Download the latest Relational Migrator binary from the release page. For installation instructions, see the Installation page.
1.15 Changelog
Released October 17th, 2025
Feature consolidation into AMP:
Some Relational Migrator features are now available via the newly-launched Application Modernization Program (AMP). These features will no longer be accessible directly in the tool and will instead be offered as part of an AMP engagement. These features include:
Continuous sync (CDC) migration mode
LLM-assisted query conversions
Entity code generation for Java, C#, and Javascript
Migration into time series collections
Custom JDBC connections
New Features:
Job update log improvements:
Migration errors are more easily identified by their severity and contain more information, such as the affected row primary key value.
Common error categories now contain clearer and more actionable advice.
Unrecoverable errors now display with a stack trace for easier debugging.
Users can download the entire job update log in JSON Lines (JSONL) format for further analysis.
Relational Migrator now parallelises a migration job across different threads resulting in a substantial performance improvement in most cases. Migration uses all available CPU cores by default. You can specify an integer value for the maximum number of threads to use via the
migrator.connector.sink.common.max.threads
property.You can toggle this behavior off by setting the
migrator.connector.sink.common.multithreaded
property tofalse
in theuser.properties
file.A Linux tarball (.tar.gz) package is available and is now the recommended way to install Relational Migrator on most Linux distributions.
Bug Fixes:
Default values (as defined in the source database) are now completely ignored and the actual value stored in the row is used regardless of whether it exists.
Field names that conflict with the parent mapping are now disallowed when merging to a parent mapping. Parent mapping field names cannot override child field names using the dot notation.
Generated JSON schemas now include the required property list and also correctly include null types in addition to the main types where applicable.
1.14.1 Changelog
Released August 20, 2025
Improvements:
Added
collectionFilters
property to thePOST
/jobs
endpoint to include or exclude collections for a migration.New API endpoint to get all collections for a project under
api/v1/project/{projectId}/collections
.Users can now set the
migrator.engine.transform.calculated.field.timeout
property to configure the timeout value (in seconds) for calculated field generation.
Bug Fixes:
Fixed issue where a nested embedded array may be missing when using wrapped key strategy and
Merge Fields into the Parent
option on parent document.Fixed verification issue where all fields having the same path in an embedded array could result in a false positive.
Fixed performance issue on the
Select tables
screen and theJob update log
when a large amount of rows are shown.Fixed an issue where a very slow startup time could cause a snapshot migration to terminate early, having processed zero rows.
1.14 Changelog
Released July 14, 2025
Important
CDC Update & Data Integrity Issues Resolved:
Relational Migrator version 1.14 is a required upgrade for all users. Relational Migrator version 1.14 resolves data integrity issues that could cause silent data loss or corruption in Continuous (CDC) migration configuration and re-enables CDC mode for all projects. Previously migrated data from versions 1.13.2 and earlier may be affected if it meets the criteria specified below.
MongoDB recommends that customers review previously-migrated production and test data for correctness. For concerns or assistance, open a MongoDB support ticket.
Critical Bug Fixes:
Fixed an issue for mappings with an embedded document that contains an embedded array and has the
Merge Fields into the Parent
option enabled. This created duplicate embedded array elements in the incorrect location.Fixed an issue where mappings containing a cyclic dependency loop with an embedded array could have the primitive array replaced with an array of objects.
Critical Bug Fixes for Continuous (CDC) Migrations:
The following fixes resolve data integrity issues affecting CDC migrations:
Fixed a CDC issue where multiple row change events in a single batch can cause children to not be updated due to a malformed $match clause.
Fixed a CDC issue where previous embedded array entries are not removed if the parent is updated such that it now matches zero array children.
Fixed a CDC issue with row change events during Continuous migration may insert multiple additional array entries within deeply nested array mappings.
Fixed a CDC issue affecting mappings using
Calculated ID
fields containing columns other than primary key(s), where change events can result in missing child objects or incorrect subsequent updates.Fixed a CDC issue for when null handling strategy
omit
is used, updates which set a field value to null are not applied.Fixed a CDC issue where embedded mapping children are not refreshed after update to join fields in table with no primary key.
Fixed a CDC issue caused by a CDC row change event resulting in additional array entries if a table with no primary key is used for embedded array mapping with excluded fields.
Fixed a CDC issue caused by a CDC row change event that may apply child updates to nested embeddings out of order.
Fixed an issue where mappings with an embedded array could have the primitive array replaced with an array of objects.
Improvements:
All indexes created in target collections during migration are now retained by default.
Removed superfluous logging.
Bug Fixes:
Fixed a CDC issue for mappings containing
Document > Array > Document
where an object ID containing a dot.
character caused a fatal error.
