Le mercredi 09 janvier 2013 19:16:02, Claudiu Saftoiu a écrit : > zodb_uri = > zeo://%(here)s/zeo.sock?cache_size=1000MB&connection_cache_size=100000&conn > ection_pool_size=30 [...] > - What is cache-size?
This is probably the "connection_cache_size" parameter. It is size in number of objects (because it's highly non-trivial to compute the size of an object), and counts the number of live objects connection tries to not exceed. A live object is a python object comming from ZODB that you can use in your code (as "a" in "a.b"). The actual number of live object can exceed this limit if there are uncommitted changes to them (so evicting them would loose those changes), or if there are strong references to them and they cannot be garbage-collected (as in, building a python list of objects: no entry can be freed until the list is). As a connection also represents a snapshot of the database, each connection has its own copy of this cache. This can matter a lot if you want many parallel transactions. connection_pool_size is related to that last point: when a transaction ends, it returns its connection to a pool, so that it can be recycled rather than created from scratch on next transaction and loosing the whole attached cache. Here again, pool size is just a hint and not a hard limit. If you go above the limit, you'll get warning logs, and if it increases further you'll get error- level logs. Set it to a value which corresponds to the number of transactions you wish to have running concurrently (in Zope, that would be the number of worker threads), so you know if something somewhere opens extra connections (bypassing transaction isolation somewhat). > - What is cache-size-bytes? This must be "cache_size" parameter. It sizes the pickle cache, ie a cache containing serialised representation of objects. Size of a pickled objet is trivial to compute, as it's just a byte string. It is here to avoid a network round-trip to ask zeo process for the object data. This cache is shared by all concurrent transactions. > - Are there any other caching options? The option to make pickle cache persistent comes to mind. There may be others, I don't recall right now. > - Where would they go in my `zeo.conf`, or if they can't go there, what > should I change so I can configure this? I tried putting them under <zeo>, > <filestorage>, and <blobstorage>, but I get "not a known key name" errors. Those parameters belong to the client part of ZODB, not the server (zeo) part. Zeo has an option nevertheless, the invalidation queue size. This is used when a client reconnects to zeo and needs to know if there are cached entries it needs to flush (ie, objects which were modified by other clients). Client remembers the latest invalidation it received, and if it's stillin the invalidation queue then client can replay further invalidation requests and evicts just modified objects. Otherwise, it needs to flush the whole cache. I don't think there are other options on zeo side. I encourage you to read the code to be sure (no need to read all of it, but there are helpful docs, comments & docstrigns all over ZODB code). Check http://www.zodb.org too. -- Vincent Pelletier _______________________________________________ For more information about ZODB, see http://zodb.org/ ZODB-Dev mailing list - ZODB-Dev@zope.org https://mail.zope.org/mailman/listinfo/zodb-dev
