pymongo

Version 3.9 adds support for MongoDB 4.2. Highlights include:

Support for MongoDB 4.2 sharded transactions. Sharded transactions have the same API as replica set transactions. See Transactions .

New method pymongo.client_session.ClientSession.with_transaction() to support conveniently running a transaction in a session with automatic retries and at-most-once semantics.

Initial support for client side field level encryption. See the docstring for MongoClient , AutoEncryptionOpts , and encryption for details. Note: Support for client side encryption is in beta. Backwards-breaking changes may be made before the final release.

Added the max_commit_time_ms parameter to start_transaction() .

Implement the URI options specification in the MongoClient() constructor. Consequently, there are a number of changes in connection options:

• The tlsInsecure option has been added.

• The tls option has been added. The older ssl option has been retained as an alias to the new tls option.

• wTimeout has been deprecated in favor of wTimeoutMS .

• wTimeoutMS now overrides wTimeout if the user provides both.

• j has been deprecated in favor of journal .

• journal now overrides j if the user provides both.

• ssl_cert_reqs has been deprecated in favor of tlsAllowInvalidCertificates . Instead of ssl.CERT_NONE , ssl.CERT_OPTIONAL and ssl.CERT_REQUIRED , the new option expects a boolean value - True is equivalent to ssl.CERT_NONE , while False is equivalent to ssl.CERT_REQUIRED .

• ssl_match_hostname has been deprecated in favor of tlsAllowInvalidHostnames .

• ssl_ca_certs has been deprecated in favor of tlsCAFile .

• ssl_certfile has been deprecated in favor of tlsCertificateKeyFile .

• ssl_pem_passphrase has been deprecated in favor of tlsCertificateKeyFilePassword .

• waitQueueMultiple has been deprecated without replacement. This option was a poor solution for putting an upper bound on queuing since it didn’t affect queuing in other parts of the driver.

The retryWrites URI option now defaults to True . Supported write operations that fail with a retryable error will automatically be retried one time, with at-most-once semantics.

Support for retryable reads and the retryReads URI option which is enabled by default. See the MongoClient documentation for details. Now that supported operations are retried automatically and transparently, users should consider adjusting any custom retry logic to prevent an application from inadvertently retrying for too long.

Support zstandard for wire protocol compression.

Support for periodically polling DNS SRV records to update the mongos proxy list without having to change client configuration.

New method pymongo.database.Database.aggregate() to support running database level aggregations.

Support for publishing Connection Monitoring and Pooling events via the new ConnectionPoolListener class. See monitoring for an example.

pymongo.collection.Collection.aggregate() and pymongo.database.Database.aggregate() now support the $merge pipeline stage and use read preference PRIMARY if the $out or $merge pipeline stages are used.

Support for specifying a pipeline or document in update_one() , update_many() , find_one_and_update() , UpdateOne() , and UpdateMany() .

New BSON utility functions encode() and decode()

Binary now supports any bytes-like type that implements the buffer protocol.

Resume tokens can now be accessed from a ChangeStream cursor using the resume_token attribute.

Connections now survive primary step-down when using MongoDB 4.2+. Applications should expect less socket connection turnover during replica set elections.

Unavoidable breaking changes:

• Applications that use MongoDB with the MMAPv1 storage engine must now explicitly disable retryable writes via the connection string (e.g. MongoClient("mongodb://my.mongodb.cluster/db?retryWrites=false") ) or the MongoClient constructor’s keyword argument (e.g. MongoClient("mongodb://my.mongodb.cluster/db", retryWrites=False) ) to avoid running into OperationFailure exceptions during write operations. The MMAPv1 storage engine is deprecated and does not support retryable writes which are now turned on by default.

• In order to ensure that the connectTimeoutMS URI option is honored when connecting to clusters with a mongodb+srv:// connection string, the minimum required version of the optional dnspython dependency has been bumped to 1.16.0. This is a breaking change for applications that use PyMongo’s SRV support with a version of dnspython older than 1.16.0.

Issues Resolved

See the PyMongo 3.9 release notes in JIRA for the list of resolved issues in this release.

Warning

PyMongo no longer supports Python 2.6. RHEL 6 users should install Python 2.7 or newer from Red Hat Software Collections . CentOS 6 users should install Python 2.7 or newer from SCL

Warning

PyMongo no longer supports PyPy3 versions older than 3.5. Users must upgrade to PyPy3.5+.

• ObjectId now implements the ObjectID specification version 0.2 .

• For better performance and to better follow the GridFS spec, GridOut now uses a single cursor to read all the chunks in the file. Previously, each chunk in the file was queried individually using find_one() .

• gridfs.grid_file.GridOut.read() now only checks for extra chunks after reading the entire file. Previously, this method would check for extra chunks on every call.

• current_op() now always uses the Database ’s codec_options when decoding the command response. Previously the codec_options was only used when the MongoDB server version was <= 3.0.

• Undeprecated get_default_database() and added the default parameter.

• TLS Renegotiation is now disabled when possible.

• Custom types can now be directly encoded to, and decoded from MongoDB using the TypeCodec and TypeRegistry APIs. For more information, see the custom type example .

• Attempting a multi-document transaction on a sharded cluster now raises a ConfigurationError .

• pymongo.cursor.Cursor.distinct() and pymongo.cursor.Cursor.count() now send the Cursor’s comment() as the “comment” top-level command option instead of “$comment”. Also, note that “comment” must be a string.

• Add the filter parameter to list_collection_names() .

• Changes can now be requested from a ChangeStream cursor without blocking indefinitely using the new pymongo.change_stream.ChangeStream.try_next() method.

• Fixed a reference leak bug when splitting a batched write command based on maxWriteBatchSize or the max message size.

• Deprecated running find queries that set min() and/or max() but do not also set a hint() of which index to use. The find command is expected to require a hint() when using min/max starting in MongoDB 4.2.

• Documented support for the uuidRepresentation URI option, which has been supported since PyMongo 2.7. Valid values are pythonLegacy (the default), javaLegacy , csharpLegacy and standard . New applications should consider setting this to standard for cross language compatibility.

• RawBSONDocument now validates that the bson_bytes passed in represent a single bson document. Earlier versions would mistakenly accept multiple bson documents.

• Iterating over a RawBSONDocument now maintains the same field order of the underlying raw BSON document.

• Applications can now register a custom server selector. For more information see the server selector example .

• The connection pool now implements a LIFO policy.

Unavoidable breaking changes:

• In order to follow the ObjectID Spec version 0.2, an ObjectId’s 3-byte machine identifier and 2-byte process id have been replaced with a single 5-byte random value generated per process. This is a breaking change for any application that attempts to interpret those bytes.

Issues Resolved

See the PyMongo 3.8 release notes in JIRA for the list of resolved issues in this release.

Version 3.7.2 fixes a few issues discovered since the release of 3.7.1.

• Fixed a bug in retryable writes where a previous command’s “txnNumber” field could be sent leading to incorrect results.

• Fixed a memory leak of a few bytes on some insert, update, or delete commands when running against MongoDB 3.6+.

• Fixed a bug that caused pymongo.collection.Collection.ensure_index() to only cache a single index per database.

• Updated the documentation examples to use pymongo.collection.Collection.count_documents() instead of pymongo.collection.Collection.count() and pymongo.cursor.Cursor.count() .

Issues Resolved

See the PyMongo 3.7.2 release notes in JIRA for the list of resolved issues in this release.

Version 3.7.1 fixes a few issues discovered since the release of 3.7.0.

• Calling authenticate() more than once with the same credentials results in OperationFailure.

• Authentication fails when SCRAM-SHA-1 is used to authenticate users with only MONGODB-CR credentials.

• A millisecond rounding problem when decoding datetimes in the pure Python BSON decoder on 32 bit systems and AWS lambda.

Issues Resolved

See the PyMongo 3.7.1 release notes in JIRA for the list of resolved issues in this release.

Version 3.7 adds support for MongoDB 4.0. Highlights include:

• Support for single replica set multi-document ACID transactions. See Transactions .

