# sp\$1babelfish\$1volatility
<a name="sp_babelfish_volatility"></a>

PostgreSQL function volatility helps the optimizer for a better query execution which when used in parts of certain clauses has a significant impact on query performance. 

## Syntax
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```
sp_babelfish_volatility ‘function_name’, ‘volatility’
```

## Arguments
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 *function\$1name (optional)*   
You can either specify the value of this argument with a two-part name as `schema_name.function_name`or only the `function_name`. If you specify only the `function_name`, the schema name is the default schema for the current user.

 *volatility (optional)*   
The valid PostgreSQL values of volatility are `stable`, `volatile`, or `immutable`. For more information, see [https://www.postgresql.org/docs/current/xfunc-volatility.html](https://www.postgresql.org/docs/current/xfunc-volatility.html)

**Note**  
When `sp_babelfish_volatility` is called with `function_name` which has multiple definitions, it will throw an error.

## Result set
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If the parameters are not mentioned then the result set is displayed under the following columns: `schemaname`, `functionname`, `volatility`.

## Usage notes
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PostgreSQL function volatility helps the optimizer for a better query execution which when used in parts of certain clauses has a significant impact on query performance. 

## Examples
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The following examples shows how to create simple functions and later explains how to use `sp_babelfish_volatility` on these functions using different methods.

```
1> create function f1() returns int as begin return 0 end
2> go
```

```
1> create schema test_schema
2> go
```

```
1> create function test_schema.f1() returns int as begin return 0 end
2> go
```

The following example displays volatility of the functions:

```
1> exec sp_babelfish_volatility
2> go
            
schemaname  functionname volatility
----------- ------------ ----------
dbo         f1           volatile
test_schema f1           volatile
```

The following example shows how to change the volatility of the functions:

```
1> exec sp_babelfish_volatility 'f1','stable'
2> go
1> exec sp_babelfish_volatility 'test_schema.f1','immutable'
2> go
```

When you specify only the function\$1name, it displays the schema name, function name and volatility of that function. The following example displays volatility of functions after changing the values:

```
1> exec sp_babelfish_volatility 'test_schema.f1'
2> go
            
schemaname  functionname volatility
----------- ------------ ----------
test_schema f1           immutable
```

```
1> exec sp_babelfish_volatility 'f1'
2> go
            
schemaname  functionname volatility
----------- ------------ ----------
dbo         f1           stable
```

When you don't specify any argument, it displays a list of functions (schema name, function name, volatility of the functions) present in the current database:

```
1> exec sp_babelfish_volatility 
2> go
            
schemaname  functionname volatility
----------- ------------ ----------
dbo         f1           stable
test_schema f1           immutable
```