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go-mssqldb connection options

This article provides a complete reference for all connection parameters accepted by the go-mssqldb driver. For connection string format syntax, see Connection strings.

Common parameters

Parameter Aliases Default Description
user id user - SQL Server login name.
password - - Password for the SQL Server login.
database - - Target database.
connection timeout - 0 Login timeout in seconds. 0 waits indefinitely. Prefer Go contexts for connection and query timeouts.
dial timeout - 15 x protocol count Network dial timeout in seconds. 0 waits indefinitely. The driver defaults to 15 seconds per registered protocol.
encrypt - false Encryption mode. Azure SQL always requires encryption server-side. See Encryption and certificates.
app name - - Application name sent in the login record.
authenticator - - Custom authenticator registered by external packages such as azuread.

Server and port

In ADO and ODBC formats, the server and port are separate parameters:

Parameter Default Description
server localhost SQL Server host name, optionally including \instance.
port 1433 TCP port number.

In URL format, specify the host and port directly in the URL: sqlserver://host:port.

Failover

Parameter Default Description
failoverpartner - Failover partner server host name.
failoverpartnerspn - Service Principal Name (SPN) for the failover partner.
failoverport 1433 TCP port for the failover partner.

When the primary server is unreachable, the driver attempts to connect to the failover partner automatically.

Network and performance

Parameter Default Description
packet size 4096 TDS packet size in bytes. Valid range: 512-32767.
keepAlive 30 Keep-alive interval in seconds. 0 uses the OS default.
TrustServerCertificate Depends on encrypt When true, skip server certificate validation. The default is false when encrypt is specified and true when encrypt is omitted. Ignored when encrypt=strict. Not recommended for production.
multisubnetfailover - Enable multi-subnet failover for AlwaysOn Availability Groups.

Application intent

Parameter Values Description
ApplicationIntent ReadOnly, ReadWrite Declares whether the application connects for read-only or read-write operations. Used with AlwaysOn read-only routing.

Workstation and SPN

Parameter Default Description
Workstation ID - Workstation name sent in the login record.
ServerSPN - Service Principal Name for the SQL Server. Required only in non-default SPN configurations.

Protocol

Parameter Values Description
protocol tcp, np, lpc, admin Transport protocol. See Protocols.
pipe - Named pipe path. Only applies when protocol=np.

Always Encrypted

Parameter Default Description
columnencryption None Set to true to enable Always Encrypted. See Always Encrypted.

Encryption and TLS

Parameter Default Description
encrypt See Common parameters strict (TDS 8.0), true/mandatory, false/optional, disable.
TrustServerCertificate Depends on encrypt Skip certificate validation when true. The default is false when encrypt is specified and true when encrypt is omitted. Ignored when encrypt=strict.
certificate None Path to a PEM or DER certificate file for certificate chain validation.
serverCertificate None Path to a PEM or DER certificate file for byte-level comparison (v1.5.0 and later).
hostnameincertificate None Override the host name used during TLS certificate validation.
tlsmin None Minimum TLS version: 1.0, 1.1, 1.2, 1.3.

For detailed encryption guidance, see Encryption and certificates.

Log flags

Use the log parameter to control diagnostic output. Values are bitmask flags, and you can combine them by adding the integer values:

Value Description
1 Log errors
2 Log messages
4 Log rows
8 Log SQL statements
16 Log parameters
32 Log transactions
64 Log debug information
128 Log retries

Example: to log errors and SQL statements, set log=9 (1 + 8).

For more information, see Logging and diagnostics.

uniqueidentifier columns

The driver reads uniqueidentifier columns as raw byte arrays by default. To get a standard GUID-formatted string, scan into mssql.UniqueIdentifier instead of string or []byte. The driver doesn't support automatic GUID conversion through connection parameters.

SessionInitSQL

SessionInitSQL isn't a connection string parameter. Set it through the NewConnectorConfig API:

import (
    "database/sql"
    "github.com/microsoft/go-mssqldb"
    "github.com/microsoft/go-mssqldb/msdsn"
)

config := msdsn.Config{
    Host:     "<server>",
    Port:     1433,
    Database: "AdventureWorks2025",
}

connector := mssql.NewConnectorConfig(config)
connector.SessionInitSQL = "SET ANSI_NULLS ON"
db := sql.OpenDB(connector)

The SQL statement runs immediately after each new connection is established, before the connection is returned to the caller.

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