diff options
Diffstat (limited to 'lib/sqlalchemy/dialects/postgresql/psycopg2.py')
| -rw-r--r-- | lib/sqlalchemy/dialects/postgresql/psycopg2.py | 46 |
1 files changed, 45 insertions, 1 deletions
diff --git a/lib/sqlalchemy/dialects/postgresql/psycopg2.py b/lib/sqlalchemy/dialects/postgresql/psycopg2.py index 3e2968d91..8ac39c201 100644 --- a/lib/sqlalchemy/dialects/postgresql/psycopg2.py +++ b/lib/sqlalchemy/dialects/postgresql/psycopg2.py @@ -53,6 +53,15 @@ psycopg2-specific keyword arguments which are accepted by :ref:`psycopg2_unicode` +* ``use_batch_mode``: This flag allows ``psycopg2.extras.execute_batch`` + for ``cursor.executemany()`` calls performed by the :class:`.Engine`. + It is currently experimental but + may well become True by default as it is critical for executemany performance. + + .. seealso:: + + :ref:`psycopg2_batch_mode` + Unix Domain Connections ------------------------ @@ -101,6 +110,31 @@ The following DBAPI-specific options are respected when used with .. versionadded:: 1.0.6 +.. _psycopg2_batch_mode: + +Psycopg2 Batch Mode (Fast Execution) +------------------------------------ + +Modern versions of psycopg2 include a feature known as +`Fast Execution Helpers <http://initd.org/psycopg/docs/extras.html#fast-execution-helpers>`_, +which have been shown in benchmarking to improve psycopg2's executemany() +performance with INSERTS by multiple orders of magnitude. SQLAlchemy +allows this extension to be used for all ``executemany()`` style calls +invoked by an :class:`.Engine` when used with multiple parameter sets, +by adding the ``use_batch_mode`` flag to :func:`.create_engine`:: + + engine = create_engine( + "postgresql+psycopg2://scott:tiger@host/dbname", + use_batch_mode=True) + +Batch mode is considered to be **experimental** at this time, however may +be enabled by default in a future release. + + +.. versionadded:: 1.2.0 + + + .. _psycopg2_unicode: Unicode with Psycopg2 @@ -510,6 +544,7 @@ class PGDialect_psycopg2(PGDialect): def __init__(self, server_side_cursors=False, use_native_unicode=True, client_encoding=None, use_native_hstore=True, use_native_uuid=True, + use_batch_mode=False, **kwargs): PGDialect.__init__(self, **kwargs) self.server_side_cursors = server_side_cursors @@ -518,6 +553,7 @@ class PGDialect_psycopg2(PGDialect): self.use_native_uuid = use_native_uuid self.supports_unicode_binds = use_native_unicode self.client_encoding = client_encoding + self.psycopg2_batch_mode = use_batch_mode if self.dbapi and hasattr(self.dbapi, '__version__'): m = re.match(r'(\d+)\.(\d+)(?:\.(\d+))?', self.dbapi.__version__) @@ -540,7 +576,8 @@ class PGDialect_psycopg2(PGDialect): # http://initd.org/psycopg/docs/news.html#what-s-new-in-psycopg-2-0-9 self.supports_sane_multi_rowcount = \ self.psycopg2_version >= \ - self.FEATURE_VERSION_MAP['sane_multi_rowcount'] + self.FEATURE_VERSION_MAP['sane_multi_rowcount'] and \ + not self.psycopg2_batch_mode @classmethod def dbapi(cls): @@ -638,6 +675,13 @@ class PGDialect_psycopg2(PGDialect): else: return None + def do_executemany(self, cursor, statement, parameters, context=None): + if self.psycopg2_batch_mode: + extras = self._psycopg2_extras() + extras.execute_batch(cursor, statement, parameters) + else: + cursor.executemany(statement, parameters) + @util.memoized_instancemethod def _hstore_oids(self, conn): if self.psycopg2_version >= self.FEATURE_VERSION_MAP['hstore_adapter']: |