How to set cache size in ZODB?

Question

I establish ZODB connection with the following code:

connection = ZODB.connection('zodb/connect4_reinf.fs')
dbroot = connection.root()

How can I set RAM cache size?

Answer 1

From the source code of class DB:

  def __init__(self, storage,
             pool_size=7,
             pool_timeout=1<<31,
             cache_size=400,
             cache_size_bytes=0,
             historical_pool_size=3,
             historical_cache_size=1000,
             historical_cache_size_bytes=0,
             historical_timeout=300,
             database_name='unnamed',
             databases=None,
             xrefs=True,
             large_record_size=1<<24,
             **storage_args):

When ZODB.connection is defined as follows:

def connection(*args, **kw):
    return DB(*args, **kw).open_then_close_db_when_connection_closes()

I would say

   connection = ZODB.connection('zodb/connect4_reinf.fs',
        cache_size=<your-cache-size>)

Also there's a cache_size_bytes if you prefer the limit to be in (estimated) bytes. 0 means unlimited for this parameter.