Changelog — PyMongo 2.7.2 documentation

# Changelog

## Changes in Version 2.7.2

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.

## Changes in Version 2.7.1

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.

## Changes in Version 2.7

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.

## Changes in Version 2.6.3

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.

## Changes in Version 2.6.2

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.

## Changes in Version 2.6.1

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.

## Changes in Version 2.6

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.

## Changes in Version 2.5.2

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.

## Changes in Version 2.5.1

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.

## Changes in Version 2.5

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.

## Changes in Version 2.4.2

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.

## Changes in Version 2.4.1

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.

## Changes in Version 2.4

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.

## Changes in Version 2.3

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 - See High Availability and mongos for more information.
- 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.

## Changes in Version 2.2.1

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.

## Changes in Version 2.2

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 Requests for more information.

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.

## Changes in Version 2.1.1

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.

## Changes in Version 2.1

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.

## Changes in Version 2.0.1

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.

## Changes in Version 2.0

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.

## Changes in Version 1.11

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

## Changes in Version 1.10.1

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

## Changes in Version 1.10

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.

## Changes in Version 1.9

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`.

## Changes in Version 1.8.1

- 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__()`.

## Changes in Version 1.8

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.

## Changes in Version 1.7

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.

## Changes in Version 1.6

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.

## Changes in Version 1.5.2

- fixed response handling to ignore unknown response flags in queries.
- handle server versions containing ‘-pre-‘.

## Changes in Version 1.5.1

- added `_id` property for `GridFile` instances.
- fix for making a `Connection` (with slave_okay set) directly to a slave in a replica pair.
- accept kwargs for `create_index()` and `ensure_index()` to support all indexing options.
- add `pymongo.GEO2D` and support for geo indexing.
- improvements to Python code caching in C extension - should improve behavior on mod_wsgi.

## Changes in Version 1.5

- added subtype constants to `binary` module.
- DEPRECATED options argument to `Collection()` and `create_collection()` in favor of kwargs.
- added `has_c()` to check for C extension.
- added `copy_database()`.
- added `alive` to tell when a cursor might have more data to return (useful for tailable cursors).
- added `Timestamp` to better support dealing with internal MongoDB timestamps.
- added name argument for `create_index()` and `ensure_index()`.
- fixed connection pooling w/ fork
- `paired()` takes all kwargs that are allowed for `Connection()`.
- `insert()` returns list for bulk inserts of size one.
- fixed handling of `datetime.datetime` instances in `json_util`.
- added `from_uri()` to support MongoDB connection uri scheme.
- fixed chunk number calculation when unaligned in `gridfs`.
- `command()` takes a string for simple commands.
- added `system_js` helper for dealing with server-side JS.
- don’t wrap queries containing `"$query"` (support manual use of `"$min"`, etc.).
- added `GridFSError` as base class for `gridfs` exceptions.

## Changes in Version 1.4

Perhaps the most important change in version 1.4 is that we have decided to no longer support Python 2.3. The most immediate reason for this is to allow some improvements to connection pooling. This will also allow us to use some new (as in Python 2.4 ;) idioms and will help begin the path towards supporting Python 3.0. If you need to use Python 2.3 you should consider using version 1.3 of this driver, although that will no longer be actively supported.

Other changes:

- move `"_id"` to front only for top-level documents (fixes some corner cases).
- `update()` and `remove()` return the entire response to the lastError command when safe is `True`.
- completed removal of things that were deprecated in version 1.2 or earlier.
- enforce that collection names do not contain the NULL byte.
- fix to allow using UTF-8 collection names with the C extension.
- added `PyMongoError` as base exception class for all `errors`. this changes the exception hierarchy somewhat, and is a BREAKING change if you depend on `ConnectionFailure` being a `IOError` or `InvalidBSON` being a `ValueError`, for example.
- added `DuplicateKeyError` for calls to `insert()` or `update()` with safe set to `True`.
- removed `thread_util`.
- added `add_user()` and `remove_user()` helpers.
- fix for `authenticate()` when using non-UTF-8 names or passwords.
- minor fixes for `MasterSlaveConnection`.
- clean up all cases where `ConnectionFailure` is raised.
- simplification of connection pooling - makes driver ~2x faster for simple benchmarks. see How does connection pooling work in PyMongo? for more information.
- DEPRECATED pool_size, auto_start_request and timeout parameters to `Connection`. DEPRECATED `start_request()`.
- use `socket.sendall()`.
- removed `from_xml()` as it was only being used for some internal testing - also eliminates dependency on `elementtree`.
- implementation of `update()` in C.
- deprecate `_command()` in favor of `command()`.
- send all commands without wrapping as `{"query": ...}`.
- support string as key argument to `group()` (keyf) and run all groups as commands.
- support for equality testing for `Code` instances.
- allow the NULL byte in strings and disallow it in key names or regex patterns

