[Enhancement] Optimize accessing non-existent JSON field (backport #62003) (#62133)

Co-authored-by: Murphy <96611012+murphyatwork@users.noreply.github.com>

be/src/storage/rowset/column_reader.h

@@ -199,6 +199,9 @@ public:
 
     bool has_remain_json() const { return _has_remain; }
 
+    // Return the pointer to the remain filter if it exists, otherwise return nullptr.
+    const BloomFilter* get_remain_filter() const { return _remain_filter ? _remain_filter.get() : nullptr; }
+
 private:
     StatusOr<std::unique_ptr<ColumnIterator>> _new_json_iterator(ColumnAccessPath* path = nullptr,
                                                                  const TabletColumn* column = nullptr);

be/src/storage/rowset/segment.cpp

@@ -44,6 +44,7 @@
 #include "column/schema.h"
 #include "common/logging.h"
 #include "fs/key_cache.h"
+#include "gutil/strings/split.h"
 #include "gutil/strings/substitute.h"
 #include "segment_iterator.h"
 #include "segment_options.h"
@@ -524,7 +525,25 @@ StatusOr<ColumnIteratorUPtr> Segment::_new_extended_column_iterator(const Tablet
         }
     }
 
-    // Build a regular ColumnIterator to read it
+    // case 3: check if this segment contains the specific field
+    auto& column_reader = _column_readers[source_id];
+    bool may_contains = column_reader->has_remain_json();
+    if (may_contains && column_reader->get_remain_filter() != nullptr) {
+        std::vector<std::string> paths = strings::Split(full_path, ".");
+        std::string_view leaf = paths.back();
+        may_contains = column_reader->get_remain_filter()->test_bytes(leaf.data(), leaf.size());
+    }
+    if (!may_contains) {
+        // create an iterator always return NULL for fields that don't exist in this segment
+        auto default_null_iter = std::make_unique<DefaultValueColumnIterator>(false, "", true, get_type_info(column),
+                                                                              column.length(), num_rows());
+        ColumnIteratorOptions iter_opts;
+        RETURN_IF_ERROR(default_null_iter->init(iter_opts));
+        VLOG(2) << "json field " << full_path << " not found in segment, return NULL directly";
+        return default_null_iter;
+    }
+
+    // Build a regular JsonExtractIterator to read it
     auto& source_reader = _column_readers[source_id];
     ASSIGN_OR_RETURN(auto source_iter, source_reader->new_iterator(path, &column));
     return create_json_extract_iterator(std::move(source_iter), source_reader->is_nullable(), std::string(field_name),

be/src/util/json_flattener.cpp

@@ -45,6 +45,7 @@
 #include "exprs/column_ref.h"
 #include "exprs/expr_context.h"
 #include "gutil/casts.h"
+#include "gutil/strings/split.h"
 #include "runtime/types.h"
 #include "storage/rowset/column_reader.h"
 #include "types/logical_type.h"

be/test/storage/rowset/flat_json_column_rw_test.cpp

@@ -2491,7 +2491,7 @@ TEST_F(FlatJsonColumnRWTest, testSegmentWriterIteratorWithMixedDataTypes) {
             ASSIGN_OR_ABORT(auto column_iter, segment->new_column_iterator_or_default(col, path.get()));
             ASSERT_OK(column_iter->init(column_opts));
             ASSERT_OK(column_iter->seek_to_first());
-            size_t count = 4096;
+            size_t count = 3;
             auto column = ColumnHelper::create_column(TypeDescriptor(field_type), true);
             ASSERT_OK(column_iter->next_batch(&count, column.get()));
             ASSERT_EQ(column->size(), json_strings.size());

test/sql/test_semi/R/test_flat_json_predicate

@@ -167,8 +167,6 @@ select get_json_int(j1, '$.f1') from js2 where get_json_int(j1, '$.f1') = 1;
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 1
-- AccessPathHits: 1
 - PushdownAccessPaths: 0
 -- !result
 select get_json_int(j1, '$.f2') from js2 where get_json_int(j1, '$.f1') = 1;
@@ -177,8 +175,6 @@ None
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 2
-- AccessPathHits: 2
 - PushdownAccessPaths: 0
 -- !result
 select get_json_int(j1, '$.f1') from js2 where get_json_int(j1, '$.f2') = 1;
@@ -187,8 +183,6 @@ None
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 2
-- AccessPathHits: 2
 - PushdownAccessPaths: 0
 -- !result
 select get_json_int(j1, '$.f2'), j1 from js2 where get_json_int(j1, '$.f1') = 1;
@@ -197,8 +191,7 @@ None	{"f1": 1}
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 2
-- AccessPathHits: 4
+- AccessPathHits: 2
 - PushdownAccessPaths: 2
 -- !result
 select get_json_int(j1, '$.f2'), j1 from js2 where get_json_int(j1, '$.f3') = 1;
@@ -206,8 +199,7 @@ select get_json_int(j1, '$.f2'), j1 from js2 where get_json_int(j1, '$.f3') = 1;
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 3
-- AccessPathHits: 5
+- AccessPathHits: 2
 - PushdownAccessPaths: 2
 -- !result
 select get_json_int(j1, '$.f2'), get_json_int(j1, '$.f2') from js2 where get_json_int(j1, '$.f1') = 1;
@@ -216,8 +208,6 @@ None	None
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 2
-- AccessPathHits: 2
 - PushdownAccessPaths: 0
 -- !result
 select count(get_json_int(j1, '$.f2')) from js2 ;
@@ -226,8 +216,6 @@ select count(get_json_int(j1, '$.f2')) from js2 ;
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 1
-- AccessPathHits: 1
 - PushdownAccessPaths: 0
 -- !result
 select count(get_json_int(j1, '$.f3')) from js2 ;
@@ -236,8 +224,6 @@ select count(get_json_int(j1, '$.f3')) from js2 ;
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 2
-- AccessPathHits: 2
 - PushdownAccessPaths: 0
 -- !result
 select * from js2 where get_json_int(j1, '$.f1') = -1;
@@ -507,8 +493,6 @@ select count(*) from js3 where get_json_double(j1, 'f_bool') = 1.0;
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 1
-- AccessPathHits: 1
 - PushdownAccessPaths: 0
 -- !result
 select count(*) from js3 where get_json_int(j1, 'f_int') < 500;
@@ -529,8 +513,6 @@ select count(*) from js3 where get_json_double(j1, 'f_int') < 500;
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 1
-- AccessPathHits: 1
 - PushdownAccessPaths: 0
 -- !result
 select count(*) from js3 where get_json_double(j1, 'f_double') < 500.0;
@@ -551,8 +533,6 @@ select count(*) from js3 where get_json_string(j1, 'f_double') < '500';
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 1
-- AccessPathHits: 1
 - PushdownAccessPaths: 0
 -- !result
 select count(*) from js3 where get_json_int(j1, 'f_none') IS NULL;
@@ -581,7 +561,5 @@ select count(*) from js3 where get_json_double(j1, 'f_none') < 500;
 -- !result
 select * from profile_access_path;
 -- result:
-- AccessPathExtract: 2
-- AccessPathHits: 2
 - PushdownAccessPaths: 0
 -- !result