• Support for wire protocol compression. See the MongoClient() documentation for details.

• Support for Python 3.7.

• New count methods, count_documents() and estimated_document_count() . count_documents() is always accurate when used with MongoDB 3.6+, or when used with older standalone or replica set deployments. With older sharded clusters is it always accurate when used with Primary read preference. It can also be used in a transaction, unlike the now deprecated pymongo.collection.Collection.count() and pymongo.cursor.Cursor.count() methods.

• Support for watching changes on all collections in a database using the new pymongo.database.Database.watch() method.

• Support for watching changes on all collections in all databases using the new pymongo.mongo_client.MongoClient.watch() method.

• Support for watching changes starting at a user provided timestamp using the new start_at_operation_time parameter for the watch() helpers.

• Better support for using PyMongo in a FIPS 140-2 environment. Specifically, the following features and changes allow PyMongo to function when MD5 support is disabled in OpenSSL by the FIPS Object Module:

• Support for the SCRAM-SHA-256 authentication mechanism. The GSSAPI , PLAIN , and MONGODB-X509 mechanisms can also be used to avoid issues with OpenSSL in FIPS environments.

• MD5 checksums are now optional in GridFS. See the disable_md5 option of GridFS and GridFSBucket .

• ObjectId machine bytes are now hashed using FNV-1a instead of MD5.

• The list_collection_names() and collection_names() methods use the nameOnly option when supported by MongoDB.

• The pymongo.collection.Collection.watch() method now returns an instance of the CollectionChangeStream class which is a subclass of ChangeStream .

• SCRAM client and server keys are cached for improved performance, following RFC 5802 .

• If not specified, the authSource for the PLAIN authentication mechanism defaults to $external.

• wtimeoutMS is once again supported as a URI option.

• When using unacknowledged write concern and connected to MongoDB server version 3.6 or greater, the bypass_document_validation option is now supported in the following write helpers: insert_one() , replace_one() , update_one() , update_many() .

Deprecations:

• Deprecated pymongo.collection.Collection.count() and pymongo.cursor.Cursor.count() . These two methods use the count command and may or may not be accurate , depending on the options used and connected MongoDB topology. Use count_documents() instead.

• Deprecated the snapshot option of find() and find_one() . The option was deprecated in MongoDB 3.6 and removed in MongoDB 4.0.

• Deprecated the max_scan option of find() and find_one() . The option was deprecated in MongoDB 4.0. Use maxTimeMS instead.

• Deprecated close_cursor() . Use close() instead.

• Deprecated database_names() . Use list_database_names() instead.

• Deprecated collection_names() . Use list_collection_names() instead.

• Deprecated parallel_scan() . MongoDB 4.2 will remove the parallelCollectionScan command.

Unavoidable breaking changes:

• Commands that fail with server error codes 10107, 13435, 13436, 11600, 11602, 189, 91 (NotMaster, NotMasterNoSlaveOk, NotMasterOrSecondary, InterruptedAtShutdown, InterruptedDueToReplStateChange, PrimarySteppedDown, ShutdownInProgress respectively) now always raise NotMasterError instead of OperationFailure .

• parallel_scan() no longer uses an implicit session. Explicit sessions are still supported.

• Unacknowledged writes ( w=0 ) with an explicit session parameter now raise a client side error. Since PyMongo does not wait for a response for an unacknowledged write, two unacknowledged writes run serially by the client may be executed simultaneously on the server. However, the server requires a single session must not be used simultaneously by more than one operation. Therefore explicit sessions cannot support unacknowledged writes. Unacknowledged writes without a session parameter are still supported.

Issues Resolved

See the PyMongo 3.7 release notes in JIRA for the list of resolved issues in this release.

Version 3.6.1 fixes bugs reported since the release of 3.6.0:

• Fix regression in PyMongo 3.5.0 that causes idle sockets to be closed almost instantly when maxIdleTimeMS is set. Idle sockets are now closed after maxIdleTimeMS milliseconds.

• pymongo.mongo_client.MongoClient.max_idle_time_ms now returns milliseconds instead of seconds.

• Properly import and use the monotonic library for monotonic time when it is installed.

• aggregate() now ignores the batchSize argument when running a pipeline with a $out stage.

• Always send handshake metadata for new connections.

Issues Resolved

See the PyMongo 3.6.1 release notes in JIRA for the list of resolved issues in this release.

Version 3.6 adds support for MongoDB 3.6, drops support for CPython 3.3 (PyPy3 is still supported), and drops support for MongoDB versions older than 2.6. If connecting to a MongoDB 2.4 server or older, PyMongo now throws a ConfigurationError .

Highlights include:

• Support for change streams. See the watch() method for details.

• Support for array_filters in update_one() , update_many() , find_one_and_update() , UpdateOne() , and UpdateMany() .

• New Session API, see start_session() .

• New methods find_raw_batches() and aggregate_raw_batches() for use with external libraries that can parse raw batches of BSON data.

• New methods list_databases() and list_database_names() .

• New methods list_collections() and list_collection_names() .

• Support for mongodb+srv:// URIs. See MongoClient for details.

• Index management helpers ( create_index() , create_indexes() , drop_index() , drop_indexes() , reindex() ) now support maxTimeMS.

• Support for retryable writes and the retryWrites URI option. See MongoClient for details.

Deprecations:

• The useCursor option for aggregate() is deprecated. The option was only necessary when upgrading from MongoDB 2.4 to MongoDB 2.6. MongoDB 2.4 is no longer supported.

• The add_user() and remove_user() methods are deprecated. See the method docstrings for alternatives.

Unavoidable breaking changes:

• Starting in MongoDB 3.6, the deprecated methods authenticate() and logout() now invalidate all cursors created prior. Instead of using these methods to change credentials, pass credentials for one user to the MongoClient at construction time, and either grant access to several databases to one user account, or use a distinct client object for each user.

• BSON binary subtype 4 is decoded using RFC-4122 byte order regardless of the UUID representation. This is a change in behavior for applications that use UUID representation bson.binary.JAVA_LEGACY or bson.binary.CSHARP_LEGACY to decode BSON binary subtype 4. Other UUID representations, bson.binary.PYTHON_LEGACY (the default) and bson.binary.STANDARD , and the decoding of BSON binary subtype 3 are unchanged.

Issues Resolved

See the PyMongo 3.6 release notes in JIRA for the list of resolved issues in this release.

Version 3.5.1 fixes bugs reported since the release of 3.5.0:

• Work around socket.getsockopt issue with NetBSD.

• pymongo.command_cursor.CommandCursor.close() now closes the cursor synchronously instead of deferring to a background thread.

• Fix documentation build warnings with Sphinx 1.6.x.

Issues Resolved

See the PyMongo 3.5.1 release notes in JIRA for the list of resolved issues in this release.

Version 3.5 implements a number of improvements and bug fixes:

Highlights include:

• Username and password can be passed to ~pymongo.mongo_client.MongoClient as keyword arguments. Before, the only way to pass them was in the URI.

• Increased the performance of using ~bson.raw_bson.RawBSONDocument.

• Increased the performance of ~pymongo.mongo_client.MongoClient.database_names by using the nameOnly option for listDatabases when available.

• Increased the performance of ~pymongo.collection.Collection.bulk_write by reducing the memory overhead of ~pymongo.operations.InsertOne, ~pymongo.operations.DeleteOne, and ~pymongo.operations.DeleteMany.

• Added the collation option to ~pymongo.operations.DeleteOne, ~pymongo.operations.DeleteMany, ~pymongo.operations.ReplaceOne, ~pymongo.operations.UpdateOne, and ~pymongo.operations.UpdateMany.

• Implemented the MongoDB Extended JSON specification.

• ~bson.decimal128.Decimal128 now works when cdecimal is installed.

• PyMongo is now tested against a wider array of operating systems and CPU architectures (including s390x, ARM64, and POWER8).

Changes and Deprecations:

• ~pymongo.collection.Collection.find has new options return_key, show_record_id, snapshot, hint, max_time_ms, max_scan, min, max, and comment. Deprecated the option modifiers.