## Changes in Version 1.3

- DEPRECATED running `group()` as `eval()`, also changed default for `group()` to running as a command
- remove `pymongo.cursor.Cursor.__len__()`, which was deprecated in 1.1.1 - needed to do this aggressively due to it’s presence breaking Django template for loops
- DEPRECATED `host()`, `port()`, `connection()`, `name()`, `database()`, `name()` and `full_name()` in favor of `host`, `port`, `connection`, `name`, `database`, `name` and `full_name`, respectively. The deprecation schedule for this change will probably be faster than usual, as it carries some performance implications.
- added `disconnect()`

## Changes in Version 1.2.1

- added Changelog to docs
- added `setup.py doc --test` to run doctests for tutorial, examples
- moved most examples to Sphinx docs (and remove from examples/ directory)
- raise `InvalidId` instead of `TypeError` when passing a 24 character string to `ObjectId` that contains non-hexadecimal characters
- allow `unicode` instances for `ObjectId` init

## Changes in Version 1.2

- spec parameter for `remove()` is now optional to allow for deleting all documents in a `Collection`
- always wrap queries with `{query: ...}` even when no special options - get around some issues with queries on fields named `query`
- enforce 4MB document limit on the client side
- added `map_reduce()` helper - see example
- added `distinct()` method on `Cursor` instances to allow distinct with queries
- fix for `__getitem__()` after `skip()`
- allow any UTF-8 string in `BSON` encoder, not just ASCII subset
- added `generation_time`
- removed support for legacy `ObjectId` format - pretty sure this was never used, and is just confusing
- DEPRECATED `url_encode()` and `url_decode()` in favor of `str()` and `ObjectId()`, respectively
- allow oplog.$main as a valid collection name
- some minor fixes for installation process
- added support for datetime and regex in `json_util`

## Changes in Version 1.1.2

- improvements to `insert()` speed (using C for insert message creation)
- use random number for request_id
- fix some race conditions with `AutoReconnect`

## Changes in Version 1.1.1

- added multi parameter for `update()`
- fix unicode regex patterns with C extension
- added `distinct()`
- added database support for `DBRef`
- added `json_util` with helpers for encoding / decoding special types to JSON
- DEPRECATED `pymongo.cursor.Cursor.__len__()` in favor of `count()` with with_limit_and_skip set to `True` due to performance regression
- switch documentation to Sphinx

## Changes in Version 1.1

- added `__hash__()` for `DBRef` and `ObjectId`
- bulk `insert()` works with any iterable
- fix `ObjectId` generation when using `multiprocessing`
- added `collection`
- added network_timeout parameter for `Connection()`
- DEPRECATED slave_okay parameter for individual queries
- fix for safe mode when multi-threaded
- added safe parameter for `remove()`
- added tailable parameter for `find()`

## Changes in Version 1.0

- fixes for `MasterSlaveConnection`
- added finalize parameter for `group()`
- improvements to `insert()` speed
- improvements to `gridfs` speed
- added `__getitem__()` and `__len__()` for `Cursor` instances

## Changes in Version 0.16

- support for encoding/decoding `uuid.UUID` instances
- fix for `explain()` with limits

## Changes in Version 0.15.2

- documentation changes only

## Changes in Version 0.15.1

- various performance improvements
- API CHANGE no longer need to specify direction for `create_index()` and `ensure_index()` when indexing a single key
- support for encoding `tuple` instances as `list` instances

## Changes in Version 0.15

- fix string representation of `ObjectId` instances
- added timeout parameter for `find()`
- allow scope for reduce function in `group()`

## Changes in Version 0.14.2

- minor bugfixes

## Changes in Version 0.14.1

- `seek()` and `tell()` for (read mode) `GridFile` instances

## Changes in Version 0.14

- support for long in `BSON`
- added `rename()`
- added snapshot parameter for `find()`

## Changes in Version 0.13

- better `MasterSlaveConnection` support
- API CHANGE `insert()` and `save()` both return inserted `_id`
- DEPRECATED passing an index name to `hint()`

## Changes in Version 0.12

- improved `ObjectId` generation
- added `AutoReconnect` exception for when reconnection is possible
- make `gridfs` thread-safe
- fix for `gridfs` with non `ObjectId` `_id`

## Changes in Version 0.11.3

- don’t allow NULL bytes in string encoder
- fixes for Python 2.3

## Changes in Version 0.11.2

- PEP 8
- updates for `group()`
- VS build

## Changes in Version 0.11.1

- fix for connection pooling under Python 2.5

## Changes in Version 0.11

- better build failure detection
- driver support for selecting fields in sub-documents
- disallow insertion of invalid key names
- added timeout parameter for `Connection()`

## Changes in Version 0.10.3

- fix bug with large `limit()`
- better exception when modules get reloaded out from underneath the C extension
- better exception messages when calling a `Collection` or `Database` instance

## Changes in Version 0.10.2

- support subclasses of `dict` in C encoder

## Changes in Version 0.10.1

- alias `Connection` as `pymongo.Connection`
- raise an exception rather than silently overflowing in encoder

## Changes in Version 0.10

- added `ensure_index()`

## Changes in Version 0.9.7

- allow sub-collections of $cmd as valid `Collection` names
- add version as `pymongo.version`
- add `--no_ext` command line option to setup.py