Added/Updated tests\bugs\gh_6609_test.py: Confirmed bug on 3.0.7.33348. Checked on 3.0.7.33350, 4.0.5.3099, 5.0.1.1399, 6.0.0.351.

tests/bugs/gh_6609_test.py

@@ -0,0 +1,84 @@
+#coding:utf-8
+
+"""
+ID:          issue-6609
+ISSUE:       https://github.com/FirebirdSQL/firebird/issues/6609
+TITLE:       Memory leak at server, when client select computed field, which used COALESCE or CAST [CORE6370]
+DESCRIPTION:
+    Problem can be seen if we run query to mon$memory_usage before and after loop with statement described in the ticket.
+    It is important that on every iteration of loop cursor will be re-created and closed after statement execution (see 'cur2').
+    Ratio between values of mon$memory_usage was about 1.63 (for CS) and 1.26 (for SS) before fix.
+    After fix these values reduced to ~1.00 (for 3.x and 4.x), but for 5.x+ CS it is about 1.10.
+    NOTE: for Classic we have to compare mon$memory_usage that corresponds to ATTACHMENT level (see 'MON_QUERY' variable).
+NOTES:
+    [18.05.2024] pzotov
+    Confirmed bug on 3.0.7.33348 (17-JUL-2020), mon$memo_used ratio for CS: 1.63; SS: 1.26
+    Checked on:
+        3.0.7.33350, mon$memo_used ratio for CS: 1.01; SS: 1.00
+        4.0.5.3099,  mon$memo_used ratio for CS: 1.01; SS: 1.00
+        5.0.1.1399,  mon$memo_used ratio for CS: 1.11; SS: 1.02
+        6.0.0.351,   mon$memo_used ratio for CS: 1.11; SS: 1.02
+"""
+
+import pytest
+import platform
+from firebird.qa import *
+
+N_CNT = 30000
+
+init_ddl = """
+    recreate table tab1 (
+        a1 varchar(99),
+        a2 varchar(199),
+        a3 computed by (coalesce(a1, '')||'-'||coalesce(a2, ''))
+    );
+"""
+
+db = db_factory(init = init_ddl)
+act = python_act('db')
+
+@pytest.mark.version('>=3.0.0')
+def test_1(act: Action, capsys):
+
+    #if act.platform == 'Windows':
+    #    pytest.skip('Could not reproduce bug on Windows')
+
+    if act.get_server_architecture() == 'SuperServer':
+        MON_QUERY = 'select mon$memory_used from mon$memory_usage where mon$stat_group = 0'
+        MAX_THRESHOLD = 1.10
+    else:
+        MON_QUERY = """
+            select m.mon$memory_used
+            from mon$attachments a
+            join mon$memory_usage m on a.mon$stat_id = m.mon$stat_id
+            where a.mon$attachment_id = current_connection and m.mon$stat_group  = 1;
+        """
+        MAX_THRESHOLD = 1.20
+
+    mon_memo_beg = 1
+    mon_memo_end = 9999999
+    with act.db.connect() as con:
+        cur = con.cursor()
+        cur.execute(MON_QUERY)
+        mon_memo_beg = int(cur.fetchone()[0])
+        con.commit()
+
+        for i in range(N_CNT):
+            cur2 = con.cursor()
+            cur2.execute(f"select /* iter {i+1} */ t.a3 from tab1 t")
+            for r in cur2:
+                pass
+            cur2.close()
+
+        con.commit()
+        cur.execute(MON_QUERY)
+        mon_memo_end = int(cur.fetchone()[0])
+
+    msg_ok = 'Memory usage: EXPECTED'
+    if mon_memo_end / mon_memo_beg <= MAX_THRESHOLD:
+        print(msg_ok)
+    else:
+        print(f'Memory usage UNEXPECTED: {mon_memo_end} / {mon_memo_beg} = {mon_memo_end / mon_memo_beg:.2f} - greater than {MAX_THRESHOLD=}')
+    act.expected_stdout = msg_ok
+    act.stdout = capsys.readouterr().out
+    assert act.clean_stdout == act.clean_expected_stdout