1 # -*- coding: utf-8 -*-
2 ##############################################################################
4 # OpenERP, Open Source Management Solution
5 # Copyright (C) 2004-2009 Tiny SPRL (<http://tiny.be>).
6 # Copyright (C) 2010-2011 OpenERP s.a. (<http://openerp.com>).
8 # This program is free software: you can redistribute it and/or modify
9 # it under the terms of the GNU Affero General Public License as
10 # published by the Free Software Foundation, either version 3 of the
11 # License, or (at your option) any later version.
13 # This program is distributed in the hope that it will be useful,
14 # but WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU Affero General Public License for more details.
18 # You should have received a copy of the GNU Affero General Public License
19 # along with this program. If not, see <http://www.gnu.org/licenses/>.
21 ##############################################################################
23 #.apidoc title: PostgreSQL interface
26 The PostgreSQL connector is a connectivity layer between the OpenERP code and
27 the database, *not* a database abstraction toolkit. Database abstraction is what
28 the ORM does, in fact.
30 See also: the `pooler` module
33 #.apidoc add-functions: print_stats
34 #.apidoc add-classes: Cursor Connection ConnectionPool
36 __all__ = ['db_connect', 'close_db']
38 from functools import wraps
40 import psycopg2.extensions
41 from psycopg2.extensions import ISOLATION_LEVEL_AUTOCOMMIT, ISOLATION_LEVEL_READ_COMMITTED, ISOLATION_LEVEL_REPEATABLE_READ
42 from psycopg2.pool import PoolError
43 from psycopg2.psycopg1 import cursor as psycopg1cursor
44 from threading import currentThread
47 psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
55 def unbuffer(symb, cr):
56 if symb is None: return None
59 def undecimalize(symb, cr):
60 if symb is None: return None
63 for name, typeoid in types_mapping.items():
64 psycopg2.extensions.register_type(psycopg2.extensions.new_type(typeoid, name, lambda x, cr: x))
65 psycopg2.extensions.register_type(psycopg2.extensions.new_type((700, 701, 1700,), 'float', undecimalize))
69 from tools.func import frame_codeinfo
70 from datetime import datetime as mdt
71 from datetime import timedelta
73 from inspect import currentframe
76 re_from = re.compile('.* from "?([a-zA-Z_0-9]+)"? .*$');
77 re_into = re.compile('.* into "?([a-zA-Z_0-9]+)"? .*$');
82 """Represents an open transaction to the PostgreSQL DB backend,
83 acting as a lightweight wrapper around psycopg2's
84 ``psycopg1cursor`` objects.
86 ``Cursor`` is the object behind the ``cr`` variable used all
87 over the OpenERP code.
89 .. rubric:: Transaction Isolation
91 One very important property of database transactions is the
92 level of isolation between concurrent transactions.
93 The SQL standard defines four levels of transaction isolation,
94 ranging from the most strict *Serializable* level, to the least
95 strict *Read Uncommitted* level. These levels are defined in
96 terms of the phenomena that must not occur between concurrent
97 transactions, such as *dirty read*, etc.
98 In the context of a generic business data management software
99 such as OpenERP, we need the best guarantees that no data
100 corruption can ever be cause by simply running multiple
101 transactions in parallel. Therefore, the preferred level would
102 be the *serializable* level, which ensures that a set of
103 transactions is guaranteed to produce the same effect as
104 running them one at a time in some order.
106 However, most database management systems implement a limited
107 serializable isolation in the form of
108 `snapshot isolation <http://en.wikipedia.org/wiki/Snapshot_isolation>`_,
109 providing most of the same advantages as True Serializability,
110 with a fraction of the performance cost.
111 With PostgreSQL up to version 9.0, this snapshot isolation was
112 the implementation of both the ``REPEATABLE READ`` and
113 ``SERIALIZABLE`` levels of the SQL standard.
114 As of PostgreSQL 9.1, the previous snapshot isolation implementation
115 was kept for ``REPEATABLE READ``, while a new ``SERIALIZABLE``
116 level was introduced, providing some additional heuristics to
117 detect a concurrent update by parallel transactions, and forcing
118 one of them to rollback.