1.13.2 Changelog
Released May 27, 2025
Data Integrity Issues Update:
Investigation and resolution of data integrity issues affecting certain CDC and snapshot migration configurations is ongoing as a high-priority project. Continuous mode migrations (CDC) remains disabled in this release for projects that contain embedded documents and arrays. Snapshot migrations and 'one-to-one' CDC migrations that contain no embeddings are still enabled.
Bug Fixes:
Fixed an issue where snapshot migrations containing circular references (where the set of tables cannot be ordered such that each parent is fully migrated before any embedded documents or arrays) may result in one or more embeddings being omitted.
Migration job warnings no longer count towards the error limit for that job.
1.13.1 Changelog
Released April 29, 2025
Data Integrity Advisory:
Warning
This release includes two critical fixes for data integrity issues affecting previous versions of Relational Migrator. The Relational Migrator team has also identified further data integrity issues that affect certain Snapshot and Continuous Migration configurations. These issues are scheduled to be addressed in an upcoming release. This 1.13.1 release temporarily disables Continuous Migrations (CDC mode) for projects which include any embedded document or array mappings. If Relational Migrator indicates that you may be affected when running a new CDC job after upgrading, MongoDB recommends holding off on performing Continuous Migration jobs in production or manually verifying your migrated data for potential data loss until further updates are available.
Critical Bug Fixes:
Fixed an issue where Snapshot Migrations could fail to populate deeply nested Embedded Arrays if the mappings are structured such that an Embedded Document mapping is between two Embedded Array mappings in the mapping hierarchy.
Fixed an issue with Continuous Migrations where relational tables with no primary key could cause duplicate entries in embedded arrays when the row is updated.
Improvements:
Improved performance for snapshot migrations containing embedded arrays.
Faster initial database loads when connecting to large databases containing many tables.
Enhanced migration and verification errors with more details and debugging information.
Improved error and warning reporting for pre-migration and post-migration tasks.
Imported and new projects now use a consistent naming scheme to generate their project ID.
Added support for Oracle JDBC Driver version 23.
Bug Fixes:
Fixed an issue with idempotent-mode snapshot migrations where subsequent runs of the migration could cause duplicate entries in embedded arrays. This occurs with nested mappings where the embedded array contains additional embedded documents or arrays.
Fixed an issue where fields containing dot characters in their name cause errors during snapshot and continuous migrations.
Fixed issues where editing an embedded mapping field to add the prefix
_id
results in the unexpected UI behaviour.Updated generated prerequisite configuration and permissions SQL script for Oracle to include AWS RDS instructions.
1.13.0 Changelog
Released March 24, 2025
New features:
Pre-Migration Analysis is now in Public Preview. This feature allows you to identify migration issues before starting and get actionable recommendations for a smooth migration. Pre Migration Analysis supports the following databases:
Oracle
SQL Server
PostgreSQL
MySQL
Bug fixes:
Fixed an issue where job API calls would hang when table filters returned an empty result.
Fixed an issue that prevented users from saving calculated key fields for projects that use the single-inherited or wrapped key handling options.
Fixed an issue with embedded array mappings and excluded fields, where blank source data could trigger an 'unset' error rather than being processed silently.
1.12.0 Changelog
Released February 3, 2025
New features:
Added support for four source databases, using JDBC connectivity to enable snapshot-based data migration and database object conversion from:
YugabyteDB
CockroachDB
SAP Sybase IQ (SAP IQ)
SAP SQL Anywhere
Note
JDBC connection support for these databases is currently in Public Preview. Users can also add custom relational database support by creating a custom JDBC connector.
Added support for X.509 certificate authentication for client authentication on MongoDB target databases.
Added information for MongoDB Atlas users attempting large data migrations to lower-tier MongoDB Atlas clusters which may result in extended migration time. For large jobs where migration performance is a consideration, users may be able to reduce total migration time by up to 54% by upgrading to a faster Atlas tier.
Added optional news section to inform users of new migrator tool capabilities, important upgrades and security announcements. This online-only feature can be disabled in user properties.
Improved error reporting when skipping import of unsupported binary data types in Microsoft SQL Server (FILESTREAM type) and Oracle (LONG, LONG RAW and BFILE types).
Increased the maximum file size of supported DDL schemas file from 4MB to 20MB.
Bug Fixes:
Fixed an issue where Postgres created a duplicate replication slot in certain scenarios.
1.11.0 Changelog
Released November 25, 2024
New features:
New database connection management feature makes it easier to save and manage a large number of database connections, and switch between database environments such as QA, dev or production.
Improved query conversion by adding the option to use strongly-typed Java entities in the signatures of converted queries.
Added support for converting Oracle packages and SQL Server functions in query converter.
