Release Notes for MongoDB Connector for BI

MongoDB Connector for BI 2.8.2

Released Nov 16, 2018

  • Fixes correctness bugs discovered in polymorphic schema mapping, query cancellation, and IN queries.
  • Fixes a performance regression in a common query pattern.

MongoDB Connector for BI 2.8.1

Released Nov 09, 2018

  • Fixes a bug in the behavior of the max_execution_time system variable.

MongoDB Connector for BI 2.8.0

Released Nov 06, 2018

Features and Performance Improvements

  • Improvements to the BI Connector’s type system and the way it handles polymorphic data.
  • Users can alter the type of a given column.
  • Users can access “dirty” datasets without query errors.
  • Support for pushdown of the GROUP_CONCAT aggregation function.
  • Non-admin users can set global variables.

Bug Fixes

  • Improvements in parsing strToDateTime to float.
  • Fixes to how the BI Connector honors readPreference specifications.

MongoDB Connector for BI 2.7.0

Released Oct 02, 2018

Features and Performance Improvements

  • Collapse associative functions
  • Support the optimize_view_sampling global variable
  • Support the polymorphic_type_conversion_mode session/global variable
  • Improve filter optimization for MongoDB versions 3.6 and later
  • Expose type_conversion_mode in configuration parameters
  • Cache catalog columns for quicker lookup

Bug Fixes

  • Fix incorrect semantics for null safe equality operator ( <=> )
  • The || operator returns incorrect type (and value) when operating on two strings
  • Add DRDL type validation
  • Support CAST to unsigned
  • Fix WHERE clause removed in certain cross-join queries
  • Fix some incorrect left self-join results when dynamic schemas are used
  • Support turning off view optimization with $match
  • ODBC driver on macOS should install in versioned directories
  • Fix ODBC driver installer issue on macOS that caused unicode driver to be reported as ANSI

Released version 1.2.0 of the MongoDB ODBC Driver.

MongoDB Connector for BI 2.6.1

Released Sep 21, 2018

  • Resolved an issue caused by how scalar functions handle string values.

We encourage Tableau users running BIC 2.6.0 to upgrade to 2.6.1.

MongoDB Connector for BI 2.6.0

Released Sep 04, 2018


Users can use EXPLAIN to return details of aggregation pipeline used to generate query results.

Common Table Expression Support

The BI Connector now supports queries that include Common Table Expressions.

MongoDB Connector for BI 2.5.0

Released May 23, 2018

  • Improved memory management for mongosqld.
  • New SSPI support for mongosqld on Windows.
  • The --sampleNamespaces option now supports exclusion.
  • NULL valued types are now cast to varchar during sampling.
  • Optimized COUNT(*) query performance.
  • SIN, COS, TAN are now pushed down.

New SSPI Support

Windows Clients may now use kerberos to authenticate against the BI Connector.

NULL Valued Types Are Now Cast to Varchar During Sampling

This resolves the issue where queries would fail due to NULL values being ignored during sampling. Now, NULL values will be cast as SQL type VARCHAR.

SIN, COS, TAN Are Now Pushed Down

BI Connector will now push down SIN, COS, and TAN SQL functions. This will improve performance for queries using these functions.

MongoDB Connector for BI 2.4.1

Released Mar 09, 2018

We’ve released version 2.4.1 of the MongoDB Connector for BI for production deployment. This release contains minor bug fixes for users of the BI Connector and is a recommended upgrade for all 2.4 users.

MongoDB Connector for BI 2.4.0

Released Feb 21, 2018

MongoDB Connector for BI version 2.4 improves more expressive queries. New features include:

Aggregate Expressions

BI Connector 2.4 improves support for aggregate expressions including math, date, and string functions.

Improved Support for Subqueries and Non-equijoins

With version 2.4, mongosqld has improved support for subqueries and non-equijoins.

MongoDB Connector for BI 2.3.1

Released Nov 10, 2017

  • Fixes minor incompatibility with MongoDB 3.2.

MongoDB Connector for BI 2.3.0

Released Nov 08, 2017

  • Simplified and centralized Schema Management.
  • Supports log rotation.
  • Standardized logging in the BI Connector.
  • Push LTRIM, RTRIM and TRIM functions down to MongoDB.

MongoDB Connector for BI version 2.3 improves enterprise deployment support. The new features include:

Improved Schema Management

In BI Connector 2.3, mongosqld includes the schema mapping functionality previously found in mongodrdl.

