How to read dirty data in mysql

MySQL method of reading dirty data: Set the transaction isolation level to READ UNCOMMITTED. This isolation level allows reading of uncommitted modifications by other concurrent transactions. Risks include: data inconsistency and phantom reading problems. It is recommended to only read dirty data when data consistency is not important and the requirements for latency and throughput are high.

MySQL reads dirty data

Dirty data refers to modifications made by uncommitted transactions in the database . In a non-isolated environment (READ UNCOMMITTED), a transaction can read uncommitted modifications of other concurrent transactions.

How to read dirty data

To read dirty data, you need to set the transaction isolation level to READ UNCOMMITTED. This can be achieved by:

<code class="sql">SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;</code>

Risks and Considerations

Reading dirty data may result in the following risks:

• Data inconsistency: The dirty data read may change due to other transaction commits or rollbacks.
• Phantom read problem: Other transactions may insert or delete data, causing the read results to change.

Therefore, reading dirty data is only recommended if:

• Data consistency is not a critical factor.
• Applications require low latency or high throughput.

Other Notes

• READ UNCOMMITTED level of isolation only guarantees that transactions cannot read locked data.
• Other isolation levels (such as READ COMMITTED) can provide stronger isolation, but at the expense of performance.
• It is recommended to use the READ UNCOMMITTED level with caution in transactions and understand its associated risks.

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