Files
odoo_source/odoo/tools/cache.py
T
Xavier Morel 9d37cecfca [FIX] core: iterations on LRU
Iteration methods on LRU were removed because they were not
thread-safe and it's not clear that making them thread-safe is the
correct thing to do, so not providing them seems saner.

I thought I'd looked for usages of the LRU but apparently didn't look
hard enough as I missed that it's used by the cron workers (apparently
using the threaded server we only run crons for dbs currently living
in the registry cache, the more you know).

Convert these to iterating on the LRU's internal mapping, and also
don't iterate on the LRU to clear its entries one by one when we can
just clear the entire thing safely, although Registry.delete_all
really seems completely unused.

closes odoo/odoo#49023

Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>
2020-04-06 09:45:29 +00:00

236 lines
8.2 KiB
Python

# -*- coding: utf-8 -*-
# Part of Odoo. See LICENSE file for full copyright and licensing details.
# decorator makes wrappers that have the same API as their wrapped function
from collections import defaultdict
from decorator import decorator
from inspect import signature
import logging
unsafe_eval = eval
_logger = logging.getLogger(__name__)
class ormcache_counter(object):
""" Statistic counters for cache entries. """
__slots__ = ['hit', 'miss', 'err']
def __init__(self):
self.hit = 0
self.miss = 0
self.err = 0
@property
def ratio(self):
return 100.0 * self.hit / (self.hit + self.miss or 1)
# statistic counters dictionary, maps (dbname, modelname, method) to counter
STAT = defaultdict(ormcache_counter)
class ormcache(object):
""" LRU cache decorator for model methods.
The parameters are strings that represent expressions referring to the
signature of the decorated method, and are used to compute a cache key::
@ormcache('model_name', 'mode')
def _compute_domain(self, model_name, mode="read"):
...
For the sake of backward compatibility, the decorator supports the named
parameter `skiparg`::
@ormcache(skiparg=1)
def _compute_domain(self, model_name, mode="read"):
...
Methods implementing this decorator should never return a Recordset,
because the underlying cursor will eventually be closed and raise a
`psycopg2.OperationalError`.
"""
def __init__(self, *args, **kwargs):
self.args = args
self.skiparg = kwargs.get('skiparg')
def __call__(self, method):
self.method = method
self.determine_key()
lookup = decorator(self.lookup, method)
lookup.clear_cache = self.clear
return lookup
def determine_key(self):
""" Determine the function that computes a cache key from arguments. """
if self.skiparg is None:
# build a string that represents function code and evaluate it
args = str(signature(self.method))[1:-1]
if self.args:
code = "lambda %s: (%s,)" % (args, ", ".join(self.args))
else:
code = "lambda %s: ()" % (args,)
self.key = unsafe_eval(code)
else:
# backward-compatible function that uses self.skiparg
self.key = lambda *args, **kwargs: args[self.skiparg:]
def lru(self, model):
counter = STAT[(model.pool.db_name, model._name, self.method)]
return model.pool.cache, (model._name, self.method), counter
def lookup(self, method, *args, **kwargs):
d, key0, counter = self.lru(args[0])
key = key0 + self.key(*args, **kwargs)
try:
r = d[key]
counter.hit += 1
return r
except KeyError:
counter.miss += 1
value = d[key] = self.method(*args, **kwargs)
return value
except TypeError:
_logger.warning("cache lookup error on %r", key, exc_info=True)
counter.err += 1
return self.method(*args, **kwargs)
def clear(self, model, *args):
""" Clear the registry cache """
model.pool._clear_cache()
class ormcache_context(ormcache):
""" This LRU cache decorator is a variant of :class:`ormcache`, with an
extra parameter ``keys`` that defines a sequence of dictionary keys. Those
keys are looked up in the ``context`` parameter and combined to the cache
key made by :class:`ormcache`.
"""
def __init__(self, *args, **kwargs):
