MSSQL

Spin up an isolated Microsoft SQL Server branch of your remote database with mirrord

This page covers DB branching for Microsoft SQL Server (MSSQL). For the general concepts, the full list of config fields, and how a session behaves, see the DB Branching overview.

MSSQL branching requires operator 3.150.0, mirrord CLI 3.195.0, and operator Helm chart 1.57.0 with the operator.mssqlBranching value set to true.

Basic Configuration

{
  "feature": {
    "db_branches": [
      {
        "id": "users-mssql-db",
        "type": "mssql",
        "version": "2022-latest",
        "name": "users-database-name",
        "connection": {
          "url": "DATABASE_URL"
        },
        "copy": {
          "mode": "empty"
        }
      }
    ]
  }
}

The connection field describes how mirrord locates the source database connection details - a full connection URL or individual parameters (host, port, user, password, database). See Connection Modes for all supported sources, including Kubernetes Secrets, Google Secret Manager, literal values, and composite environment variables.

Copy Modes

The copy field controls what data gets cloned when creating an MSSQL branch.

Mode	What gets cloned	Best for
"empty" (default)	Nothing - an empty database with no schema or data	Workflows where your application initializes the schema or runs migrations as part of startup
"schema"	Only the table structures (schemas) from the source database, without any data	Testing schema changes or local development where structure is needed but data is not
"all"	Everything from the source database - both schema and data	A full clone of your environment data for debugging or reproducing production-like scenarios

Use "mode": "all" with caution. It’s only recommended for very small or empty databases. Copying large datasets can significantly increase branch creation time and storage usage.

Filtered Data Clone

Developers can customize what gets copied per table. This allows copying only specific rows or subsets of data using SQL query filters.

{
  "copy": {
    "mode": "schema",                   // Or "empty" as explained below
    "tables": {
      "users": {
        "filter": "name = 'alice' OR name = 'bob'"
      },
      "orders": {
        "filter": "created_at > 1759948761"
      }
    }
  }
}

In this example

The schema for all tables is cloned. The users table copy includes only rows for alice and bob. The orders table copy includes only rows created after a certain timestamp.

Filtering can also be combined with "mode": "empty", in which case only the specified tables (and their filtered data) are copied, while all others are excluded.

Note: Filtering is not compatible with "mode": "all". If both are specified, mirrord ignores the tables configuration.

The dump_args field is not supported for MSSQL. MSSQL branches use their own internal dump mechanism, so only MySQL and PostgreSQL branches accept custom dump arguments.