extremely speedup of all database operations:

ChangeLog

@@ -30,6 +30,11 @@ ver. 0.9.5 (2016/XX/XXX) - wanna-be-released
    * New Actions:
      - action.d/firewallcmd-rich-rules and action.d/firewallcmd-rich-logging (gh-1367)
 - Enhancements:
+   * Extreme speedup of all sqlite database operations (gh-1436),
+     by using of following sqlite options:
+     - (synchronous = OFF) write data through OS without syncing
+     - (journal_mode = MEMORY) use memory for the transaction logging
+     - (temp_store = MEMORY) temporary tables and indices are kept in memory
    * journald journalmatch for pure-ftpd (gh-1362)
    * Add additional regex filter for dovecot ldap authentication failures (gh-1370)
    * added additional regex filters for exim (gh-1371)

fail2ban/server/database.py

@@ -181,8 +181,23 @@ def __init__(self, filename, purgeAge=24*60*60):
 				filename, e.args[0])
 			raise
 
+		# differentiate pypy: switch journal mode later (save it during the upgrade), 
+		# to prevent errors like "database table is locked":
+		try:
+			import __pypy__
+			pypy = True
+		except ImportError:
+			pypy = False
+
 		cur = self._db.cursor()
-		cur.execute("PRAGMA foreign_keys = ON;")
+		cur.execute("PRAGMA foreign_keys = ON")
+		# speedup: write data through OS without syncing (no wait):
+		cur.execute("PRAGMA synchronous = OFF")
+		# speedup: transaction log in memory, alternate using OFF (disable, rollback will be impossible):
+		if not pypy:
+			cur.execute("PRAGMA journal_mode = MEMORY")
+		# speedup: temporary tables and indices are kept in memory:
+		cur.execute("PRAGMA temp_store = MEMORY")
 
 		try:
 			cur.execute("SELECT version FROM fail2banDb LIMIT 1")
@@ -202,6 +217,9 @@ def __init__(self, filename, purgeAge=24*60*60):
 						Fail2BanDb.__version__, version, newversion)
 					raise RuntimeError('Failed to fully update')
 		finally:
+			# pypy: set journal mode after possible upgrade db:
+			if pypy:
+				cur.execute("PRAGMA journal_mode = MEMORY")
 			cur.close()
 
 	@property
@@ -244,13 +262,14 @@ def updateDb(self, cur, version):
 
 		A timestamped backup is also created prior to attempting the update.
 		"""
-		self._dbBackupFilename = self.filename + '.' + time.strftime('%Y%m%d-%H%M%S', MyTime.gmtime())
-		shutil.copyfile(self.filename, self._dbBackupFilename)
-		logSys.info("Database backup created: %s", self._dbBackupFilename)
 		if version > Fail2BanDb.__version__:
 			raise NotImplementedError(
 						"Attempt to travel to future version of database ...how did you get here??")
 
+		self._dbBackupFilename = self.filename + '.' + time.strftime('%Y%m%d-%H%M%S', MyTime.gmtime())
+		shutil.copyfile(self.filename, self._dbBackupFilename)
+		logSys.info("Database backup created: %s", self._dbBackupFilename)
+
 		if version < 2:
 			cur.executescript("BEGIN TRANSACTION;"
 						"CREATE TEMPORARY TABLE logs_temp AS SELECT * FROM logs;"