super(ormcache_context, self).__init__(*args, **kwargs)
self.keys = kwargs['keys']
def determine_key(self):
""" Determine the function that computes a cache key from arguments. """
assert self.skiparg is None, "ormcache_context() no longer supports skiparg"
# build a string that represents function code and evaluate it
sign = signature(self.method)
args = str(sign)[1:-1]
cont_expr = "(context or {})" if 'context' in sign.parameters else "self._context"
keys_expr = "tuple(%s.get(k) for k in %r)" % (cont_expr, self.keys)
if self.args:
code = "lambda %s: (%s, %s)" % (args, ", ".join(self.args), keys_expr)
else:
code = "lambda %s: (%s,)" % (args, keys_expr)
self.key = unsafe_eval(code)
class ormcache_multi(ormcache):
""" This LRU cache decorator is a variant of :class:`ormcache`, with an
extra parameter ``multi`` that gives the name of a parameter. Upon call, the
corresponding argument is iterated on, and every value leads to a cache
entry under its own key.
"""
def __init__(self, *args, **kwargs):
super(ormcache_multi, self).__init__(*args, **kwargs)
self.multi = kwargs['multi']
def determine_key(self):
""" Determine the function that computes a cache key from arguments. """
assert self.skiparg is None, "ormcache_multi() no longer supports skiparg"
assert isinstance(self.multi, str), "ormcache_multi() parameter multi must be an argument name"
super(ormcache_multi, self).determine_key()
# key_multi computes the extra element added to the key
sign = signature(self.method)
args = str(sign)[1:-1]
code_multi = "lambda %s: %s" % (args, self.multi)
self.key_multi = unsafe_eval(code_multi)
# self.multi_pos is the position of self.multi in args
self.multi_pos = list(sign.parameters).index(self.multi)
def lookup(self, method, *args, **kwargs):
d, key0, counter = self.lru(args[0])
base_key = key0 + self.key(*args, **kwargs)
ids = self.key_multi(*args, **kwargs)
result = {}
missed = []
# first take what is available in the cache
for i in ids:
key = base_key + (i,)
try:
result[i] = d[key]
counter.hit += 1
except Exception:
counter.miss += 1
missed.append(i)
if missed:
# call the method for the ids that were not in the cache; note that
# thanks to decorator(), the multi argument will be bound and passed
# positionally in args.
args = list(args)
args[self.multi_pos] = missed
result.update(method(*args, **kwargs))
# store those new results back in the cache
for i in missed:
key = base_key + (i,)
d[key] = result[i]
return result
class dummy_cache(object):
""" Cache decorator replacement to actually do no caching. """
def __init__(self, *l, **kw):
pass
def __call__(self, fn):
fn.clear_cache = self.clear
return fn
def clear(self, *l, **kw):
pass
def log_ormcache_stats(sig=None, frame=None):
""" Log statistics of ormcache usage by database, model, and method. """
from odoo.modules.registry import Registry
import threading
me = threading.currentThread()
me_dbname = getattr(me, 'dbname', 'n/a')
for dbname, reg in sorted(Registry.registries.d.items()):
# set logger prefix to dbname
me.dbname = dbname
entries = defaultdict(int)
# beware: we use .keys() on purpose here (reg.cache is not a real dict)
for key in reg.cache.keys():
entries[key[:2]] += 1
# show entries sorted by model name, method name
for key in sorted(entries, key=lambda key: (key[0], key[1].__name__)):
model, method = key
stat = STAT[(dbname, model, method)]
_logger.info(
"%6d entries, %6d hit, %6d miss, %6d err, %4.1f%% ratio, for %s.%s",
entries[key], stat.hit, stat.miss, stat.err, stat.ratio, model, method.__name__,
)
me.dbname = me_dbname
def get_cache_key_counter(bound_method, *args, **kwargs):
""" Return the cache, key and stat counter for the given call. """
model = bound_method.__self__
ormcache = bound_method.clear_cache.__self__
cache, key0, counter = ormcache.lru(model)
key = key0 + ormcache.key(model, *args, **kwargs)
return cache, key, counter
# For backward compatibility
cache = ormcache