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
46 psycopg2.extensions.register_type(psycopg2.extensions.UNICODE)
48 _logger = logging.getLogger(__name__)
56 def unbuffer(symb, cr):
57 if symb is None: return None
60 def undecimalize(symb, cr):
61 if symb is None: return None
64 for name, typeoid in types_mapping.items():
65 psycopg2.extensions.register_type(psycopg2.extensions.new_type(typeoid, name, lambda x, cr: x))
66 psycopg2.extensions.register_type(psycopg2.extensions.new_type((700, 701, 1700,), 'float', undecimalize))
70 from tools.func import frame_codeinfo
71 from datetime import datetime as mdt
72 from datetime import timedelta
74 from inspect import currentframe
77 re_from = re.compile('.* from "?([a-zA-Z_0-9]+)"? .*$');
78 re_into = re.compile('.* into "?([a-zA-Z_0-9]+)"? .*$');
83 """Represents an open transaction to the PostgreSQL DB backend,
84 acting as a lightweight wrapper around psycopg2's
85 ``psycopg1cursor`` objects.
87 ``Cursor`` is the object behind the ``cr`` variable used all
88 over the OpenERP code.
90 .. rubric:: Transaction Isolation
92 One very important property of database transactions is the
93 level of isolation between concurrent transactions.
94 The SQL standard defines four levels of transaction isolation,
95 ranging from the most strict *Serializable* level, to the least
96 strict *Read Uncommitted* level. These levels are defined in
97 terms of the phenomena that must not occur between concurrent
98 transactions, such as *dirty read*, etc.
99 In the context of a generic business data management software
100 such as OpenERP, we need the best guarantees that no data
101 corruption can ever be cause by simply running multiple
102 transactions in parallel. Therefore, the preferred level would
103 be the *serializable* level, which ensures that a set of
104 transactions is guaranteed to produce the same effect as
105 running them one at a time in some order.
107 However, most database management systems implement a limited
108 serializable isolation in the form of
109 `snapshot isolation <http://en.wikipedia.org/wiki/Snapshot_isolation>`_,
110 providing most of the same advantages as True Serializability,
111 with a fraction of the performance cost.
112 With PostgreSQL up to version 9.0, this snapshot isolation was
113 the implementation of both the ``REPEATABLE READ`` and
114 ``SERIALIZABLE`` levels of the SQL standard.
115 As of PostgreSQL 9.1, the previous snapshot isolation implementation
116 was kept for ``REPEATABLE READ``, while a new ``SERIALIZABLE``
117 level was introduced, providing some additional heuristics to
118 detect a concurrent update by parallel transactions, and forcing
119 one of them to rollback.
121 OpenERP implements its own level of locking protection
122 for transactions that are highly likely to provoke concurrent
123 updates, such as stock reservations or document sequences updates.
124 Therefore we mostly care about the properties of snapshot isolation,
125 but we don't really need additional heuristics to trigger transaction
126 rollbacks, as we are taking care of triggering instant rollbacks
127 ourselves when it matters (and we can save the additional performance
128 hit of these heuristics).
130 As a result of the above, we have selected ``REPEATABLE READ`` as
131 the default transaction isolation level for OpenERP cursors, as
132 it will be mapped to the desired ``snapshot isolation`` level for
133 all supported PostgreSQL version (8.3 - 9.x).
135 Note: up to psycopg2 v.2.4.2, psycopg2 itself remapped the repeatable
136 read level to serializable before sending it to the database, so it would
137 actually select the new serializable mode on PostgreSQL 9.1. Make
138 sure you use psycopg2 v2.4.2 or newer if you use PostgreSQL 9.1 and
139 the performance hit is a concern for you.
142 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 self.sql_from_log = {}
157 self.sql_into_log = {}
159 # default log level determined at cursor creation, could be
160 # overridden later for debugging purposes
161 self.sql_log = _logger.isEnabledFor(logging.DEBUG)
163 self.sql_log_count = 0
164 self.__closed = True # avoid the call of close() (by __del__) if an exception
165 # is raised by any of the following initialisations
169 # Whether to enable snapshot isolation level for this cursor.
170 # see also the docstring of Cursor.
171 self._serialized = serialized
173 self._cnx = pool.borrow(dsn(dbname))
174 self._obj = self._cnx.cursor(cursor_factory=psycopg1cursor)
176 self.__caller = frame_codeinfo(currentframe(),2)
178 self.__caller = False
179 self.__closed = False # real initialisation value
180 self.autocommit(False)
181 self.__closer = False
183 self._default_log_exceptions = True
186 if not self.__closed and not self._cnx.closed:
187 # Oops. 'self' has not been closed explicitly.