• Deprecated ~pymongo.collection.Collection.group. The group command was deprecated in MongoDB 3.4 and is expected to be removed in MongoDB 3.6. Applications should use ~pymongo.collection.Collection.aggregate with the $group pipeline stage instead.

• Deprecated ~pymongo.database.Database.authenticate. Authenticating multiple users conflicts with support for logical sessions in MongoDB 3.6. To authenticate as multiple users, create multiple instances of ~pymongo.mongo_client.MongoClient.

• Deprecated ~pymongo.database.Database.eval. The eval command was deprecated in MongoDB 3.0 and will be removed in a future server version.

• Deprecated ~pymongo.database.SystemJS.

• Deprecated ~pymongo.mongo_client.MongoClient.get_default_database. Applications should use ~pymongo.mongo_client.MongoClient.get_database without the `name` parameter instead.

• Deprecated the MongoClient option socketKeepAlive`. It now defaults to true and disabling it is not recommended, see does TCP keepalive time affect MongoDB Deployments?

• Deprecated ~pymongo.collection.Collection.initialize_ordered_bulk_op, ~pymongo.collection.Collection.initialize_unordered_bulk_op, and ~pymongo.bulk.BulkOperationBuilder. Use ~pymongo.collection.Collection.bulk_write instead.

• Deprecated ~bson.json_util.STRICT_JSON_OPTIONS. Use ~bson.json_util.RELAXED_JSON_OPTIONS or ~bson.json_util.CANONICAL_JSON_OPTIONS instead.

• If a custom ~bson.codec_options.CodecOptions is passed to RawBSONDocument, its document_class` must be RawBSONDocument.

• ~pymongo.collection.Collection.list_indexes no longer raises OperationFailure when the collection (or database) does not exist on MongoDB >= 3.0. Instead, it returns an empty ~pymongo.command_cursor.CommandCursor to make the behavior consistent across all MongoDB versions.

• In Python 3, ~bson.json_util.loads now automatically decodes JSON $binary with a subtype of 0 into bytes instead of ~bson.binary.Binary.

• ~bson.json_util.loads now raises TypeError or ValueError when parsing JSON type wrappers with values of the wrong type or any extra keys.

• pymongo.cursor.Cursor.close and pymongo.mongo_client.MongoClient.close now kill cursors synchronously instead of deferring to a background thread.

• ~pymongo.uri_parser.parse_uri now returns the original value of the readPreference MongoDB URI option instead of the validated read preference mode.

Issues Resolved

See the PyMongo 3.5 release notes in JIRA for the list of resolved issues in this release.

Version 3.4 implements the new server features introduced in MongoDB 3.4 and a whole lot more:

Highlights include:

• Complete support for MongoDB 3.4:

  • Unicode aware string comparison using Collation.

  • Support for the new ~bson.decimal128.Decimal128 BSON type.

  • A new maxStalenessSeconds read preference option.

  • A username is no longer required for the MONGODB-X509 authentication mechanism when connected to MongoDB >= 3.4.

  • ~pymongo.collection.Collection.parallel_scan supports maxTimeMS.

  • ~pymongo.write_concern.WriteConcern is automatically applied by all helpers for commands that write to the database when connected to MongoDB 3.4+. This change affects the following helpers:

    • ~pymongo.mongo_client.MongoClient.drop_database

    • ~pymongo.database.Database.create_collection

    • ~pymongo.database.Database.drop_collection

    • ~pymongo.collection.Collection.aggregate (when using $out)

    • ~pymongo.collection.Collection.create_indexes

    • ~pymongo.collection.Collection.create_index

    • ~pymongo.collection.Collection.drop_indexes

    • ~pymongo.collection.Collection.drop_indexes

    • ~pymongo.collection.Collection.drop_index

    • ~pymongo.collection.Collection.map_reduce (when output is not "inline")

    • ~pymongo.collection.Collection.reindex

    • ~pymongo.collection.Collection.rename

• Improved support for logging server discovery and monitoring events. See ~pymongo.monitoring for examples.

• Support for matching iPAddress subjectAltName values for TLS certificate verification.

• TLS compression is now explicitly disabled when possible.

• The Server Name Indication (SNI) TLS extension is used when possible.

• Finer control over JSON encoding/decoding with ~bson.json_util.JSONOptions.

• Allow ~bson.code.Code objects to have a scope of None, signifying no scope. Also allow encoding Code objects with an empty scope (i.e. {}).

Warning

Starting in PyMongo 3.4, bson.code.Code.scope may return None, as the default scope is None instead of {}.

Note

PyMongo 3.4+ attempts to create sockets non-inheritable when possible (i.e. it sets the close-on-exec flag on socket file descriptors). Support is limited to a subset of POSIX operating systems (not including Windows) and the flag usually cannot be set in a single atomic operation. CPython 3.4+ implements PEP 446, creating all file descriptors non-inheritable by default. Users that require this behavior are encouraged to upgrade to CPython 3.4+.

Since 3.4rc0, the max staleness option has been renamed from maxStalenessMS to maxStalenessSeconds, its smallest value has changed from twice heartbeatFrequencyMS to 90 seconds, and its default value has changed from None or 0 to -1.

Issues Resolved

See the PyMongo 3.4 release notes in JIRA for the list of resolved issues in this release.

Version 3.3.1 fixes a memory leak when decoding elements inside of a RawBSONDocument .

Issues Resolved

See the PyMongo 3.3.1 release notes in Jira for the list of resolved issues in this release.

Version 3.3 adds the following major new features:

• C extensions support on big endian systems.

• Kerberos authentication support on Windows using WinKerberos.

• A new ssl_clrfile option to support certificate revocation lists.

• A new ssl_pem_passphrase option to support encrypted key files.

• Support for publishing server discovery and monitoring events. See ~pymongo.monitoring for details.

• New connection pool options minPoolSize and maxIdleTimeMS.

• New heartbeatFrequencyMS option controls the rate at which background monitoring threads re-check servers. Default is once every 10 seconds.

Warning

PyMongo 3.3 drops support for MongoDB versions older than 2.4. It also drops support for python 3.2 (pypy3 continues to be supported).

Issues Resolved

See the PyMongo 3.3 release notes in JIRA for the list of resolved issues in this release.

Version 3.2.2 fixes a few issues reported since the release of 3.2.1, including a fix for using the connect option in the MongoDB URI and support for setting the batch size for a query to 1 when using MongoDB 3.2+.

Issues Resolved

See the PyMongo 3.2.2 release notes in JIRA for the list of resolved issues in this release.

Version 3.2.1 fixes a few issues reported since the release of 3.2, including running the mapreduce command twice when calling the inline_map_reduce() method and a TypeError being raised when calling download_to_stream() . This release also improves error messaging around BSON decoding.

Issues Resolved

See the PyMongo 3.2.1 release notes in JIRA for the list of resolved issues in this release.

Version 3.2 implements the new server features introduced in MongoDB 3.2.

Highlights include:

• Full support for MongoDB 3.2 including:

• Support for ReadConcern

• WriteConcern is now applied to find_one_and_replace() , find_one_and_update() , and find_one_and_delete() .

• Support for the new bypassDocumentValidation option in write helpers.

• Support for reading and writing raw BSON with RawBSONDocument

Note

Certain MongoClient properties now block until a connection is established or raise ServerSelectionTimeoutError if no server is available. See MongoClient for details.

Issues Resolved

See the PyMongo 3.2 release notes in JIRA for the list of resolved issues in this release.

Version 3.1.1 fixes a few issues reported since the release of 3.1, including a regression in error handling for oversize command documents and interrupt handling issues in the C extensions.

Issues Resolved

See the PyMongo 3.1.1 release notes in JIRA for the list of resolved issues in this release.

Version 3.1 implements a few new features and fixes bugs reported since the release of 3.0.3.

Highlights include:

• Command monitoring support. See monitoring for details.

• Configurable error handling for UnicodeDecodeError . See the unicode_decode_error_handler option of CodecOptions .