Added support for the latest Postgres 17 and MySQL 8.4/9.0 database versions.
Improved support for connecting to Oracle pluggable databases (PDBs).
Added support to "Bring Your Own LLM" using a customer-managed LLM service for AI code generation instead of the default MongoDB-hosted service.
Temporarily disabled the ability to select Atlas clusters from a list when signed in with an Atlas account
Bug Fixes:
Fixed an issue where a "No foreign key found" error could occur in some cases with multiple foreign key embeddings.
1.10.0 Changelog
Released October 2, 2024
New features:
New bulk conversion UI and API for Query Converter to automatically convert large numbers of SQL queries, views, and stored procedures.
Snapshot jobs now create top-level documents using a non-idempotent bulk insert method. This improves performance.
Added explicit control over idempotent behavior through the
migrator.engine.transform.idempotency: true
setting in theuser.properties
file.Internal indexes used for migration are automatically deleted after job completion. This improves performance.
Updated SQL Server JDBC driver to the latest version.
Added Basic Authentication support for Kafka.
Added more detailed logging in the application's log file in the event of migration errors.
Simplified the structure of Java POJO classes in Code Generation.
Bug fixes:
Fixed an issue where tables were deselected for import into a project after filtering the table list.
Fixed a UI issue with the Migration Job Log which prevented it from being resized when it contained a large number of entries.
Fixed an issue where remote API calls such as query conversions were not routed through the system proxy.
Fixed an issue where individual rows exceeding the 16MB document limit caused the job to stop immediately, instead of continuing up to the error threshold.
Fixed an issue where data verification was unable to detect some issues caused by precision differences between source and target data types.
Fixed an issue where each query could be imported twice.
Fixed an issue where converted queries sometimes used incorrect paths for embedded mappings.
1.9.0 Changelog
Released August 20, 2024
New features:
Query Converter now allows you to test your relational and converted queries and compare the results in the Test Queries pane.
DB2 LUW database support is now in Public Preview. Users interested in DB2 LUW and mainframe (DB2 for i) support, please contact your MongoDB account representative for full details or a guided evaluation.
SQL Server connections now default to
trust server certificate
. This setting can be unchecked in the SSL tab.
Fixes:
Fixed an issue where connectors failed to upload when starting migration jobs using Confluent Cloud.
Fixed an issue where migration jobs failed to start for Postgres databases when the credentials were supplied with query string parameters.
Fixed an issue where multiple synthetic foreign keys between the same tables were not treated as a composite key.
Fixed an issue where the migration job dialog indicated that the database was not ready if the preflight test failed to run.
Fixed an issue where query files were not deleted when projects were deleted.
Fixed an issue where queries could not be imported from a Postgres database when connected as a user who is not the owner.
1.8.0 Changelog
Released July 09, 2024
New features:
New conditional mapping rules for more advanced transformations:
Mapping rule filters to include or exclude documents based on a custom Javascript expression.
Array conditions to sort and limit embedded arrays, supporting the application of the subset pattern.
Improved modeling of foreign keys to support tables with multiple, potentially ambiguous references to a foreign table.
New light mode in web UI.
New undo/redo functionality for mapping rule editing.
Improved stored procedure conversion for Postgres and MySQL database by adding procedure headers.
1.7.0 Changelog
Released May 20, 2024
New features:
More detailed statistics while running a migration job, including viewing percentage complete, estimated time to completion, and which table is currently being processed.
Users can now recover a continuous migration job if the Relational Migrator application is restarted while a migration job is running.
New Job Management REST API. The REST API allows users to start, stop and monitor migration jobs programmatically.
Bug Fixes:
Fixed an issue where Atlas Sign In sessions expired after Relational Migrator was idle for a short amount of time.
Fixed an issue where it was not possible to import queries from Oracle databases where the schema or database name contained dots.
Fixed an issue where generated Java POJO classes used incorrect types for date-typed fields.
Fixed an issue where verification could be aborted for schemas with composite keys when some key fields are excluded.
Fixed an issue where jobs stall without progress if no tables for the schema were found in the source database.
1.6.0 Changelog
Released April 18, 2024
New features:
Users can migrate time series data into MongoDB with native Time Series support.
Users can migrate data from TimescaleDB Hypertables.
Users can migrate from a database that has a name different from the name used when creating the corresponding project.
Migration performance improves by setting write concern to 1 by default (can be overridden in MongoDB URI).
More detailed job logging.
Bug fixes:
It is now possible to create projects and run migration jobs when the database name or schema name contains dot characters.
Fixed an issue where it was not possible to create a calculated field with the same name as an excluded regular field.
Miscellaneous quality improvements to the query converter.
