Cloning a Hosted Database

How it works

In some cases you might want to clone your database from Hosted so that you can access Dolt's command line interface. While much of the command line is available in SQL there are some CLI-specific features that can be helpful for debugging your database offline.

In order to clone from Hosted, we needed to add support for exposing the databases on a Hosted sql-server as a read-only remotesapi endpoint. When you run sql-server with this configuration, it will:

1. Listen on an indicated port and serve read-only remotesapi traffic on that port

2. Use any server-side TLS associated with the sql-server itself as part of that listener

3. Use the deployment's user and password in the sql-server config as password authentication credentials for accessing the exposed data

Once you allow the remotesapi to be exposed for your Hosted deployment (available only for deployments with Web PKI certificates), you can simply set a DOLT_REMOTE_PASSWORD environment variable and provide a username to the dolt clone command. You'll see these instructions in the Connectivity tab of your deployment page.

Example

When you're using Hosted as your production database, there might be some performance-heavy operations or tests you want to run in isolation so you don't impact production, such as beta testing a considerable schema migration or running a big analytics query. Clone makes it easy to get a local copy of your Hosted database with one command. Do whatever potentially destructive or performance-degrading operations on your laptop while respecting your production database.

1. Expose remotesapi endpoint

In order to enable cloning from your Hosted database, first expose the remotesapi endpoint. This will set the port for a server which can expose the databases in the sql-server over remotesapi.

Note that this will only work for deployments that use a Web PKI certificate.

Check both the "Use Web PKI Certificate" and "Expose remotesapi endpoint" when creating a deployment will also work.

2. Set remote password and run clone command with user flag

To authenticate against it, you have to set a DOLT_REMOTE_PASSWORD environment variable and pass along a --user flag to the dolt clone command. You can find these instructions in the Connectivity tab on your deployment page.

If you'd like to allow other SQL users to clone without giving them access to your Hosted admin username and password, you can grant them CLONE_ADMIN privileges. They will then be able to execute the above commands using their own SQL user and password.

GRANT CLONE_ADMIN ON *.* TO "[username]"@"[host]";

After running the dolt clone command, you should have a local copy of your Hosted database.

% dolt clone https://dolthub-us-housing.dbs.hosted.doltdb.com/us-housing-prices -u"username"
cloning https://dolthub-us-housing.dbs.hosted.doltdb.com/us-housing-prices
% cd us-housing-prices
% dolt sql -q "select count(*) from sales"
+----------+
| count(*) |
+----------+
| 13844603 |
+----------+

3. Sync your local copy with upstream changes

Now we can run whatever queries or schema migrations we want without affecting production. If there are updates to the database, easily sync your local copy using dolt fetch or dolt pull.

Assuming your password environment variable is still set, you can authenticate these commands to your remotesapi endpoint in the same way by passing the --user flag:

% dolt pull --user "[username]"
% dolt fetch --user "[username]"

Note that this remotesapi endpoint is currently read-only. Writes to remotesapi, such as dolt push, are not supported yet.