---
title: "Percona server UDF fast hashing with fnv1a_64"
date: "2013-04-11"
path: "/127-percona-server-udf-fast-hashing-with-fnv1a_64.html"
section: "/ramblings"
aliases:
  - "/127"
  - "/127-percona-server-udf-fast-hashing-with-fnv1a_64"
  - "/127.html"
  - "/ramblings/127-percona-server-udf-fast-hashing-with-fnv1a_64.html"
---

Percona Server is distributed with several useful UDF (User Defined Function) from Percona Toolkit. Three of the Percona Toolkit UDFs that provide faster checksums are:

- fnv_udf
- fnv1a_udf
- murmur_udf

Initially you will need the Percona Toolkit installing: `apt-get install percona-toolkit`

You can then choose to run one of the following commands to create these functions:

```
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'"
```

Based on some \*loose\* research we chose the fnv1a_64 function so make sure the ".so" exists like so:

```
root@bilberry:~# locate fnv1a_udf.so
/usr/lib/mysql/plugin/libfnv1a_udf.so
/usr/lib/mysql/plugin/libfnv1a_udf.so.0
/usr/lib/mysql/plugin/libfnv1a_udf.so.0.0.0
```

Then run the command:

```
mysql -u root -ppass -e "CREATE FUNCTION fnv1a_64 RETURNS INTEGER SONAME 'fnv1a_udf.so'"
```

This will show the file does not exist in that name so update the command to match the file name:

```
mysql -u root -ppass -e "CREATE FUNCTION fnv1a_64 RETURNS INTEGER SONAME 'libfnv1a_udf.so'"
```

See notes here for more details:

- Percona Toolkit - http://www.percona.com/doc/percona-server/5.5/management/udf_percona_toolkit.html
- FNV1a64 - http://www.getopt.org/utils/build/api/org/getopt/util/hash/FNV1a64.html
- MurmurHash - http://en.wikipedia.org/wiki/MurmurHash