ó H`¾Tc@srdZddlmZddlmZddlmZddgZdefd„ƒYZdefd„ƒYZ d S( sHorizontal sharding support. Defines a rudimental 'horizontal sharding' system which allows a Session to distribute queries and persistence operations across multiple databases. For a usage example, see the :ref:`examples_sharding` example included in the source distribution. i(tutil(tSession(tQuerytShardedSessiont ShardedQuerycBs,eZd„Zd„Zd„Zd„ZRS(cOsDtt|ƒj||Ž|jj|_|jj|_d|_dS(N(tsuperRt__init__tsessiont id_choosert query_choosertNonet _shard_id(tselftargstkwargs((se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyRscCs|jƒ}||_|S(s¹return a new query, limited to a single shard ID. all subsequent operations with the returned query will be against the single shard regardless of other state. (t_cloneR (R tshard_idtq((se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyt set_shard s  cso‡‡fd†}ˆjdk r.|ˆjƒSg}x*ˆjˆƒD]}|j||ƒƒqDWt|ƒSdS(NcsM|ˆjd<ˆjdˆjƒd|ƒjˆjˆjƒ}ˆj|ˆƒS(NRtmapper(t attributest_connection_from_sessiont _mapper_zerotexecutet statementt_paramst instances(Rtresult(R tcontext(se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pytiter_for_shard,s     (R R R textendtiter(R RRtpartialR((R Rse/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyt_execute_and_instances+s  cKs„|jdk r%tt|ƒj|ƒStj|ƒ}xI|j||ƒD]1}|j|ƒj||}|dk rG|SqGWdSdS(N( R R RRtgetRtto_listRR(R tidentRRto((se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyR"@s (t__name__t __module__RRR!R"(((se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyRs  cBsDeZded„Zdddd„Zdddd„Zd„ZRS(cKs„tt|ƒjd||||_||_||_i|_|j|_|dk r€x%|D]}|j |||ƒq_WndS(sConstruct a ShardedSession. :param shard_chooser: A callable which, passed a Mapper, a mapped instance, and possibly a SQL clause, returns a shard ID. This id may be based off of the attributes present within the object, or on some round-robin scheme. If the scheme is based on a selection, it should set whatever state on the instance to mark it in the future as participating in that shard. :param id_chooser: A callable, passed a query and a tuple of identity values, which should return a list of shard ids where the ID might reside. The databases will be queried in the order of this listing. :param query_chooser: For a given Query, returns the list of shard_ids where the query should be issued. Results from all shards returned will be combined together into a single listing. :param shards: A dictionary of string shard names to :class:`~sqlalchemy.engine.Engine` objects. t query_clsN( RRRt shard_chooserRR t_ShardedSession__bindst connectiontconnection_callableR t bind_shard(R R)RR tshardsR(Rtk((se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyRNs       cKsl|dkr!|j||ƒ}n|jdk rF|jj|d|ƒS|j|d|d|ƒj|SdS(NRtinstance(R R)t transactionR+tget_bindtcontextual_connect(R RR0RR((se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyR+os  cKs2|dkr'|j||d|ƒ}n|j|S(Ntclause(R R)R*(R RRR0R4tkw((se/var/www/send.findwatt.com/datamanager/lib/python2.7/site-packages/sqlalchemy/ext/horizontal_shard.pyR2|s cCs||j|s  4