188 # The cursor will be deleted by the garbage collector,
189 # but the database connection is not put back into the connection
190 # pool, preventing some operation on the database like dropping it.
191 # This can also lead to a server overload.
192 msg = "Cursor not closed explicitly\n"
194 msg += "Cursor was created at %s:%s" % self.__caller
196 msg += "Please enable sql debugging to trace the caller."
201 def execute(self, query, params=None, log_exceptions=None):
202 if '%d' in query or '%f' in query:
203 _logger.warning(query)
204 _logger.warning("SQL queries cannot contain %d or %f anymore. "
211 params = params or None
212 res = self._obj.execute(query, params)
213 except psycopg2.ProgrammingError, pe:
214 if (self._default_log_exceptions if log_exceptions is None else log_exceptions):
215 _logger.error("Programming error: %s, in query %s", pe, query)
218 if (self._default_log_exceptions if log_exceptions is None else log_exceptions):
219 _logger.exception("bad query: %s", self._obj.query or query)
223 delay = mdt.now() - now
224 delay = delay.seconds * 1E6 + delay.microseconds
226 _logger.debug("query: %s", self._obj.query)
227 self.sql_log_count+=1
228 res_from = re_from.match(query.lower())
230 self.sql_from_log.setdefault(res_from.group(1), [0, 0])
231 self.sql_from_log[res_from.group(1)][0] += 1
232 self.sql_from_log[res_from.group(1)][1] += delay
233 res_into = re_into.match(query.lower())
235 self.sql_into_log.setdefault(res_into.group(1), [0, 0])
236 self.sql_into_log[res_into.group(1)][0] += 1
237 self.sql_into_log[res_into.group(1)][1] += delay
241 def split_for_in_conditions(self, ids):
242 """Split a list of identifiers into one or more smaller tuples
243 safe for IN conditions, after uniquifying them."""
244 return tools.misc.split_every(self.IN_MAX, set(ids))
248 sql_counter += self.sql_log_count
252 sqllogs = {'from':self.sql_from_log, 'into':self.sql_into_log}
255 sqllogitems = sqllogs[type].items()
256 sqllogitems.sort(key=lambda k: k[1][1])
257 _logger.debug("SQL LOG %s:", type)
258 sqllogitems.sort(lambda x,y: cmp(x[1][0], y[1][0]))
259 for r in sqllogitems:
260 delay = timedelta(microseconds=r[1][1])
261 _logger.debug("table: %s: %s/%s",
262 r[0], delay, r[1][0])
264 sqllogs[type].clear()
265 sum = timedelta(microseconds=sum)
266 _logger.debug("SUM %s:%s/%d [%d]",
267 type, sum, self.sql_log_count, sql_counter)
268 sqllogs[type].clear()
271 self.sql_log_count = 0
276 return self._close(False)
278 def _close(self, leak=False):
283 self.__closer = frame_codeinfo(currentframe(),3)
288 # This force the cursor to be freed, and thus, available again. It is
289 # important because otherwise we can overload the server very easily
290 # because of a cursor shortage (because cursors are not garbage
291 # collected as fast as they should). The problem is probably due in
292 # part because browse records keep a reference to the cursor.
296 # Clean the underlying connection.
300 self._cnx.leaked = True
302 chosen_template = tools.config['db_template']
303 templates_list = tuple(set(['template0', 'template1', 'postgres', chosen_template]))
304 keep_in_pool = self.dbname not in templates_list
305 self._pool.give_back(self._cnx, keep_in_pool=keep_in_pool)
308 def autocommit(self, on):
310 isolation_level = ISOLATION_LEVEL_AUTOCOMMIT
312 # If a serializable cursor was requested, we
313 # use the appropriate PotsgreSQL isolation level
314 # that maps to snaphsot isolation.
315 # For all supported PostgreSQL versions (8.3-9.x),
316 # this is currently the ISOLATION_REPEATABLE_READ.
317 # See also the docstring of this class.
318 # NOTE: up to psycopg 2.4.2, repeatable read
319 # is remapped to serializable before being
320 # sent to the database, so it is in fact
321 # unavailable for use with pg 9.1.
322 isolation_level = ISOLATION_LEVEL_REPEATABLE_READ \
323 if self._serialized \
324 else ISOLATION_LEVEL_READ_COMMITTED
325 self._cnx.set_isolation_level(isolation_level)
329 """ Perform an SQL `COMMIT`
331 return self._cnx.commit()
335 """ Perform an SQL `ROLLBACK`
337 return self._cnx.rollback()
340 def __getattr__(self, name):
341 return getattr(self._obj, name)
343 """ Set the mode of postgres operations for all cursors
345 """Obtain the mode of postgres operations for all cursors
348 class PsycoConnection(psycopg2.extensions.connection):
351 class ConnectionPool(object):
352 """ The pool of connections to database(s)
354 Keep a set of connections to pg databases open, and reuse them
355 to open cursors for all transactions.