• Optional automatic timezone conversion when decoding BSON datetime. See the tzinfo option of CodecOptions .

• An implementation of GridFSBucket from the new GridFS spec.

• Compliance with the new Connection String spec.

• Reduced idle CPU usage in Python 2.

Changes in internal classes

The private PeriodicExecutor class no longer takes a condition_class option, and the private thread_util.Event class is removed.

Issues Resolved

See the PyMongo 3.1 release notes in JIRA for the list of resolved issues in this release.

Version 3.0.3 fixes issues reported since the release of 3.0.2, including a feature breaking bug in the GSSAPI implementation.

Issues Resolved

See the PyMongo 3.0.3 release notes in JIRA for the list of resolved issues in this release.

Version 3.0.2 fixes issues reported since the release of 3.0.1, most importantly a bug that could route operations to replica set members that are not in primary or secondary state when using PrimaryPreferred or Nearest . It is a recommended upgrade for all users of PyMongo 3.0.x.

Issues Resolved

See the PyMongo 3.0.2 release notes in JIRA for the list of resolved issues in this release.

Version 3.0.1 fixes issues reported since the release of 3.0, most importantly a bug in GridFS.delete that could prevent file chunks from actually being deleted.

Issues Resolved

See the PyMongo 3.0.1 release notes in JIRA for the list of resolved issues in this release.

PyMongo 3.0 is a partial rewrite of PyMongo bringing a large number of improvements:

• A unified client class. MongoClient is the one and only client class for connecting to a standalone mongod, replica set, or sharded cluster. Migrating from a standalone, to a replica set, to a sharded cluster can be accomplished with only a simple URI change.

• MongoClient is much more responsive to configuration changes in your MongoDB deployment. All connected servers are monitored in a non-blocking manner. Slow to respond or down servers no longer block server discovery, reducing application startup time and time to respond to new or reconfigured servers and replica set failovers.

• A unified CRUD API. All official MongoDB drivers now implement a standard CRUD API allowing polyglot developers to move from language to language with ease.

• Single source support for Python 2.x and 3.x. PyMongo no longer relies on 2to3 to support Python 3.

• A rewritten pure Python BSON implementation, improving performance with pypy and cpython deployments without support for C extensions.

• Better support for greenlet based async frameworks including eventlet.

• Immutable client, database, and collection classes, avoiding a host of thread safety issues in client applications.

PyMongo 3.0 brings a large number of API changes. Be sure to read the changes listed below before upgrading from PyMongo 2.x.

Warning

PyMongo no longer supports Python 2.4, 2.5, or 3.1. If you must use PyMongo with these versions of Python the 2.x branch of PyMongo will be minimally supported for some time.

SONManipulator changes

The SONManipulator API has limitations as a technique for transforming your data. Instead, it is more flexible and straightforward to transform outgoing documents in your own code before passing them to PyMongo, and transform incoming documents after receiving them from PyMongo.

Thus the add_son_manipulator() method is deprecated. PyMongo 3’s new CRUD API does not apply SON manipulators to documents passed to bulk_write() , insert_one() , insert_many() , update_one() , or update_many() . SON manipulators are not applied to documents returned by the new methods find_one_and_delete() , find_one_and_replace() , and find_one_and_update() .

SSL/TLS changes

When ssl is True the ssl_cert_reqs option now defaults to ssl.CERT_REQUIRED if not provided. PyMongo will attempt to load OS provided CA certificates to verify the server, raising ConfigurationError if it cannot.

Gevent Support

In previous versions, PyMongo supported Gevent in two modes: you could call gevent.monkey.patch_socket() and pass use_greenlets=True to MongoClient , or you could simply call gevent.monkey.patch_all() and omit the use_greenlets argument.

In PyMongo 3.0, the use_greenlets option is gone. To use PyMongo with Gevent simply call gevent.monkey.patch_all() .

For more information, see PyMongo’s Gevent documentation .

MongoClient changes

MongoClient is now the one and only client class for a standalone server, mongos, or replica set. It includes the functionality that had been split into MongoReplicaSetClient : it can connect to a replica set, discover all its members, and monitor the set for stepdowns, elections, and reconfigs. MongoClient now also supports the full ReadPreference API.

The obsolete classes MasterSlaveConnection , Connection , and ReplicaSetConnection are removed.

The MongoClient constructor no longer blocks while connecting to the server or servers, and it no longer raises ConnectionFailure if they are unavailable, nor ConfigurationError if the user’s credentials are wrong. Instead, the constructor returns immediately and launches the connection process on background threads. The connect option is added to control whether these threads are started immediately, or when the client is first used.

Therefore the alive method is removed since it no longer provides meaningful information; even if the client is disconnected, it may discover a server in time to fulfill the next operation.

In PyMongo 2.x, MongoClient accepted a list of standalone MongoDB servers and used the first it could connect to:

MongoClient ([ 'host1.com:27017' , 'host2.com:27017' ])

A list of multiple standalones is no longer supported; if multiple servers are listed they must be members of the same replica set, or mongoses in the same sharded cluster.

The behavior for a list of mongoses is changed from “high availability” to “load balancing”. Before, the client connected to the lowest-latency mongos in the list, and used it until a network error prompted it to re-evaluate all mongoses’ latencies and reconnect to one of them. In PyMongo 3, the client monitors its network latency to all the mongoses continuously, and distributes operations evenly among those with the lowest latency. See mongos Load Balancing for more information.

The client methods start_request , in_request , and end_request are removed, and so is the auto_start_request option. Requests were designed to make read-your-writes consistency more likely with the w=0 write concern. Additionally, a thread in a request used the same member for all secondary reads in a replica set. To ensure read-your-writes consistency in PyMongo 3.0, do not override the default write concern with w=0 , and do not override the default read preference of PRIMARY.

Support for the slaveOk (or slave_okay ), safe , and network_timeout options has been removed. Use SECONDARY_PREFERRED instead of slave_okay. Accept the default write concern, acknowledged writes, instead of setting safe=True. Use socketTimeoutMS in place of network_timeout (note that network_timeout was in seconds, where as socketTimeoutMS is milliseconds).

The max_pool_size option has been removed. It is replaced by the maxPoolSize MongoDB URI option. maxPoolSize is now a supported URI option in PyMongo and can be passed as a keyword argument.

The copy_database method is removed, see the copy_database examples for alternatives.

The disconnect method is removed. Use close() instead.

The get_document_class method is removed. Use codec_options instead.

The get_lasterror_options , set_lasterror_options , and unset_lasterror_options methods are removed. Write concern options can be passed to MongoClient as keyword arguments or MongoDB URI options.

The get_database() method is added for getting a Database instance with its options configured differently than the MongoClient’s.

The following read-only attributes have been added:

• codec_options

The following attributes are now read-only:

• read_preference

• write_concern

The following attributes have been removed:

• document_class (use codec_options instead)

• host (use address instead)

• min_wire_version

• max_wire_version

• port (use address instead)

• safe (use write_concern instead)

• slave_okay (use read_preference instead)

• tag_sets (use read_preference instead)

• tz_aware (use codec_options instead)

The following attributes have been renamed:

• secondary_acceptable_latency_ms is now local_threshold_ms and is now read-only.

Cursor changes

The conn_id property is renamed to address .

Cursor management changes

CursorManager and set_cursor_manager() are no longer deprecated. If you subclass CursorManager your implementation of close() must now take a second parameter, address . The BatchCursorManager class is removed.

The second parameter to close_cursor() is renamed from _conn_id to address . kill_cursors() now accepts an address parameter.

Database changes

The connection property is renamed to client .

The following read-only attributes have been added:

• codec_options

The following attributes are now read-only:

• read_preference

• write_concern

Use get_database() for getting a Database instance with its options configured differently than the MongoClient’s.

The following attributes have been removed:

• safe

• secondary_acceptable_latency_ms

• slave_okay

• tag_sets

The following methods have been added:

• get_collection()

The following methods have been changed:

• command() . Support for as_class , uuid_subtype , tag_sets , and secondary_acceptable_latency_ms have been removed. You can instead pass an instance of CodecOptions as codec_options and an instance of a read preference class from read_preferences as read_preference . The fields and compile_re options are also removed. The fields options was undocumented and never really worked. Regular expressions are always decoded to Regex .

