Added/Updated tests\functional\tabloid\test_95442bdf.py: Checked on intermediate snapshot 6.0.0.363 #95442bd.

tests/functional/tabloid/test_95442bdf.py

@@ -0,0 +1,83 @@
+#coding:utf-8
+
+"""
+ID:          issue-95442bdf
+ISSUE:       https://github.com/FirebirdSQL/firebird/commit/95442bdfff76d22aafb57b58894047be2a89c6ea
+TITLE:       Attempt to avoid hash joining for possible cardinality under-estimations
+DESCRIPTION:
+    Test verifies explained plan for three forms of inner join:
+        * 'normal' (or 'traditional'): 'from A join B on <expr>'
+        * 'using':   'from A join B using (<field>)
+        * 'natural': 'from A natural join B'
+    All forms must generate same plan with nested loops (i.e. without hash join).
+    Lines in each explained plan are LETF-PADDED with dot character in order to keep indentation while
+    analyzing differences between expected and actual output.
+NOTES:
+    [29.05.2024] pzotov
+    Checked on intermediate snapshot 6.0.0.363 #95442bd.
+    Thanks to dimitr for provided example.
+"""
+
+import pytest
+from firebird.qa import *
+
+init_sql = f"""
+    create table t1(id int);
+    create table t2(id int primary key using index t2_pk);
+    insert into t1(id) select row_number()over() from rdb$types,rdb$types;
+    commit;
+"""
+
+db = db_factory(init = init_sql)
+act = python_act('db')
+
+#---------------------------------------------------------
+
+def replace_leading(source, char="."):
+    stripped = source.lstrip()
+    return char * (len(source) - len(stripped)) + stripped
+
+#---------------------------------------------------------
+
+@pytest.mark.version('>=6.0')
+def test_1(act: Action, capsys):
+
+    join_expr_lst = (
+         't1 a join t2 b on a.id = b.id'
+        ,'t1 u join t2 v using(id)'
+        ,'t1 x natural join t2 y'
+    )
+
+    with act.db.connect() as con:
+        cur = con.cursor()
+        for x in join_expr_lst:
+            with cur.prepare(f'select * from ' + x) as ps:
+                print( '\n'.join([replace_leading(s) for s in ps.detailed_plan .split('\n')]) )
+   
+    act.expected_stdout = """
+        Select Expression
+        ....-> Nested Loop Join (inner)
+        ........-> Table "T1" as "A" Full Scan
+        ........-> Filter
+        ............-> Table "T2" as "B" Access By ID
+        ................-> Bitmap
+        ....................-> Index "T2_PK" Unique Scan
+
+        Select Expression
+        ....-> Nested Loop Join (inner)
+        ........-> Table "T1" as "U" Full Scan
+        ........-> Filter
+        ............-> Table "T2" as "V" Access By ID
+        ................-> Bitmap
+        ....................-> Index "T2_PK" Unique Scan
+
+        Select Expression
+        ....-> Nested Loop Join (inner)
+        ........-> Table "T1" as "X" Full Scan
+        ........-> Filter
+        ............-> Table "T2" as "Y" Access By ID
+        ................-> Bitmap
+        ....................-> Index "T2_PK" Unique Scan
+    """
+    act.stdout = capsys.readouterr().out
+    assert act.clean_stdout == act.clean_expected_stdout