120 OpenERP implements its own level of locking protection
121 for transactions that are highly likely to provoke concurrent
122 updates, such as stock reservations or document sequences updates.
123 Therefore we mostly care about the properties of snapshot isolation,
124 but we don't really need additional heuristics to trigger transaction
125 rollbacks, as we are taking care of triggering instant rollbacks
126 ourselves when it matters (and we can save the additional performance
127 hit of these heuristics).
129 As a result of the above, we have selected ``REPEATABLE READ`` as
130 the default transaction isolation level for OpenERP cursors, as
131 it will be mapped to the desired ``snapshot isolation`` level for
132 all supported PostgreSQL version (8.3 - 9.x).
134 Note: up to psycopg2 v.2.4.2, psycopg2 itself remapped the repeatable
135 read level to serializable before sending it to the database, so it would
136 actually select the new serializable mode on PostgreSQL 9.1. Make
137 sure you use psycopg2 v2.4.2 or newer if you use PostgreSQL 9.1 and
138 the performance hit is a concern for you.
141 IN_MAX = 1000 # decent limit on size of IN queries - guideline = Oracle limit
146 def wrapper(self, *args, **kwargs):
148 msg = 'Unable to use a closed cursor.'
150 msg += ' It was closed at %s, line %s' % self.__closer
151 raise psycopg2.OperationalError(msg)
152 return f(self, *args, **kwargs)
155 def __init__(self, pool, dbname, serialized=True):
156 if self.__class__.__logger is None:
157 self.__class__.__logger = logging.getLogger('db.cursor')
158 self.sql_from_log = {}
159 self.sql_into_log = {}
161 # default log level determined at cursor creation, could be
162 # overridden later for debugging purposes
163 self.sql_log = self.__logger.isEnabledFor(logging.DEBUG_SQL)
165 self.sql_log_count = 0
166 self.__closed = True # avoid the call of close() (by __del__) if an exception
167 # is raised by any of the following initialisations
171 # Whether to enable snapshot isolation level for this cursor.
172 # see also the docstring of Cursor.
173 self._serialized = serialized
175 self._cnx = pool.borrow(dsn(dbname))
176 self._obj = self._cnx.cursor(cursor_factory=psycopg1cursor)
178 self.__caller = frame_codeinfo(currentframe(),2)
180 self.__caller = False
181 self.__closed = False # real initialisation value
182 self.autocommit(False)
183 self.__closer = False
185 self._default_log_exceptions = True
188 if not self.__closed and not self._cnx.closed:
189 # Oops. 'self' has not been closed explicitly.
190 # The cursor will be deleted by the garbage collector,
191 # but the database connection is not put back into the connection
192 # pool, preventing some operation on the database like dropping it.
193 # This can also lead to a server overload.
194 msg = "Cursor not closed explicitly\n"
196 msg += "Cursor was created at %s:%s" % self.__caller
198 msg += "Please enable sql debugging to trace the caller."
199 self.__logger.warn(msg)
203 def execute(self, query, params=None, log_exceptions=None):
204 if '%d' in query or '%f' in query:
205 self.__logger.warn(query)
206 self.__logger.warn("SQL queries cannot contain %d or %f anymore. "
213 params = params or None
214 res = self._obj.execute(query, params)
215 except psycopg2.ProgrammingError, pe:
216 if (self._default_log_exceptions if log_exceptions is None else log_exceptions):
217 self.__logger.error("Programming error: %s, in query %s", pe, query)
220 if (self._default_log_exceptions if log_exceptions is None else log_exceptions):
221 self.__logger.exception("bad query: %s", self._obj.query or query)
225 delay = mdt.now() - now
226 delay = delay.seconds * 1E6 + delay.microseconds
228 self.__logger.log(logging.DEBUG_SQL, "query: %s", self._obj.query)
229 self.sql_log_count+=1
230 res_from = re_from.match(query.lower())
232 self.sql_from_log.setdefault(res_from.group(1), [0, 0])
233 self.sql_from_log[res_from.group(1)][0] += 1
234 self.sql_from_log[res_from.group(1)][1] += delay
235 res_into = re_into.match(query.lower())
237 self.sql_into_log.setdefault(res_into.group(1), [0, 0])
238 self.sql_into_log[res_into.group(1)][0] += 1
239 self.sql_into_log[res_into.group(1)][1] += delay
243 def split_for_in_conditions(self, ids):
244 """Split a list of identifiers into one or more smaller tuples
245 safe for IN conditions, after uniquifying them."""