The following methods have been deprecated:

• add_son_manipulator()

The following methods have been removed:

The get_lasterror_options , set_lasterror_options , and unset_lasterror_options methods have been removed. Use WriteConcern with get_database() instead.

Collection changes

The following read-only attributes have been added:

• codec_options

The following attributes are now read-only:

• read_preference

• write_concern

Use get_collection() or with_options() for getting a Collection instance with its options configured differently than the Database’s.

The following attributes have been removed:

• safe

• secondary_acceptable_latency_ms

• slave_okay

• tag_sets

The following methods have been added:

• bulk_write()

• insert_one()

• insert_many()

• update_one()

• update_many()

• replace_one()

• delete_one()

• delete_many()

• find_one_and_delete()

• find_one_and_replace()

• find_one_and_update()

• with_options()

• create_indexes()

• list_indexes()

The following methods have changed:

• aggregate() now always returns an instance of CommandCursor . See the documentation for all options.

• count() now optionally takes a filter argument, as well as other options supported by the count command.

• distinct() now optionally takes a filter argument.

• create_index() no longer caches indexes, therefore the cache_for parameter has been removed. It also no longer supports the bucket_size and drop_dups aliases for bucketSize and dropDups .

The following methods are deprecated:

• save()

• insert()

• update()

• remove()

• find_and_modify()

• ensure_index()

The following methods have been removed:

The get_lasterror_options , set_lasterror_options , and unset_lasterror_options methods have been removed. Use WriteConcern with with_options() instead.

Changes to find() and find_one()

The following find/find_one options have been renamed:

These renames only affect your code if you passed these as keyword arguments, like find(fields=[‘fieldname’]). If you passed only positional parameters these changes are not significant for your application.

• spec -> filter

• fields -> projection

• partial -> allow_partial_results

The following find/find_one options have been added:

• cursor_type (see CursorType for values)

• oplog_replay

• modifiers

The following find/find_one options have been removed:

• network_timeout (use max_time_ms() instead)

• slave_okay (use one of the read preference classes from read_preferences and with_options() instead)

• read_preference (use with_options() instead)

• tag_sets (use one of the read preference classes from read_preferences and with_options() instead)

• secondary_acceptable_latency_ms (use the localThresholdMS URI option instead)

• max_scan (use the new modifiers option instead)

• snapshot (use the new modifiers option instead)

• tailable (use the new cursor_type option instead)

• await_data (use the new cursor_type option instead)

• exhaust (use the new cursor_type option instead)

• as_class (use with_options() with CodecOptions instead)

• compile_re (BSON regular expressions are always decoded to Regex )

The following find/find_one options are deprecated:

• manipulate

The following renames need special handling.

• timeout -> no_cursor_timeout - The default for timeout was True. The default for no_cursor_timeout is False. If you were previously passing False for timeout you must pass True for no_cursor_timeout to keep the previous behavior.

errors changes

The exception classes UnsupportedOption and TimeoutError are deleted.

gridfs changes

Since PyMongo 1.6, methods open and close of GridFS raised an UnsupportedAPI exception, as did the entire GridFile class. The unsupported methods, the class, and the exception are all deleted.

bson changes

The compile_re option is removed from all methods that accepted it in bson and json_util . Additionally, it is removed from find() , find_one() , aggregate() , command() , and so on. PyMongo now always represents BSON regular expressions as Regex objects. This prevents errors for incompatible patterns, see PYTHON-500 . Use try_compile() to attempt to convert from a BSON regular expression to a Python regular expression object.

PyMongo now decodes the int64 BSON type to Int64 , a trivial wrapper around long (in python 2.x) or int (in python 3.x). This allows BSON int64 to be round tripped without losing type information in python 3. Note that if you store a python long (or a python int larger than 4 bytes) it will be returned from PyMongo as Int64 .

The as_class , tz_aware , and uuid_subtype options are removed from all BSON encoding and decoding methods. Use CodecOptions to configure these options. The APIs affected are:

• decode_all()

• decode_iter()

• decode_file_iter()

• encode()

• decode()

This is a breaking change for any application that uses the BSON API directly and changes any of the named parameter defaults. No changes are required for applications that use the default values for these options. The behavior remains the same.

Issues Resolved

See the PyMongo 3.0 release notes in JIRA for the list of resolved issues in this release.

Version 2.9.5 works around ssl module deprecations in Python 3.6, and expected future ssl module deprecations. It also fixes bugs found since the release of 2.9.4.

• Use ssl.SSLContext and ssl.PROTOCOL_TLS_CLIENT when available.

• Fixed a C extensions build issue when the interpreter was built with -std=c99

• Fixed various build issues with MinGW32.

• Fixed a write concern bug in add_user() and remove_user() when connected to MongoDB 3.2+

• Fixed various test failures related to changes in gevent, MongoDB, and our CI test environment.

Issues Resolved

See the PyMongo 2.9.5 release notes in JIRA for the list of resolved issues in this release.

Version 2.9.4 fixes issues reported since the release of 2.9.3.

• Fixed repr for closed instances of MongoClient .

• Fixed MongoReplicaSetClient handling of uuidRepresentation.

• Fixed building and testing the documentation with python 3.x.

• New documentation for TLS/SSL and PyMongo and Using PyMongo with MongoDB Atlas .

Issues Resolved

See the PyMongo 2.9.4 release notes in JIRA for the list of resolved issues in this release.

Version 2.9.3 fixes a few issues reported since the release of 2.9.2 including thread safety issues in ensure_index() , drop_index() , and drop_indexes() .

Issues Resolved

See the PyMongo 2.9.3 release notes in JIRA for the list of resolved issues in this release.

Version 2.9.2 restores Python 3.1 support, which was broken in PyMongo 2.8. It improves an error message when decoding BSON as well as fixes a couple other issues including aggregate() ignoring codec_options and command() raising a superfluous DeprecationWarning .

Issues Resolved

See the PyMongo 2.9.2 release notes in JIRA for the list of resolved issues in this release.

Version 2.9.1 fixes two interrupt handling issues in the C extensions and adapts a test case for a behavior change in MongoDB 3.2.

Issues Resolved

See the PyMongo 2.9.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.9 provides an upgrade path to PyMongo 3.x. Most of the API changes from PyMongo 3.0 have been backported in a backward compatible way, allowing applications to be written against PyMongo >= 2.9, rather then PyMongo 2.x or PyMongo 3.x. See the PyMongo 3 Migration Guide for detailed examples.

Note

There are a number of new deprecations in this release for features that were removed in PyMongo 3.0. MongoClient :

• host

• port

• use_greenlets

• document_class

• tz_aware

• secondary_acceptable_latency_ms

• tag_sets

• uuid_subtype

• disconnect()

• alive() MongoReplicaSetClient :

• use_greenlets

• document_class

• tz_aware

• secondary_acceptable_latency_ms

• tag_sets

• uuid_subtype

• alive() Database :

• secondary_acceptable_latency_ms

• tag_sets

• uuid_subtype Collection :

• secondary_acceptable_latency_ms

• tag_sets

• uuid_subtype

Warning

In previous versions of PyMongo, changing the value of document_class changed the behavior of all existing instances of Collection :

coll = client . test . test >>> coll . find_one () {u'_id': ObjectId('5579dc7cfba5220cc14d9a18')} >>> from bson.son import SON >>> client . document_class = SON >>> coll . find_one () SON([(u'_id', ObjectId('5579dc7cfba5220cc14d9a18'))])

The document_class setting is now configurable at the client, database, collection, and per-operation level. This required breaking the existing behavior. To change the document class per operation in a forward compatible way use with_options() :

coll . find_one () {u'_id': ObjectId('5579dc7cfba5220cc14d9a18')} >>> from bson.codec_options import CodecOptions >>> coll . with_options ( CodecOptions ( SON )) . find_one () SON([(u'_id', ObjectId('5579dc7cfba5220cc14d9a18'))])

Issues Resolved

See the PyMongo 2.9 release notes in JIRA for the list of resolved issues in this release.

