Merge pull request #35311 from vdimir/pmj-dup-rows

Attempt to fix merge join duplicate rows

src/Interpreters/MergeJoin.cpp

@@ -881,6 +881,7 @@ bool MergeJoin::leftJoin(MergeJoinCursor & left_cursor, const Block & left_block
             {
                 right_cursor.nextN(range.right_length);
                 right_block_info.skip = right_cursor.position();
+                left_cursor.nextN(range.left_length);
                 return false;
             }
         }

tests/queries/0_stateless/02177_issue_31009_pt2.reference

@@ -0,0 +1,28 @@
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tests/queries/0_stateless/02177_issue_31009_pt2.sql.j2

@@ -0,0 +1,37 @@
+-- Tags: long
+
+DROP TABLE IF EXISTS left;
+DROP TABLE IF EXISTS right;
+
+SET join_algorithm = 'partial_merge';
+
+{% for block_size in [10, 11, 128, 129, 65505, 65506, 70000] -%}
+{% for join_block_size in range(block_size - 2, block_size + 2) -%}
+
+CREATE OR REPLACE TABLE left ( key UInt32, value String ) ENGINE = Memory;
+CREATE OR REPLACE TABLE right (  key UInt32, value String ) ENGINE = Memory;
+
+INSERT INTO left SELECT number, toString(number) FROM numbers({{ block_size * 2 + 1 }});
+INSERT INTO right SELECT number, toString(number) FROM numbers({{ block_size * 2 + 5 }});
+
+SET max_joined_block_size_rows = {{ join_block_size }};
+SET max_block_size = {{ block_size }};
+
+SELECT key, count(1) AS cnt
+FROM (
+    SELECT *
+    FROM ( SELECT key FROM left AS s ) AS data
+    ALL LEFT JOIN ( SELECT key FROM right GROUP BY key ) AS promo ON promo.key = data.key
+) GROUP BY key HAVING count(1) > 1
+;
+
+SELECT count() == (SELECT count() from left) AND min(key == promo.key) == 1
+FROM ( SELECT key FROM left AS s ) AS data
+ALL LEFT JOIN ( SELECT key FROM right GROUP BY key ) AS promo ON promo.key = data.key
+;
+
+{% endfor -%}
+{% endfor -%}
+
+DROP TABLE IF EXISTS left;
+DROP TABLE IF EXISTS right;