246 return tools.misc.split_every(self.IN_MAX, set(ids))
250 sql_counter += self.sql_log_count
254 sqllogs = {'from':self.sql_from_log, 'into':self.sql_into_log}
257 sqllogitems = sqllogs[type].items()
258 sqllogitems.sort(key=lambda k: k[1][1])
259 self.__logger.log(logging.DEBUG_SQL, "SQL LOG %s:", type)
260 sqllogitems.sort(lambda x,y: cmp(x[1][0], y[1][0]))
261 for r in sqllogitems:
262 delay = timedelta(microseconds=r[1][1])
263 self.__logger.log(logging.DEBUG_SQL, "table: %s: %s/%s",
264 r[0], delay, r[1][0])
266 sqllogs[type].clear()
267 sum = timedelta(microseconds=sum)
268 self.__logger.log(logging.DEBUG_SQL, "SUM %s:%s/%d [%d]",
269 type, sum, self.sql_log_count, sql_counter)
270 sqllogs[type].clear()
273 self.sql_log_count = 0
278 return self._close(False)
280 def _close(self, leak=False):
285 self.__closer = frame_codeinfo(currentframe(),3)
290 # This force the cursor to be freed, and thus, available again. It is
291 # important because otherwise we can overload the server very easily
292 # because of a cursor shortage (because cursors are not garbage
293 # collected as fast as they should). The problem is probably due in
294 # part because browse records keep a reference to the cursor.
298 # Clean the underlying connection.
302 self._cnx.leaked = True
304 chosen_template = tools.config['db_template']
305 templates_list = tuple(set(['template0', 'template1', 'postgres', chosen_template]))
306 keep_in_pool = self.dbname not in templates_list
307 self._pool.give_back(self._cnx, keep_in_pool=keep_in_pool)
310 def autocommit(self, on):
312 isolation_level = ISOLATION_LEVEL_AUTOCOMMIT
314 # If a serializable cursor was requested, we
315 # use the appropriate PotsgreSQL isolation level
316 # that maps to snaphsot isolation.
317 # For all supported PostgreSQL versions (8.3-9.x),
318 # this is currently the ISOLATION_REPEATABLE_READ.
319 # See also the docstring of this class.
320 # NOTE: up to psycopg 2.4.2, repeatable read
321 # is remapped to serializable before being
322 # sent to the database, so it is in fact
323 # unavailable for use with pg 9.1.
324 isolation_level = ISOLATION_LEVEL_REPEATABLE_READ \
325 if self._serialized \
326 else ISOLATION_LEVEL_READ_COMMITTED
327 self._cnx.set_isolation_level(isolation_level)
331 """ Perform an SQL `COMMIT`
333 return self._cnx.commit()
337 """ Perform an SQL `ROLLBACK`
339 return self._cnx.rollback()
342 def __getattr__(self, name):
343 return getattr(self._obj, name)
345 """ Set the mode of postgres operations for all cursors
347 """Obtain the mode of postgres operations for all cursors
350 class PsycoConnection(psycopg2.extensions.connection):
353 class ConnectionPool(object):
354 """ The pool of connections to database(s)
356 Keep a set of connections to pg databases open, and reuse them
357 to open cursors for all transactions.
