# Percona Toolkit UDFs

Three *Percona Toolkit* UDFs that provide faster checksums are provided:

* `libfnv1a_udf`

* `libfnv_udf`

* `libmurmur_udf`

## Version specific information

* 8.0.12-1: The feature was ported from *Percona Server for MySQL* 5.7.

## Other information

* Author/Origin: Baron Schwartz

## Installation

These UDFs are part of the *Percona Server for MySQL* packages. To install one of the UDFs into the server, execute one of the following commands, depending on which UDF you want to install:

```sql
mysql -e "CREATE FUNCTION fnv1a_64 RETURNS INTEGER SONAME 'libfnv1a_udf.so'"
mysql -e "CREATE FUNCTION fnv_64 RETURNS INTEGER SONAME 'libfnv_udf.so'"
mysql -e "CREATE FUNCTION murmur_hash RETURNS INTEGER SONAME 'libmurmur_udf.so'"
```

Executing each of these commands will install its respective UDF into the server.

## Troubleshooting

If you get the error:

??? example "Error message"

    ```text
    ERROR 1126 (HY000): Can't open shared library 'fnv_udf.so' (errno: 22 fnv_udf.so: cannot open shared object file: No such file or directory)
    ```

Then you may need to copy the .so file to another location in your system. Try both `/lib` and `/usr/lib`. Look at your environment’s `$LD_LIBRARY_PATH` variable for clues. If none is set, and neither `/lib` nor `/usr/lib` works, you may need to set `LD_LIBRARY_PATH` to `/lib` or `/usr/lib`.

## Other reading

* *Percona Toolkit* [documentation](https://docs.percona.com/percona-toolkit/)