1.5.0 Changelog
Released March 6, 2024
New features:
Query converter is now in public preview.
Query converter now requires you to sign into a MongoDB Atlas account. When you sign into Atlas, the process for selecting Atlas clusters in a migration job is dynamically populated.
Query converter now supports conversion of relational database DML triggers to MongoDB Atlas Triggers.
Improvements:
Query converter now allows you to convert SQL queries and views to C#, Java, or JavaScript.
Bug fixes:
Minor improvements to job recoverability and metrics.
1.4.6 Changelog
Released February 12, 2024
Improvements:
Added support for Oracle 11g as a source database.
New status indicator on the project page that shows if a migration is running.
Improved permissions checks against MongoDB database when starting a new migration.
Improvements to Query Converter (private preview).
Bug fixes:
Fixed an issue where completed migrations could not mark themselves as complete in web interface.
1.4.4 Changelog
Released January 29, 2024
Improvements:
Improved synthetic foreign keys to be preserved after schema refresh.
Fix for fully-offline deployments in air gapped environments.
Fix for certain combinations of mappings, specifically two different mappings at the same level of embedding.
Various minor fixes and improvements to Sybase database support, CDC stage metrics, verification stage, database exports, and logging.
1.4.3 Changelog
Released December 11, 2023
New features:
Sybase ASE database support is now available for one-time snapshot migration jobs and stored procedure conversion.
Confluent-hosted Kafka support for participants in the Kafka early access program. This release adds prebuilt support for connecting to a Kafka cluster managed by the Confluent hosting provider.
Note
Kafka is an open-source platform for distributed, high-availability workloads. To gain access to Relational Migrator with Kafka support, contact your MongoDB account team to sign up for the Kafka Early Access Program.
Integration supported with Hackolade.
Hackolade is a visual data modeling tool. You can explore schemas in Hackolade by importing a Relational Migrator .relmig file. For details, see the Hackolade help article.
Improvements:
Improved SQL query conversion quality for the Query Converter (private preview).
Improved application performance through expanded use of available memory in suitable server environments.
1.3.3 Changelog
Released November 7, 2023
Improvements:
Performance improvements for migration jobs that create large arrays.
Fixed an issue where schema discovery failed on schema names that contain the dash character.
1.3.2 Changelog
Released October 25, 2023
Improvements:
Improved performance when Relational Migrator analyzes large relational schemas.
Relational Migrator now integrates with the Windows certificate store for SSL connections.
New features:
New installer and binaries for Mac M1 architectures.
Mapping rules now show the original column and type used to generate an
_id
field.Improved error messages in query converter (private preview).
1.3.1 Changelog
Released October 10, 2023
New features:
Ability to select
C#
,Java
, andJavaScript
target languages for stored procedure conversions in the query converter (private preview).Query conversions are now included when you export/import projects.
Bug fixes:
Fixed an issue where update events could return errors in CDC jobs.
Fixed an issue where Relational Migrator could hang while trying to detect if a new version was available.
Fixed an issue where all tables could be unexpectedly unchecked when selecting tables for a project.
Improvements to execution of migration jobs under the Kafka deployment model (private preview).
1.3.0 Changelog
Released September 26, 2023
New features:
The Query Converter feature is now in private preview.
Bug fixes:
SQL Server connections now require a database name, which resolves some issues caused by inferring the database name.
Improvements to the Mac and Windows installers.
1.2.0 Changelog
Released September 4, 2023
New features:
Ability to change the data type for migrated fields.
Ability to control how null values are represented in the migrated data.
Ability to use calculated fields for a collection's
_id
value.Diagnostic dump includes configuration files to help streamline support.
Bug fixes:
Improves to validation and error handling in mapping rules.
Improves ability to parse a wider range of Oracle DDL files.
Fixes an issue where tables were lost when refreshing a schema using SQL Server and Windows authentication.
Fixes an issue where CDC updates may target the wrong document when tables do not have a primary key.
Fixes an issue where database passwords can be incorrectly saved to the browser's password library.
1.1.3 Changelog
Released July 26, 2023
New features:
Support for connecting to a SQL Server named instance.
Collection names now show for JSON schema files created from the Code Generation screen.
Bug fixes:
Fixes a post-migration job issue where data verification sometimes stops or displays as not started.
Fixes an issue where JSON columns containing top-level arrays cannot be migrated.
Fixes an issue where excluded fields can overwrite calculated fields with the same name.
Fixes an issue where calculated fields based on decimal column values return
NaN
.Fixes an issue where some diagram view fields are cut off after you change the project level key handling option.
1.1.2 Changelog
Released Jun 22, 2023
Relational Migrator 1.1.2 is now generally available. Relational Migrator assists in migrating your relational workloads to MongoDB.