count;
 	auto dict_child_data = FlatVector::GetData<string_t>(*(dictionary));
-
 	for (uint32_t i = 0; i < index_buffer_count; i++) {
 		// NOTE: the passing of dict_child_vector, will not be used, its for big strings
 		uint16_t str_len = GetStringLength(i);

src/storage/compression/dictionary_compression.cpp

@@ -150,7 +150,7 @@ void DictionaryCompressionStorage::StringFetchRow(ColumnSegment &segment, Column
 	// fetch a single row from the string segment
 	CompressedStringScanState scan_state(state.GetOrInsertHandle(segment));
 	scan_state.Initialize(segment, false);
-	scan_state.ScanToFlatVector(result, result_idx, static_cast<idx_t>(row_id), 1);
+	scan_state.ScanToFlatVector(result, result_idx, NumericCast<idx_t>(row_id), 1);
 }
 
 //===--------------------------------------------------------------------===//

test/sql/storage/compression/dictionary/fetch_row.test

@@ -0,0 +1,51 @@
+# name: test/sql/storage/compression/dictionary/fetch_row.test
+# description: Test storage with Dictionary compression
+# group: [dictionary]
+
+require block_size 262144
+
+# load the DB from disk
+load __TEST_DIR__/test_dictionary_fetchrow.db
+
+statement ok
+PRAGMA force_compression = 'dictionary'
+
+statement ok
+CREATE TABLE test (
+	a INTEGER,
+	b VARCHAR
+);
+
+statement ok
+INSERT INTO test (a, b)
+SELECT x AS a, 
+       CASE (x - 1) % 5
+           WHEN 0 THEN 'aaaa'
+           WHEN 1 THEN 'bbbb'
+           WHEN 2 THEN 'cccc'
+           WHEN 3 THEN 'dddd'
+           WHEN 4 THEN NULL
+       END AS b
+FROM range(10_000) t(x);
+
+statement ok
+CHECKPOINT
+
+restart
+
+query I
+SELECT compression FROM pragma_storage_info('test') WHERE segment_type ILIKE 'VARCHAR' LIMIT 1
+----
+Dictionary
+
+statement ok
+pragma verify_fetch_row;
+
+query I
+select distinct b from test order by a % 5;
+----
+NULL
+aaaa
+bbbb
+cccc
+dddd