# Adjust TiDB Server Parameters (B)

+ Enable ephemeral disks
  + `oom-use-tmp-storage` 
  + `tmp-storage-path` 
  + `tmp-storage-quota` 
![center](./student-guide/diagram/23-parameter-02-01.png)
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Since v4.0.0, it supports storing temporary intermediate results in disk, reducing the probability of TiDB Server OOM caused by large SQL. Supported operators: Hash Join: #11607, Merge Join: #13256 and Sort: #12431, etc.

-oom-use-tmp-storage
     - Sets whether to enable temporary disk for certain operators when the memory usage of a single SQL statement exceeds the mem-quota-query limit. Defaults to true
   - tmp-storage-path
     - Temporary disk storage location for some operators when the memory usage of a single SQL statement exceeds the mem-quota-query limit.
     - The default value is: base64 encoded result of <OS temp folder>/<OS user ID>_tidb/<host>:<port>/<statusHost>:<statusPort>/tmp-storage.
   - tmp-storage-quota
     - tmp-storage-path Storage quota, the unit is Byte. When a single SQL statement uses a temporary disk, causing the total total temporary disk of TiDB Server to exceed tmp-storage-quota, the current SQL operation will be canceled and an Out Of Global Storage Quota! error will be returned.
     - When tmp-storage-quota is less than 0, the above checks and restrictions are not present.