1 files changed, 112 insertions, 0 deletions
diff --git a/misc/multithreading_crash.py b/misc/multithreading_crash.py
new file mode 100644
index 0000000..35516f9
--- /dev/null
+++ b/misc/multithreading_crash.py
@@ -0,0 +1,112 @@
+#!/usr/bin/env python
+# This is a test case I got from a user that will crash PySQLite 0.5.0.
+# It stress-tests PySQLite in multithreaded mode.
+
+import os
+import sys
+import threading
+import time
+import random
+import sqlite
+
+dbname = "test.db"
+
+#MECHANISM = "no timeout"
+#MECHANISM = "use timeout"
+#MECHANISM = "use slow busy handler"
+MECHANISM = "use fast busy handler"
+
+class Modifier(threading.Thread):
+    def __init__(self, dbname):
+        threading.Thread.__init__(self)
+        self.dbname = dbname
+    def run(self):
+        print "Modifier: start"
+        cx = sqlite.connect(self.dbname)
+        cu = cx.cursor()
+        print "Modifier: INSERTing"
+        cu.execute("INSERT INTO meta (name, value) VALUES (%s, %s)",
+                   "foo", "blah blah blah")
+        for i in range(5):
+            print "Modifier: sleeping %d" % i
+            time.sleep(1)
+        print "Modifier: committing"
+        cx.commit()
+        print "Modifier: committed"
+        cu.close()
+        cx.close()
+        print "Modifier: end"
+
+class Reader(threading.Thread):
+    def __init__(self, name, dbname):
+        threading.Thread.__init__(self, name=name)
+        self.dbname = dbname
+    def busyHandler(self, delay, table, numAttempts):
+        print "Reader %s: busyHandler(delay=%r, table=%r, numAttempts=%r)"\
+              % (self.getName(), delay, table, numAttempts)
+        time.sleep(delay)
+        return 1
+    def run(self):
+        print "Reader %s: start" % self.getName()
+        if MECHANISM == "no timeout":
+            cx = sqlite.connect(self.dbname)
+        elif MECHANISM == "use timeout":
+            cx = sqlite.connect(self.dbname, timeout=5000)
+        elif MECHANISM == "use slow busy handler":
+            cx = sqlite.connect(self.dbname)
+            cx.db.sqlite_busy_handler(self.busyHandler, 1.0)
+        elif MECHANISM == "use fast busy handler":
+            cx = sqlite.connect(self.dbname, Xtimeout=5000.0)
+            cx.db.sqlite_busy_handler(self.busyHandler, 0.1)
+        else:
+            raise ValueError("MECHANISM is not one of the expected values")
+        sleepFor = random.randint(0, 3)
+        print "Reader %s: sleeping for %d seconds" % (self.getName(), sleepFor)
+        time.sleep(sleepFor)
+        print "Reader %s: waking up" % self.getName()
+        cu = cx.cursor()
+        print "Reader %s: SELECTing" % self.getName()
+        cu.execute("SELECT name, value FROM meta WHERE name='%s'" % self.getName())
+        print "Reader %s: SELECTed %s" % (self.getName(), cu.fetchone())
+        cu.close()
+        cx.close()
+        print "Reader %s: end" % self.getName()
+
+def test_sqlite_busy():
+    """Test handling of SQL_BUSY "errors" as discussed here:
+        http://www.hwaci.com/sw/sqlite/faq.html#q7
+        http://www.sqlite.org/cvstrac/wiki?p=MultiThreading
+    
+    Algorithm:
+        - start one thread that will open the database and start modifying it
+          then sleep for a while so other threads can get in there
+        - have other thread(s) do selects from the database and see if they
+          error out, if they block, if they timeout (play with timeout
+          .connect() argument)
+    """
+    # Create a fresh starting database.
+    if os.path.exists(dbname):
+        os.remove(dbname)
+    journal = dbname+"-journal"
+    if os.path.exists(journal):
+        os.remove(journal)
+    cx = sqlite.connect(dbname)
+    cu = cx.cursor()
+    cu.execute("CREATE TABLE meta (name STRING, value STRING)")
+    cx.commit()
+    cu.close()
+    cx.close()
+    
+    modifier = Modifier(dbname)
+    readerNames = ("foo",) #XXX "bar", "baz")
+    readers = [Reader(name, dbname) for name in readerNames]
+    modifier.start()
+    for reader in readers:
+        reader.start()
+    modifier.join()
+    for reader in readers:
+        reader.join()
+
+
+if __name__ == "__main__":
+    test_sqlite_busy()