357 The connections are *not* automatically closed. Only a close_db()
363 def _locked(self, *args, **kwargs):
366 return fun(self, *args, **kwargs)
372 def __init__(self, maxconn=64):
373 self._connections = []
374 self._maxconn = max(maxconn, 1)
375 self._lock = threading.Lock()
378 used = len([1 for c, u in self._connections[:] if u])
379 count = len(self._connections)
380 return "ConnectionPool(used=%d/count=%d/max=%d)" % (used, count, self._maxconn)
382 def _debug(self, msg, *args):
383 _logger.debug(('%r ' + msg), self, *args)
386 def borrow(self, dsn):
387 self._debug('Borrow connection to %r', dsn)
389 # free leaked connections
390 for i, (cnx, _) in tools.reverse_enumerate(self._connections):
392 self._connections.pop(i)
393 self._debug('Removing closed connection at index %d: %r', i, cnx.dsn)
395 if getattr(cnx, 'leaked', False):
396 delattr(cnx, 'leaked')
397 self._connections.pop(i)
398 self._connections.append((cnx, False))
399 _logger.warning('%r: Free leaked connection to %r', self, cnx.dsn)
401 for i, (cnx, used) in enumerate(self._connections):
402 if not used and dsn_are_equals(cnx.dsn, dsn):
403 self._connections.pop(i)
404 self._connections.append((cnx, True))
405 self._debug('Existing connection found at index %d', i)
409 if len(self._connections) >= self._maxconn:
410 # try to remove the oldest connection not used
411 for i, (cnx, used) in enumerate(self._connections):
413 self._connections.pop(i)
414 self._debug('Removing old connection at index %d: %r', i, cnx.dsn)
417 # note: this code is called only if the for loop has completed (no break)
418 raise PoolError('The Connection Pool Is Full')
421 result = psycopg2.connect(dsn=dsn, connection_factory=PsycoConnection)
422 except psycopg2.Error:
423 _logger.exception('Connection to the database failed')
425 self._connections.append((result, True))
426 self._debug('Create new connection')
430 def give_back(self, connection, keep_in_pool=True):
431 self._debug('Give back connection to %r', connection.dsn)
432 for i, (cnx, used) in enumerate(self._connections):
433 if cnx is connection:
434 self._connections.pop(i)
436 self._connections.append((cnx, False))
437 self._debug('Put connection to %r in pool', cnx.dsn)
439 self._debug('Forgot connection to %r', cnx.dsn)
443 raise PoolError('This connection does not below to the pool')
446 def close_all(self, dsn):
447 _logger.info('%r: Close all connections to %r', self, dsn)
448 for i, (cnx, used) in tools.reverse_enumerate(self._connections):
449 if dsn_are_equals(cnx.dsn, dsn):
451 self._connections.pop(i)
454 class Connection(object):
455 """ A lightweight instance of a connection to postgres
458 def __init__(self, pool, dbname):
462 def cursor(self, serialized=True):
463 cursor_type = serialized and 'serialized ' or ''
464 _logger.debug('create %scursor to %r', cursor_type, self.dbname)
465 return Cursor(self._pool, self.dbname, serialized=serialized)
467 # serialized_cursor is deprecated - cursors are serialized by default
468 serialized_cursor = cursor
470 def __nonzero__(self):
471 """Check if connection is possible"""
473 _logger.warning("__nonzero__() is deprecated. (It is too expensive to test a connection.)")
482 for p in ('host', 'port', 'user', 'password'):
483 cfg = tools.config['db_' + p]
485 _dsn += '%s=%s ' % (p, cfg)
487 return '%sdbname=%s' % (_dsn, db_name)
489 def dsn_are_equals(first, second):
491 k = dict(x.split('=', 1) for x in dsn.strip().split())
492 k.pop('password', None) # password is not relevant
494 return key(first) == key(second)
499 def db_connect(db_name):
502 _Pool = ConnectionPool(int(tools.config['db_maxconn']))
503 currentThread().dbname = db_name
504 return Connection(_Pool, db_name)
506 def close_db(db_name):
508 """ You might want to call openerp.modules.registry.RegistryManager.delete(db_name) along this function."""
510 _Pool.close_all(dsn(db_name))
512 if hasattr(ct, 'dbname'):
513 delattr(ct, 'dbname')
516 # vim:expandtab:smartindent:tabstop=4:softtabstop=4:shiftwidth=4: