[BUG]: RC4 introduces new bug by setting `supportBigNumbers` to `true` with the `mysql2` driver

Author: fr33bitsCreated Jul 1, 2026Updated Sep 17, 2026
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What version of drizzle-orm are you using?

1.0.0-rc.4

What version of drizzle-kit are you using?

1.0.0-rc.4

Other packages

No response

Describe the Bug

[email protected] introduces a bug here in this commit where it adds a line in the mysql2 driver:

typescript
client.config.supportBigNumbers = true;

I've found this to cause an issue because the client property in the object passed to drizzle() does not have a top-level config property:

typescript
const poolConnection = mysql.createPool({
	host: dbConfig.host,
	port: dbConfig.port,
	user: dbConfig.username,
	password: dbConfig.password,
	database: dbConfig.databaseName,
	connectionLimit: dbConfig.connectionPoolLimit,
	enableKeepAlive: true, // default value but set just in case: https://github.com/sidorares/node-mysql2/issues/1898
	ssl: {
		rejectUnauthorized: false
	}
});

...

export const db = drizzle({
	client: poolConnection,
	logger: new DbLogger(),
	relations
});

However setting the client property to poolConnection.pool seems to fix this issue because the top-level pool property does indeed have an object that contains the config property. If this is intended, it should be properly documented, which it is not right now.

Source: drizzle-team/drizzle-orm