Ńņ
[Jc @ s d Z d d k i Z d d k l Z d d k l Z d d k l Z d d g Z
d e f d YZ d e f d YZ d S(
s$ Horizontal 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 file ``examples/sharding/attribute_shard.py``
included in the source distrbution.
i’’’’N( t util( t Session( t Queryt ShardedSessiont ShardedQueryc B sA e Z d d Z d d d d Z d d d d Z d Z RS( c K s t t | i | | | _ | | _ | | _ h | _ h | i d 6| _ t | _
| d j o) x& | D] } | i | | | qj Wn d S( s Construct a ShardedSession.
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.
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.
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.
t connection_callableN(
t superR t __init__t
shard_choosert
id_choosert
query_choosert _ShardedSession__bindst
connectiont _mapper_flush_optsR t
_query_clst Nonet
bind_shard( t selfR R R
t shardst kwargst k( ( s8 /usr/lib/python2.6/site-packages/sqlalchemy/orm/shard.pyR s
c K sp | d j o | i | | } n | i d j o | i i | d | S| i | d | d | i | Sd S( Nt shard_idt instance( R R t transactionR t get_bindt contextual_connect( R t mapperR R R ( ( s8 /usr/lib/python2.6/site-packages/sqlalchemy/orm/shard.pyR ; s
c K s4 | d j o | i | | d | } n | i | S( Nt clause( R R R ( R R R R R t kw( ( s8 /usr/lib/python2.6/site-packages/sqlalchemy/orm/shard.pyR D s
c C s | | i | s 3