359 The connections are *not* automatically closed. Only a close_db()
362 __logger = logging.getLogger('db.connection_pool')
366 def _locked(self, *args, **kwargs):
369 return fun(self, *args, **kwargs)
375 def __init__(self, maxconn=64):
376 self._connections = []
377 self._maxconn = max(maxconn, 1)
378 self._lock = threading.Lock()
381 used = len([1 for c, u in self._connections[:] if u])
382 count = len(self._connections)
383 return "ConnectionPool(used=%d/count=%d/max=%d)" % (used, count, self._maxconn)
385 def _debug(self, msg, *args):
386 self.__logger.log(logging.DEBUG_SQL, ('%r ' + msg), self, *args)
389 def borrow(self, dsn):
390 self._debug('Borrow connection to %r', dsn)
392 # free leaked connections
393 for i, (cnx, _) in tools.reverse_enumerate(self._connections):
395 self._connections.pop(i)
396 self._debug('Removing closed connection at index %d: %r', i, cnx.dsn)
398 if getattr(cnx, 'leaked', False):
399 delattr(cnx, 'leaked')
400 self._connections.pop(i)
401 self._connections.append((cnx, False))
402 self.__logger.warn('%r: Free leaked connection to %r', self, cnx.dsn)
404 for i, (cnx, used) in enumerate(self._connections):
405 if not used and dsn_are_equals(cnx.dsn, dsn):
406 self._connections.pop(i)
407 self._connections.append((cnx, True))
408 self._debug('Existing connection found at index %d', i)
412 if len(self._connections) >= self._maxconn:
413 # try to remove the oldest connection not used
414 for i, (cnx, used) in enumerate(self._connections):
416 self._connections.pop(i)
417 self._debug('Removing old connection at index %d: %r', i, cnx.dsn)
420 # note: this code is called only if the for loop has completed (no break)
421 raise PoolError('The Connection Pool Is Full')
424 result = psycopg2.connect(dsn=dsn, connection_factory=PsycoConnection)
425 except psycopg2.Error:
426 self.__logger.exception('Connection to the database failed')
428 self._connections.append((result, True))
429 self._debug('Create new connection')
433 def give_back(self, connection, keep_in_pool=True):
434 self._debug('Give back connection to %r', connection.dsn)
435 for i, (cnx, used) in enumerate(self._connections):
436 if cnx is connection:
437 self._connections.pop(i)
439 self._connections.append((cnx, False))
440 self._debug('Put connection to %r in pool', cnx.dsn)
442 self._debug('Forgot connection to %r', cnx.dsn)
446 raise PoolError('This connection does not below to the pool')
449 def close_all(self, dsn):
450 self.__logger.info('%r: Close all connections to %r', self, dsn)
451 for i, (cnx, used) in tools.reverse_enumerate(self._connections):
452 if dsn_are_equals(cnx.dsn, dsn):
454 self._connections.pop(i)
457 class Connection(object):
458 """ A lightweight instance of a connection to postgres
460 __logger = logging.getLogger('db.connection')
462 def __init__(self, pool, dbname):
466 def cursor(self, serialized=True):
467 cursor_type = serialized and 'serialized ' or ''
468 self.__logger.log(logging.DEBUG_SQL, 'create %scursor to %r', cursor_type, self.dbname)
469 return Cursor(self._pool, self.dbname, serialized=serialized)
471 # serialized_cursor is deprecated - cursors are serialized by default
472 serialized_cursor = cursor
474 def __nonzero__(self):
475 """Check if connection is possible"""
477 warnings.warn("You use an expensive function to test a connection.",
478 DeprecationWarning, stacklevel=1)
487 for p in ('host', 'port', 'user', 'password'):
488 cfg = tools.config['db_' + p]
490 _dsn += '%s=%s ' % (p, cfg)
492 return '%sdbname=%s' % (_dsn, db_name)
494 def dsn_are_equals(first, second):
496 k = dict(x.split('=', 1) for x in dsn.strip().split())
497 k.pop('password', None) # password is not relevant
499 return key(first) == key(second)
504 def db_connect(db_name):
507 _Pool = ConnectionPool(int(tools.config['db_maxconn']))
508 currentThread().dbname = db_name
509 return Connection(_Pool, db_name)
511 def close_db(db_name):
512 """ You might want to call openerp.modules.registry.RegistryManager.delete(db_name) along this function."""
513 _Pool.close_all(dsn(db_name))
515 if hasattr(ct, 'dbname'):
516 delattr(ct, 'dbname')
519 # vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4: