Consider set a lower priority for LOAD DATA read and write RPC

[overvenus]

Enhancement

LOAD DATA LOCAL INFILE ... IGNORE INTO ... may sends KvBatchGet requests that seeks lots of data. And it essentially becomes full table scan if data is load multiple times. These KvBatchGets are set normal priority, so it overwhelms TiKV read read pool and slows down other queries that involves point get or batch point get.

Reproduce:

• Prepare a large csv file.
• Repeatedly loads the file using LOAD DATA LOCAL INFILE ... IGNORE INTO ...

Two spikes are caused by LOAD DATA twice.

[lance6716]

MySQL LOAD DATA has a LOW_PRIORITY modifier https://dev.mysql.com/doc/refman/8.0/en/load-data.html , maybe we can reuse it 🤔

And do you think we should limit the batch size of KvBatchGets as alternative?

[overvenus]

LOW_PRIORITY modifier looks good to me. Limit batch size of KvBatchGets is not enough, it eventually seeks the same amount of data.

[seiya-annie]

/found customer