Version 2.8.1 fixes a number of issues reported since the release of PyMongo 2.8. It is a recommended upgrade for all users of PyMongo 2.x.

Issues Resolved

See the PyMongo 2.8.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.8 is a major release that provides full support for MongoDB 3.0 and fixes a number of bugs.

Special thanks to Don Mitchell, Ximing, Can Zhang, Sergey Azovskov, and Heewa Barfchin for their contributions to this release.

Highlights include:

• Support for the SCRAM-SHA-1 authentication mechanism (new in MongoDB 3.0).

• JSON decoder support for the new $numberLong and $undefined types.

• JSON decoder support for the $date type as an ISO-8601 string.

• Support passing an index name to hint() .

• The count() method will use a hint if one has been provided through hint() .

• A new socketKeepAlive option for the connection pool.

• New generator based BSON decode functions, decode_iter() and decode_file_iter() .

• Internal changes to support alternative storage engines like wiredtiger.

Note

There are a number of deprecations in this release for features that will be removed in PyMongo 3.0. These include:

• start_request()

• in_request()

• end_request()

• copy_database()

• error()

• last_status()

• previous_error()

• reset_error_history()

• MasterSlaveConnection

The JSON format for Timestamp has changed from ‘{“t”: <int>, “i”: <int>}’ to ‘{“$timestamp”: {“t”: <int>, “i”: <int>}}’. This new format will be decoded to an instance of Timestamp . The old format will continue to be decoded to a python dict as before. Encoding to the old format is no longer supported as it was never correct and loses type information.

Issues Resolved

See the PyMongo 2.8 release notes in JIRA for the list of resolved issues in this release.

Version 2.7.2 includes fixes for upsert reporting in the bulk API for MongoDB versions previous to 2.6, a regression in how son manipulators are applied in insert() , a few obscure connection pool semaphore leaks, and a few other minor issues. See the list of issues resolved for full details.

Issues Resolved

See the PyMongo 2.7.2 release notes in JIRA for the list of resolved issues in this release.

Version 2.7.1 fixes a number of issues reported since the release of 2.7, most importantly a fix for creating indexes and manipulating users through mongos versions older than 2.4.0.

Issues Resolved

See the PyMongo 2.7.1 release notes in JIRA for the list of resolved issues in this release.

PyMongo 2.7 is a major release with a large number of new features and bug fixes. Highlights include:

• Full support for MongoDB 2.6.

• A new bulk write operations API .

• Support for server side query timeouts using max_time_ms() .

• Support for writing aggregate() output to a collection.

• A new parallel_scan() helper.

• OperationFailure and its subclasses now include a details attribute with complete error details from the server.

• A new GridFS find() method that returns a GridOutCursor .

• Greatly improved support for mod_wsgi when using PyMongo’s C extensions. Read Jesse’s blog post for details.

• Improved C extension support for ARM little endian.

Breaking changes

Version 2.7 drops support for replica sets running MongoDB versions older than 1.6.2.

Issues Resolved

See the PyMongo 2.7 release notes in JIRA for the list of resolved issues in this release.

Version 2.6.3 fixes issues reported since the release of 2.6.2, most importantly a semaphore leak when a connection to the server fails.

Issues Resolved

See the PyMongo 2.6.3 release notes in JIRA for the list of resolved issues in this release.

Version 2.6.2 fixes a TypeError problem when max_pool_size=None is used in Python 3.

Issues Resolved

See the PyMongo 2.6.2 release notes in JIRA for the list of resolved issues in this release.

Version 2.6.1 fixes a reference leak in the insert() method.

Issues Resolved

See the PyMongo 2.6.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.6 includes some frequently requested improvements and adds support for some early MongoDB 2.6 features.

Special thanks go to Justin Patrin for his work on the connection pool in this release.

Important new features:

• The max_pool_size option for MongoClient and MongoReplicaSetClient now actually caps the number of sockets the pool will open concurrently. Once the pool has reached max_pool_size operations will block waiting for a socket to become available. If waitQueueTimeoutMS is set, an operation that blocks waiting for a socket will raise ConnectionFailure after the timeout. By default waitQueueTimeoutMS is not set. See How does connection pooling work in PyMongo? for more information.

• The insert() method automatically splits large batches of documents into multiple insert messages based on max_message_size

• Support for the exhaust cursor flag. See find() for details and caveats.

• Support for the PLAIN and MONGODB-X509 authentication mechanisms. See the authentication docs for more information.

• Support aggregation output as a Cursor . See aggregate() for details.

Warning

SIGNIFICANT BEHAVIOR CHANGE in 2.6. Previously, max_pool_size would limit only the idle sockets the pool would hold onto, not the number of open sockets. The default has also changed, from 10 to 100. If you pass a value for max_pool_size make sure it is large enough for the expected load. (Sockets are only opened when needed, so there is no cost to having a max_pool_size larger than necessary. Err towards a larger value.) If your application accepts the default, continue to do so.

See How does connection pooling work in PyMongo? for more information.

Issues Resolved

See the PyMongo 2.6 release notes in JIRA for the list of resolved issues in this release.

Version 2.5.2 fixes a NULL pointer dereference issue when decoding an invalid DBRef .

Issues Resolved

See the PyMongo 2.5.2 release notes in JIRA for the list of resolved issues in this release.

Version 2.5.1 is a minor release that fixes issues discovered after the release of 2.5. Most importantly, this release addresses some race conditions in replica set monitoring.

Issues Resolved

See the PyMongo 2.5.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.5 includes changes to support new features in MongoDB 2.4.

Important new features:

• Support for GSSAPI (Kerberos) authentication .

• Support for SSL certificate validation with hostname matching.

• Support for delegated and role based authentication.

• New GEOSPHERE (2dsphere) and HASHED index constants.

Note

authenticate() now raises a subclass of PyMongoError if authentication fails due to invalid credentials or configuration issues.

Issues Resolved

See the PyMongo 2.5 release notes in JIRA for the list of resolved issues in this release.

Version 2.4.2 is a minor release that fixes issues discovered after the release of 2.4.1. Most importantly, PyMongo will no longer select a replica set member for read operations that is not in primary or secondary state.

Issues Resolved

See the PyMongo 2.4.2 release notes in JIRA for the list of resolved issues in this release.

Version 2.4.1 is a minor release that fixes issues discovered after the release of 2.4. Most importantly, this release fixes a regression using aggregate() , and possibly other commands, with mongos.

Issues Resolved

See the PyMongo 2.4.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.4 includes a few important new features and a large number of bug fixes.

Important new features:

• New MongoClient and MongoReplicaSetClient classes - these connection classes do acknowledged write operations (previously referred to as ‘safe’ writes) by default. Connection and ReplicaSetConnection are deprecated but still support the old default fire-and-forget behavior.

• A new write concern API implemented as a write_concern attribute on the connection, Database , or Collection classes.

• MongoClient (and Connection ) now support Unix Domain Sockets.

• Cursor can be copied with functions from the copy module.

• The set_profiling_level() method now supports a slow_ms option.

• The replica set monitor task (used by MongoReplicaSetClient and ReplicaSetConnection ) is a daemon thread once again, meaning you won’t have to call close() before exiting the python interactive shell.

Warning

The constructors for MongoClient , MongoReplicaSetClient , Connection , and ReplicaSetConnection now raise ConnectionFailure instead of its subclass AutoReconnect if the server is unavailable. Applications that expect to catch AutoReconnect should now catch ConnectionFailure while creating a new connection.

Issues Resolved

See the PyMongo 2.4 release notes in JIRA for the list of resolved issues in this release.

Version 2.3 adds support for new features and behavior changes in MongoDB 2.2.

Important New Features:

• Support for expanded read preferences including directing reads to tagged servers - See Secondary Reads for more information.

• Support for mongos failover.

