**What is a MySQL Deadlock?**

A MySQL deadlock is a situation where two or more transactions are waiting for each other to release a lock, resulting in a deadlock situation where all transactions are unable to proceed. In InnoDB storage engine, deadlocks are primarily caused by locking mechanisms, and are more likely to occur in high-concurrency and complex business logic scenarios.

**Causes of MySQL Deadlocks**

MySQL deadlocks typically occur at the row level. Common causes of deadlocks include:
* **Row-level locking conflicts**: When multiple transactions try to lock rows in a specific order, but the order of locking is not consistent across transactions.
* **Lock Ordering Code**: When a transaction acquires a lock on a row, but another transaction tries to acquire a lock on an adjacent row, leading to a deadlocking situation.
* **INSERT...
UPDATE ... DELETE**: Transactions that perform these types of operations on non-indexed columns can cause deadlocks.

**Consequences of Deadlocks**

Deadlocks can have serious consequences on database performance, including:
* **Increased latency**: Deadlocks can slow down queries, leading to increased latency and slower response times.
* **Resource utilization**: Deadlocks can lead to resource underutilization, as transactions are blocked waiting for locks to be released.
* **System crashes**: In extreme cases, deadlocks can cause the database to crash or shut down.

**Best Practices for Preventing Deadlocks**

To prevent deadlocks, follow these best practices:
* **Use index on frequently updated columns**: Indexing columns that are frequently updated can help reduce the likelihood of deadlocks.
* **Use row-level locking**: Implement row-level locking to reduce the chances of deadlocks.
* **Avoid long-running transactions**: Shorten transaction duration to minimize the window for potential deadlocks.
* **Monitor and analyze deadlocks**: Regularly monitor and analyze deadlock occurrences to identify patterns and root causes.

By following these best practices, you can reduce the likelihood of deadlocks and minimize their impact on your MySQL database.