diff options
| -rw-r--r-- | Doc/library/functools.rst | 6 | ||||
| -rw-r--r-- | Doc/whatsnew/3.2.rst | 8 | ||||
| -rw-r--r-- | Lib/functools.py | 13 |
3 files changed, 12 insertions, 15 deletions
diff --git a/Doc/library/functools.rst b/Doc/library/functools.rst index a8fc856..5b65874 100644 --- a/Doc/library/functools.rst +++ b/Doc/library/functools.rst @@ -72,10 +72,10 @@ The :mod:`functools` module defines the following functions: A `LRU (least recently used) cache <http://en.wikipedia.org/wiki/Cache_algorithms#Least_Recently_Used>`_ - is indicated when the pattern of calls changes over time, such as - when more recent calls are the best predictors of upcoming calls + works best when more recent calls are the best predictors of upcoming calls (for example, the most popular articles on a news server tend to - change every day). + change each day). The cache's size limit assurs that caching does not + grow without bound on long-running processes such as web servers. .. versionadded:: 3.2 diff --git a/Doc/whatsnew/3.2.rst b/Doc/whatsnew/3.2.rst index 91ab849..2d1f0ef 100644 --- a/Doc/whatsnew/3.2.rst +++ b/Doc/whatsnew/3.2.rst @@ -332,15 +332,13 @@ New, Improved, and Deprecated Modules c.execute('SELECT phonenumber FROM phonelist WHERE name=?', (name,)) return c.fetchone()[0] - XXX: update for Issue 10586 changes to cache statistics API - To help with choosing an effective cache size, the wrapped function is - instrumented with two attributes *cache_hits* and *cache_misses*: + instrumented with info function: >>> for name in user_requests: ... get_phone_number(name) - >>> print(get_phone_number.cache_hits, get_phone_number.cache_misses) - 4805 980 + >>> get_phone_number.cache_info() + CacheInfo(maxsize=300, size=300, hits=4805, misses=980) If the phonelist table gets updated, the outdated contents of the cache can be cleared with: diff --git a/Lib/functools.py b/Lib/functools.py index c223a62..e8e9960 100644 --- a/Lib/functools.py +++ b/Lib/functools.py @@ -121,16 +121,15 @@ def lru_cache(maxsize=100): Arguments to the cached function must be hashable. - Significant statistics (maxsize, size, hits, misses) are - available through the f.cache_info() named tuple. - Clear the cache and statistics using f.cache_clear(). - The underlying function is stored in f.__wrapped__. + View the cache statistics named tuple (maxsize, size, hits, misses) with + f.cache_info(). Clear the cache and statistics with f.cache_clear(). + And access the underlying function with f.__wrapped__. See: http://en.wikipedia.org/wiki/Cache_algorithms#Least_Recently_Used """ # Users should only access the lru_cache through its public API: - # cache_info, cache_clear, and f.__wrapped__ + # cache_info, cache_clear, and f.__wrapped__ # The internals of the lru_cache are encapsulated for thread safety and # to allow the implementation to change (including a possible C version). @@ -141,7 +140,7 @@ def lru_cache(maxsize=100): cache_popitem = cache.popitem cache_renew = cache.move_to_end hits = misses = 0 - kwd_mark = object() # separate positional and keyword args + kwd_mark = object() # separates positional and keyword args lock = Lock() @wraps(user_function) @@ -165,7 +164,7 @@ def lru_cache(maxsize=100): return result def cache_info(): - """Report significant cache statistics""" + """Report cache statistics""" with lock: return _CacheInfo(maxsize, len(cache), hits, misses) |