• A new aggregate() method to support MongoDB’s new aggregation framework .

• Support for legacy Java and C# byte order when encoding and decoding UUIDs.

• Support for connecting directly to an arbiter.

Warning

Starting with MongoDB 2.2 the getLastError command requires authentication when the server’s authentication features are enabled. Changes to PyMongo were required to support this behavior change. Users of authentication must upgrade to PyMongo 2.3 (or newer) for “safe” write operations to function correctly.

Issues Resolved

See the PyMongo 2.3 release notes in JIRA for the list of resolved issues in this release.

Version 2.2.1 is a minor release that fixes issues discovered after the release of 2.2. Most importantly, this release fixes an incompatibility with mod_wsgi 2.x that could cause connections to leak. Users of mod_wsgi 2.x are strongly encouraged to upgrade from PyMongo 2.2.

Issues Resolved

See the PyMongo 2.2.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.2 adds a few more frequently requested features and fixes a number of bugs.

Special thanks go to Alex Grönholm for his contributions to Python 3 support and maintaining the original pymongo3 port. Christoph Simon, Wouter Bolsterlee, Mike O’Brien, and Chris Tompkinson also contributed to this release.

Important New Features:

• Support for Python 3 - See the Python 3 FAQ for more information.

• Support for Gevent - See Gevent for more information.

• Improved connection pooling. See PYTHON-287 .

Warning

A number of methods and method parameters that were deprecated in PyMongo 1.9 or older versions have been removed in this release. The full list of changes can be found in the following JIRA ticket:

https://jira.mongodb.org/browse/PYTHON-305

BSON module aliases from the pymongo package that were deprecated in PyMongo 1.9 have also been removed in this release. See the following JIRA ticket for details:

https://jira.mongodb.org/browse/PYTHON-304

As a result of this cleanup some minor code changes may be required to use this release.

Issues Resolved

See the PyMongo 2.2 release notes in JIRA for the list of resolved issues in this release.

Version 2.1.1 is a minor release that fixes a few issues discovered after the release of 2.1. You can now use ReplicaSetConnection to run inline map reduce commands on secondaries. See inline_map_reduce() for details.

Special thanks go to Samuel Clay and Ross Lawley for their contributions to this release.

Issues Resolved

See the PyMongo 2.1.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.1 adds a few frequently requested features and includes the usual round of bug fixes and improvements.

Special thanks go to Alexey Borzenkov, Dan Crosta, Kostya Rybnikov, Flavio Percoco Premoli, Jonas Haag, and Jesse Davis for their contributions to this release.

Important New Features:

• ReplicaSetConnection - ReplicaSetConnection can be used to distribute reads to secondaries in a replica set. It supports automatic failover handling and periodically checks the state of the replica set to handle issues like primary stepdown or secondaries being removed for backup operations. Read preferences are defined through ReadPreference .

• PyMongo supports the new BSON binary subtype 4 for UUIDs. The default subtype to use can be set through uuid_subtype The current default remains OLD_UUID_SUBTYPE but will be changed to UUID_SUBTYPE in a future release.

• The getLastError option ‘w’ can be set to a string, allowing for options like “majority” available in newer version of MongoDB.

• Added support for the MongoDB URI options socketTimeoutMS and connectTimeoutMS.

• Added support for the ContinueOnError insert flag.

• Added basic SSL support.

• Added basic support for Jython.

• Secondaries can be used for count() , distinct() , group() , and querying GridFS .

• Added document_class and tz_aware options to MasterSlaveConnection

Issues Resolved

See the PyMongo 2.1 release notes in JIRA for the list of resolved issues in this release.

Version 2.0.1 fixes a regression in GridIn when writing pre-chunked strings. Thanks go to Alexey Borzenkov for reporting the issue and submitting a patch.

Issues Resolved

• PYTHON-271 : Regression in GridFS leads to serious loss of data.

Version 2.0 adds a large number of features and fixes a number of issues.

Special thanks go to James Murty, Abhay Vardhan, David Pisoni, Ryan Smith-Roberts, Andrew Pendleton, Mher Movsisyan, Reed O’Brien, Michael Schurter, Josip Delic and Jonas Haag for their contributions to this release.

Important New Features:

• PyMongo now performs automatic per-socket database authentication. You no longer have to re-authenticate for each new thread or after a replica set failover. Authentication credentials are cached by the driver until the application calls logout() .

• slave_okay can be set independently at the connection, database, collection or query level. Each level will inherit the slave_okay setting from the previous level and each level can override the previous level’s setting.

• safe and getLastError options (e.g. w, wtimeout, etc.) can be set independently at the connection, database, collection or query level. Each level will inherit settings from the previous level and each level can override the previous level’s setting.

• PyMongo now supports the await_data and partial cursor flags. If the await_data flag is set on a tailable cursor the server will block for some extra time waiting for more data to return. The partial flag tells a mongos to return partial data for a query if not all shards are available.

• map_reduce() will accept a dict or instance of SON as the out parameter.

• The URI parser has been moved into its own module and can be used directly by application code.

• AutoReconnect exception now provides information about the error that actually occured instead of a generic failure message.

• A number of new helper methods have been added with options for setting and unsetting cursor flags, re-indexing a collection, fsync and locking a server, and getting the server’s current operations.

API changes:

• If only one host:port pair is specified Connection will make a direct connection to only that host. Please note that slave_okay must be True in order to query from a secondary.

• If more than one host:port pair is specified or the replicaset option is used PyMongo will treat the specified host:port pair(s) as a seed list and connect using replica set behavior.

Warning

The default subtype for Binary has changed from OLD_BINARY_SUBTYPE (2) to BINARY_SUBTYPE (0).

Issues Resolved

See the PyMongo 2.0 release notes in JIRA for the list of resolved issues in this release.

Version 1.11 adds a few new features and fixes a few more bugs.

New Features:

• Basic IPv6 support: pymongo prefers IPv4 but will try IPv6. You can also specify an IPv6 address literal in the host parameter or a MongoDB URI provided it is enclosed in ‘[‘ and ‘]’.

• max_pool_size option: previously pymongo had a hard coded pool size of 10 connections. With this change you can specify a different pool size as a parameter to Connection (max_pool_size=<integer>) or in the MongoDB URI (maxPoolSize=<integer>).

• Find by metadata in GridFS: You can know specify query fields as keyword parameters for get_version() and get_last_version() .

• Per-query slave_okay option: slave_okay=True is now a valid keyword argument for find() and find_one() .

API changes:

• validate_collection() now returns a dict instead of a string. This change was required to deal with an API change on the server. This method also now takes the optional scandata and full parameters. See the documentation for more details.

Warning

The pool_size , auto_start_request , and timeout parameters for Connection have been completely removed in this release. They were deprecated in pymongo-1.4 and have had no effect since then. Please make sure that your code doesn’t currently pass these parameters when creating a Connection instance.

Issues resolved

• PYTHON-241 : Support setting slaveok at the cursor level.

• PYTHON-240 : Queries can sometimes permanently fail after a replica set fail over.

• PYTHON-238 : error after few million requests

• PYTHON-237 : Basic IPv6 support.

• PYTHON-236 : Restore option to specify pool size in Connection.

• PYTHON-212 : pymongo does not recover after stale config

• PYTHON-138 : Find method for GridFS

Version 1.10.1 is primarily a bugfix release. It fixes a regression in version 1.10 that broke pickling of ObjectIds. A number of other bugs have been fixed as well.

There are two behavior changes to be aware of:

• If a read slave raises AutoReconnect MasterSlaveConnection will now retry the query on each slave until it is successful or all slaves have raised AutoReconnect . Any other exception will immediately be raised. The order that the slaves are tried is random. Previously the read would be sent to one randomly chosen slave and AutoReconnect was immediately raised in case of a connection failure.

• A Python long is now always BSON encoded as an int64. Previously the encoding was based only on the value of the field and a long with a value less than 2147483648 or greater than -2147483649 would always be BSON encoded as an int32.

