docs/sql-manual/sql-statements/Database-Administration-Statements/UNSET-VARIABLE.md

---
{
    "title": "UNSET-VARIABLE",
    "language": "en"
}
---

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## UNSET-VARIABLE

### Name

UNSET VARIABLE

### Description

This statement is used to restore Doris system variables. These system variables can be modified at global or session level.

grammar:

```sql
UNSET [SESSION|GLOBAL] VARIABLE (variable_name | ALL)
```

illustrate:

1. (variable_name | ALL): statement must be ended with a variable name or keyword `ALL`.

> Note:
>
> 1. Only ADMIN users can unset variables to take effect globally
> 2. When restore a variable with `GLOBAL`,  it only affect your current using session and new open sessions. It does not affect other current open sessions.

### Example

1. Restore value of the time zone

   ```
   UNSET VARIABLE time_zone;
   ```

2. Restore the global execution memory size

   ```
   UNSET GLOBAL VARIABLE exec_mem_limit;
   ```
3. Restore all variables globally

   ```
   UNSET GLOBAL VARIABLE ALL;
   ```
### Keywords

    UNSET, VARIABLE

### Best Practice