mongodb/mongo-c-driver 1.2.0-beta

mongo-c-driver 1.2.0-beta

on GitHub

It is my pleasure to announce to you the first beta release of the MongoDB C driver 1.2.0.

This release is a stable release with additive ABI changes and bugfixes. It is compatible with MongoDB version 2.4 and later.

Version 1.2.0 rewrites mongoc_client_t's internals to match two important new specs for MongoDB drivers: the Server Discovery And Monitoring Spec and the Server Selection Spec. The rewritten client has many advantages:

• All replica set members or mongoses are discovered and periodically
  checked in parallel. The driver's performance is dramatically better and
  more predictable with multi-server deployments, or with a flaky network,
  or when some servers are slow or down.
• Clients from the same mongoc_client_pool_t share a background thread that
  discovers and monitors all servers in parallel.
• Unnecessary round trips for server checks and pings are eliminated.
• Behavior is documented in the specs, and consistent with other drivers, even
  in complex or unusual scenarios.
• The URI's "replicaSet" option is enforced: the driver now refuses to connect
  to a server unless it is a member of a replica set with the right setName.
• Many race conditions related to changing deployment conditions are fixed.

To conform to the new specs, the client now accepts these options in the MongoDB URI; see the mongoc_uri_t documentation for details:

• heartbeatFrequencyMS
• serverSelectionTimeoutMS
• serverSelectionTryOnce
• socketCheckIntervalMS

Other features:

• All timeouts that can be configured in the URI now interpret 0 to mean "use the default value for this timeout".
• The client's read preference can be configured in the URI with the new
  options "readPreference" and "readPreferenceTags", see the mongoc_uri_t
  documentation.
• The new mongoc_uri_get_read_prefs_t function retrieves both the read mode
  and tags from a mongoc_uri_t.
• New accessors mongoc_gridfs_file_get_id, mongoc_client_get_default_database,
  and mongoc_bulk_operation_get_write_concern.
• Debug tracing can be controlled at runtime with mongoc_log_trace_enable and
  mongoc_log_trace_disable.

Notable bugs fixed:

• "wtimeoutms" was ignored for write concerns besides "majority".
• Bulk write operations might fail in mixed-version sharded clusters with
  some pre-2.6 mongos servers.
• Normal operations were logged during startup and could not be silenced.
• A variety of bugs and incorrect results in mongoc_bulk_operation_execute.
• Numerous compiler warnings and build failures on various platforms.
• Copious refinements to the documentation.

Thanks to everyone who contributed to this version of libmongoc.

• A. Jesse Jiryu Davis
• Sujan Dutta
• Jason Carey
• Hannes Magnusson
• Jeremy Mikola
• Derick Rethans
• Samantha Ritter
• Yuchen Xie
• Lloyd Zhou

Peace,

A. Jesse Jiryu Davis