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Diffstat (limited to 'lib/sqlalchemy/engine/create.py')
| -rw-r--r-- | lib/sqlalchemy/engine/create.py | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/lib/sqlalchemy/engine/create.py b/lib/sqlalchemy/engine/create.py index 4c912349e..9bf72eb06 100644 --- a/lib/sqlalchemy/engine/create.py +++ b/lib/sqlalchemy/engine/create.py @@ -436,7 +436,13 @@ def create_engine(url, **kwargs): .. versionadded:: 1.2.3 :param query_cache_size: size of the cache used to cache the SQL string - form of queries. Defaults to zero, which disables caching. + form of queries. Set to zero to disable caching. + + The cache is pruned of its least recently used items when its size reaches + N * 1.5. Defaults to 500, meaning the cache will always store at least + 500 SQL statements when filled, and will grow up to 750 items at which + point it is pruned back down to 500 by removing the 250 least recently + used items. Caching is accomplished on a per-statement basis by generating a cache key that represents the statement's structure, then generating @@ -446,6 +452,11 @@ def create_engine(url, **kwargs): bypass the cache. SQL logging will indicate statistics for each statement whether or not it were pull from the cache. + .. note:: some ORM functions related to unit-of-work persistence as well + as some attribute loading strategies will make use of individual + per-mapper caches outside of the main cache. + + .. seealso:: ``engine_caching`` - TODO: this will be an upcoming section describing |