Added/Updated tests\bugs\core_6458_test.py: refactored: replaced old stupid delay with loop which does query to mon$ tables per small interval.

tests/bugs/core_6458_test.py

@@ -6,7 +6,9 @@ ISSUE:       6691
 TITLE:       Regression: Cancel Query function no longer works
 DESCRIPTION:
   We create .sql script with 'heavy query' that for sure will run more than several seconds.
-  Then we launch asynchronous ISQL process to perform this query and take small pause for 1-2 second.
+  Then we launch asynchronously ISQL to perform this query and wait until its PID and running
+  query will appear in the mon$ tables (we are looking for query that containing text 'HEAVY_TAG').
+
   After this we send signal CTRL_C_EVENT for emulating interruption that is done by pressing Ctrl-C.
   Then we wait for process finish (call wait() method) - this is necessary if ISQL will continue
   without interruprion (i.e. if something will be broken again).
@@ -29,18 +31,25 @@ DESCRIPTION:
 
   Confirmed bug on 4.0.0.2307: query could NOT be interrupted and we had to wait until it completed.
   Checked on 4.0.0.2324 (SS/CS): works OK, query can be interrupted via sending Ctrl-C signal.
+
 JIRA:        CORE-6458
 FBTEST:      bugs.core_6458
 """
 
-import pytest
 import re
 import signal
 import subprocess
+from datetime import datetime as dt
 import time
 from pathlib import Path
+from firebird.driver import DatabaseError, tpb, Isolation, TraLockResolution, DatabaseError
+
+import pytest
 from firebird.qa import *
 
+MAX_WAIT_FOR_ISQL_PID_APPEARS_MS = 10000
+HEAVY_TAG = '/* HEAVY_TAG */'
+
 db = db_factory()
 
 act = python_act('db')
@@ -58,17 +67,66 @@ heavy_stderr = temp_file('heavy_script.err')
 @pytest.mark.version('>=4.0')
 def test_1(act: Action, heavy_script: Path, heavy_stdout: Path, heavy_stderr: Path,
            capsys):
-    heavy_script.write_text("set list on; select count(*) as LONG_QUERY_RESULT from (select 1 i from rdb$types a,rdb$types b,rdb$types c);")
+    heavy_script.write_text(f"set list on; select {HEAVY_TAG} count(*) as LONG_QUERY_RESULT from (select 1 i from rdb$types a,rdb$types b,rdb$types c,rdb$types d,rdb$types e);")
     with open(heavy_stdout, mode='w') as heavy_out, open(heavy_stderr, mode='w') as heavy_err:
         # NB: subprocess.CREATE_NEW_PROCESS_GROUP is MANDATORY FOR SENDING CTRL_C SIGNAL on Windows
         flags = 0 if act.platform == 'Linux' else subprocess.CREATE_NEW_PROCESS_GROUP
-        p_heavy_sql = subprocess.Popen([act.vars['isql'], '-i', str(heavy_script),
-                                        '-user', act.db.user,
-                                       '-password', act.db.password, act.db.dsn],
-                                       stdout=heavy_out, stderr=heavy_err,
-                                       creationflags=flags)
+        p_heavy_sql = subprocess.Popen( [ act.vars['isql'],
+                                          '-i', str(heavy_script),
+                                          '-user', act.db.user,
+                                          '-password', act.db.password,
+                                          act.db.dsn
+                                        ],
+                                        stdout=heavy_out,
+                                        stderr=heavy_err,
+                                        creationflags=flags
+                                      )
+        
+        chk_mon_sql = """
+            select 1
+            from mon$attachments a
+            join mon$statements s
+            using (mon$attachment_id)
+            where
+                a.mon$attachment_id <> current_connection
+                and a.mon$remote_pid = ?
+                and s.mon$sql_text containing ?
+        """
+
+        found_in_mon_tables = False
+        with act.db.connect() as con_watcher:
+
+            custom_tpb = tpb(isolation = Isolation.SNAPSHOT, lock_timeout = -1)
+            tx_watcher = con_watcher.transaction_manager(custom_tpb)
+            cur_watcher = tx_watcher.cursor()
+
+            ps = cur_watcher.prepare(chk_mon_sql)
+
+            i = 0
+            da = dt.now()
+            while True:
+                cur_watcher.execute(ps, (p_heavy_sql.pid, HEAVY_TAG,) )
+                mon_result = -1
+                for r in cur_watcher:
+                    mon_result = r[0]
+
+                tx_watcher.commit()
+                db = dt.now()
+                diff_ms = (db-da).seconds*1000 + (db-da).microseconds//1000
+                if mon_result == 1:
+                    found_in_mon_tables = True
+                    break
+                elif diff_ms > MAX_WAIT_FOR_ISQL_PID_APPEARS_MS:
+                    break
+
+                time.sleep(0.1)
+
+            ps.free()
+
+        assert found_in_mon_tables, f'Could not find attachment in mon$ tables for {MAX_WAIT_FOR_ISQL_PID_APPEARS_MS} ms.'
+        
+        
         try:
-            time.sleep(4)
             p_heavy_sql.send_signal(signal.SIGINT if act.platform == 'Linux' else signal.CTRL_C_EVENT)
             p_heavy_sql.wait()
             print('Was ISQL process terminated ? => ', p_heavy_sql.poll())