Issues resolved

• PYTHON-234 : Fix setup.py to raise exception if any when building extensions

• PYTHON-233 : Add information to build and test with extensions on windows

• PYTHON-232 : Traceback when hashing a DBRef instance

• PYTHON-231 : Traceback when pickling a DBRef instance

• PYTHON-230 : Pickled ObjectIds are not compatible between pymongo 1.9 and 1.10

• PYTHON-228 : Cannot pickle bson.ObjectId

• PYTHON-227 : Traceback when calling find() on system.js

• PYTHON-216 : MasterSlaveConnection is missing disconnect() method

• PYTHON-186 : When storing integers, type is selected according to value instead of type

• PYTHON-173 : as_class option is not propogated by Cursor.clone

• PYTHON-113 : Redunducy in MasterSlaveConnection

Version 1.10 includes changes to support new features in MongoDB 1.8.x. Highlights include a modified map/reduce API including an inline map/reduce helper method, a new find_and_modify helper, and the ability to query the server for the maximum BSON document size it supports.

• added find_and_modify() .

• added inline_map_reduce() .

• changed map_reduce() .

Warning

MongoDB versions greater than 1.7.4 no longer generate temporary collections for map/reduce results. An output collection name must be provided and the output will replace any existing output collection with the same name. map_reduce() now requires the out parameter.

Issues resolved

• PYTHON-225: ObjectId class definition should use slots.

• PYTHON-223: Documentation fix.

• PYTHON-220: Documentation fix.

• PYTHON-219: KeyError in find_and_modify()

• PYTHON-213: Query server for maximum BSON document size.

• PYTHON-208: Fix Connection repr.

• PYTHON-207: Changes to Map/Reduce API.

• PYTHON-205: Accept slaveOk in the URI to match the URI docs.

• PYTHON-203: When slave_okay=True and we only specify one host don’t autodetect other set members.

• PYTHON-194: Show size when whining about a document being too large.

• PYTHON-184: Raise DuplicateKeyError for duplicate keys in capped collections.

• PYTHON-178: Don’t segfault when trying to encode a recursive data structure.

• PYTHON-177: Don’t segfault when decoding dicts with broken iterators.

• PYTHON-172: Fix a typo.

• PYTHON-170: Add find_and_modify() .

• PYTHON-169: Support deepcopy of DBRef.

• PYTHON-167: Duplicate of PYTHON-166.

• PYTHON-166: Fixes a concurrency issue.

• PYTHON-158: Add code and err string to db assertion messages.

Version 1.9 adds a new package to the PyMongo distribution, bson . bson contains all of the BSON encoding and decoding logic, and the BSON types that were formerly in the pymongo package. The following modules have been renamed:

• pymongo.bson -> bson

• pymongo._cbson -> bson._cbson and pymongo._cmessage

• pymongo.binary -> bson.binary

• pymongo.code -> bson.code

• pymongo.dbref -> bson.dbref

• pymongo.json_util -> bson.json_util

• pymongo.max_key -> bson.max_key

• pymongo.min_key -> bson.min_key

• pymongo.objectid -> bson.objectid

• pymongo.son -> bson.son

• pymongo.timestamp -> bson.timestamp

• pymongo.tz_util -> bson.tz_util

In addition, the following exception classes have been renamed:

• pymongo.errors.InvalidBSON -> bson.errors.InvalidBSON

• pymongo.errors.InvalidStringData -> bson.errors.InvalidStringData

• pymongo.errors.InvalidDocument -> bson.errors.InvalidDocument

• pymongo.errors.InvalidId -> bson.errors.InvalidId

The above exceptions now inherit from bson.errors.BSONError rather than pymongo.errors.PyMongoError .

Note

All of the renamed modules and exceptions above have aliases created with the old names, so these changes should not break existing code. The old names will eventually be deprecated and then removed, so users should begin migrating towards the new names now.

Warning

The change to the exception hierarchy mentioned above is possibly breaking. If your code is catching PyMongoError , then the exceptions raised by bson will not be caught, even though they would have been caught previously. Before upgrading, it is recommended that users check for any cases like this.

• the C extension now shares buffer.c/h with the Ruby driver

• bson no longer raises InvalidName , all occurrences have been replaced with InvalidDocument .

• renamed bson._to_dicts() to decode_all() .

• renamed from_dict() to encode() and to_dict() to decode() .

• added batch_size() .

• allow updating (some) file metadata after a GridIn instance has been closed.

• performance improvements for reading from GridFS.

• special cased slice with the same start and stop to return an empty cursor.

• allow writing unicode to GridFS if an encoding attribute has been specified for the file.

• added gridfs.GridFS.get_version() .

• scope variables for Code can now be specified as keyword arguments.

• added readline() to GridOut .

• make a best effort to transparently auto-reconnect if a Connection has been idle for a while.

• added list() to SystemJS .

• added file_document argument to GridOut() to allow initializing from an existing file document.

• raise TimeoutError even if the getLastError command was run manually and not through “safe” mode.

• added uuid support to json_util .

• fixed a typo in the C extension that could cause safe-mode operations to report a failure ( SystemError ) even when none occurred.

• added a ne() implementation to any class where we define eq() .

Version 1.8 adds support for connecting to replica sets, specifying per-operation values for w and wtimeout , and decoding to timezone-aware datetimes.

• fixed a reference leak in the C extension when decoding a DBRef .

• added support for w , wtimeout , and fsync (and any other options for getLastError ) to “safe mode” operations.

• added nodes property.

• added a maximum pool size of 10 sockets.

• added support for replica sets.

• DEPRECATED from_uri() and paired() , both are supplanted by extended functionality in Connection() .

• added tz aware support for datetimes in ObjectId , Timestamp and json_util methods.

• added drop() helper.

• reuse the socket used for finding the master when a Connection is first created.

• added support for MinKey , MaxKey and Timestamp to json_util .

• added support for decoding datetimes as aware (UTC) - it is highly recommended to enable this by setting the tz_aware parameter to Connection() to True .

• added network_timeout option for individual calls to find() and find_one() .

• added exists() to check if a file exists in GridFS.

• added support for additional keys in DBRef instances.

• added code attribute to OperationFailure exceptions.

• fixed serialization of int and float subclasses in the C extension.

Version 1.7 is a recommended upgrade for all PyMongo users. The full release notes are below, and some more in depth discussion of the highlights is here .

• no longer attempt to build the C extension on big-endian systems.

• added MinKey and MaxKey .

• use unsigned for Timestamp in BSON encoder/decoder.

• support True as "ok" in command responses, in addition to 1.0 - necessary for server versions >= 1.5.X

• BREAKING change to index_information() to add support for querying unique status and other index information.

• added document_class , to specify class for returned documents.

• added as_class argument for find() , and in the BSON decoder.

• added support for creating Timestamp instances using a datetime .

• allow dropTarget argument for rename .

• handle aware datetime instances, by converting to UTC.

• added support for max_scan .

• raise FileExists exception when creating a duplicate GridFS file.

• use y2038 for time handling in the C extension - eliminates 2038 problems when extension is installed.

• added sort parameter to find()

• finalized deprecation of changes from versions <= 1.4

• take any non- dict as an "_id" query for find_one() or remove()

• added ability to pass a dict for fields argument to find() (supports "$slice" and field negation)

• simplified code to find master, since paired setups don’t always have a remote

• fixed bug in C encoder for certain invalid types (like Collection instances).

• don’t transparently map "filename" key to name attribute for GridFS.

The biggest change in version 1.6 is a complete re-implementation of gridfs with a lot of improvements over the old implementation. There are many details and examples of using the new API in this blog post . The old API has been removed in this version, so existing code will need to be modified before upgrading to 1.6.

• fixed issue where connection pool was being shared across Connection instances.

• more improvements to Python code caching in C extension - should improve behavior on mod_wsgi.

• added from_datetime() .

• complete rewrite of gridfs support.

• improvements to the command() API.

• fixed drop_indexes() behavior on non-existent collections.

• disallow empty bulk inserts.

• fixed response handling to ignore unknown response flags in queries.

• handle server versions containing ‘-pre-‘.