Log Rotation

With version 2.3, you can rotate the mongosqld logs. To rotate the logs, issue a command or restart mongosqld.

MongoDB Connector for BI 2.2.1

Released Aug 29, 2017

  • Fixes lack of support for Read Preference tags which are used when targeting reads to specific members of a replica set.

MongoDB Connector for BI 2.2.0

Released Jul 31, 2017

  • Supports authenticating directly against MongoDB using the new C and JDBC authentication plugins. These plugins support SCRAM-SHA-1 and PLAIN mechanisms and remove the SSL requirement for authentication. The authentication plugins can be found on GitHub:

  • Supports configuration files for mongosqld.

  • Supports installing and running mongosqld as a Windows system service.

  • Provides a Windows MSI installer for the MongoDB Connector for BI.

  • Provides new command line arguments for default auth mechanism and database:

    • Authentication Options:


      default user source (default of admin)

      --defaultAuthMechanism arg

      default authentication mechanism (default of SCRAM-SHA-1)

  • Provides a new startup option to specify default VARCHAR length

  • Provides mongosqld status metrics with SHOW STATUS

    • Reports the following metrics reported:
      • Connections
      • Queries
      • BytesSent
      • Threads Connected
  • Can bind mongosqld to multiple IP addresses

  • Provides a new runtime options to limit memory usage of GROUP, SORT, and JOIN stages

Authentication Plugins

MongoDB Connector for BI Version 2.0 introduced passthrough authentication, in which clients authenticate as a user defined in MongoDB, without the need to create a separate user within the connector itself.

MongoDB Connector for BI Version 2.2 further increases ease of use with a set of authentication plugins which can authenticate users through the connector without the need for SSL certificates. These plugins perform user authentication via the SASL framework and support the SCRAM-SHA-1 and PLAIN authentication mechanisms. We currently provide authentication plugins in the following languages:

  • Java - for use with MySQL’s Connector/J driver
  • C - for use with the MySQL ODBC driver and the MySQL Shell

MongoDB Connector for BI 2.1.0

  • Provides substantial performance improvements for some common JOIN scenarios.
  • Pushes $match stages earlier in the aggregation pipeline to improve to index utilization.
  • Pushes down more SQL functions and operators to the aggregation pipeline.
  • Supports additional SQL language features, such as USE and SHOW CREATE TABLE statements, STRAIGHT_JOIN, the unary plus (+) operator, and the INTERVAL keyword in date arithmetic.


mongosqld no longer offers the --fork option.

To run mongosqld in the background, use the nohup command:

nohup mongosqld [options] &

MongoDB Connector for BI 2.0.0

Released Nov 29, 2016

Improved Server-Side Execution

The MongoDB Connector for BI delivers significant performance and scalability improvements by moving as much execution as possible to the underlying MongoDB instance. Pushing execution down to the server reduces network latency and reduces bandwidth consumption.

This approach also reduces memory and CPU consumption in the MongoDB Connector for BI itself.

Pass-through Authentication

The user authentication process is now passed through the MongoDB Connector for BI to the underlying MongoDB instance. Users now authenticate as a user already created within MongoDB.

Simplified Architecture

The MongoDB Connector for BI package is now trimmed down from four separate components to two:

This tool connects to a MongoDB instance and generates a Document-Relational Definition Language (DRDL) file, which maps a given collection shape to relational schema.

Once installed and run as a daemon, mongosqld responds to SQL queries, requests for DB information, and schema from the requesting BI tool via the MySQL wire protocol.

mongosqld requires at least one DRDL file to start. You will need to have defined your schema with mongodrdl before starting mongosqld.

SQL Compatibility

MongoDB Connector for BI Version 2.x is compatible with SQL-99 SELECT statements, and uses the MySQL wire protocol.

MongoDB Connector for BI 2.0.2

Released Jan 5, 2017

  • Hides .pem key file passwords in logs.
  • mongodrdl ignores binary fields when generating DRDL files.
  • Supports queries that SELECT variables prefixed with “mongodb”.
  • Fixes incorrect result set from a CROSS JOIN.
  • Supports leading “.” characters on table names.

MongoDB Connector for BI 2.0.1

Released Dec 13, 2016

  • Fixes precedence issue with the NOT operator.
  • Fixes error looking up privilege information in databases with capital letters.
  • Supports LIKE pattern matching in SHOW COLUMNS queries.
  • Improves formatting of aggregation pipeline in logs.
  • Fixes substring function when the combined length of the starting index and substring exceeds the length of the string.