Update troubleshooting for MySQL prepared statements (#23202)

* Update troubleshooting.mdx

* add eval message to troubleshooting

Author: thomasgauvin

src/content/docs/hyperdrive/observability/troubleshooting.mdx

@@ -52,6 +52,7 @@ Hyperdrive may also encounter `ErrorResponse` wire protocol messages sent by you
 | `Internal error.`                                      | Something is broken on our side.                                                                | Check for an ongoing incident affecting Hyperdrive, and contact Cloudflare Support. Retrying the query is appropriate, if it makes sense for your usage pattern.                                                                                                                               |
 | `Failed to acquire a connection from the pool.`        | Hyperdrive timed out while waiting for a connection to your database, or cannot connect at all. | If you are seeing this error intermittently, your Hyperdrive pool is being exhausted because too many connections are being held open for too long by your worker. This can be caused by a myriad of different issues, but long-running queries/transactions are a common offender.            |
 | `Server connection attempt failed: connection_refused` | Hyperdrive is unable to create new connections to your origin database.                         | A network firewall or access control list (ACL) is likely rejecting requests from Hyperdrive. Ensure you have allowed connections from the public Internet. Sometimes, this can be caused by your database host provider refusing incoming connections when you go over your connection limit. |
+| `Hyperdrive does not currently support MySQL COM_STMT_PREPARE messages` | Hyperdrive does not support prepared statements for MySQL databases. | Remove prepared statements from your MySQL queries. |
 
 ### Node errors
 
@@ -63,6 +64,10 @@ Hyperdrive may also encounter `ErrorResponse` wire protocol messages sent by you
 
 If your queries are not getting cached despite Hyperdrive having caching enabled, your driver may be configured such that your queries are not cacheable by Hyperdrive. This may happen if you are using the [Postgres.js](https://github.com/porsager/postgres) driver with [`prepare: false:`](https://github.com/porsager/postgres?tab=readme-ov-file#prepared-statements). To resolve this, enable prepared statements with `prepare: true`.
 
+| Error Message                                    | Details                                                                                                               | Recommended fixes                                                                                                            |
+| ------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
+| `Code generation from strings disallowed for this context` | The database driver you are using is attempting to use the `eval()` command, which is unsupported on Cloudflare Workers (common in `mysql2` driver). | Configure the database driver to not use `eval()`. See how to [configure `mysql2` to disable the usage of `eval()`](/hyperdrive/examples/connect-to-mysql/mysql-drivers-and-libraries/mysql2/). |
+
 ### Improve performance
 
 Having query traffic written as transactions can limit performance. This is because in the case of a transaction, the connection must be held for the duration of the transaction, which limits connection multiplexing. If there are multiple queries per transaction, this can be particularly impactful on connection multiplexing. Where possible, we recommend not wrapping queries in transactions to allow the connections to be shared more aggressively.