docs/gitbook/getting_started/permanent-functions.md

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Hive v0.13 or later supports [permanent functions](https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-Create/DropFunction) that live across sessions.

Permanent functions are useful when you are using Hive through Hiveserver or to avoid hivemall installation for each session.

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# Put hivemall jar to HDFS

First, put hivemall jar to HDFS as follows:
```sh
hadoop fs -mkdir -p /apps/hivemall
hadoop fs -put hivemall-with-dependencies.jar /apps/hivemall
```

# Create permanent functions

_The following is an auxiliary step to define functions for hivemall databases, not for the default database._
```sql
CREATE DATABASE IF NOT EXISTS hivemall;
USE hivemall;
```

Then, create permanent functions using [define-all-as-permanent.hive](https://github.com/myui/hivemall/blob/master/resources/ddl/define-all-as-permanent.hive), a DDL script to define permanent UDFs.
```sql
set hivevar:hivemall_jar=hdfs:///apps/hivemall/hivemall-with-dependencies.jar;

source /tmp/define-all-as-permanent.hive;
```

# Confirm functions

```sql
show functions "hivemall.*";

> hivemall.adadelta
> hivemall.adagrad
```

> #### Caution
>
> You need to specify "hivemall." prefix to call hivemall UDFs in your queries if UDFs are loaded into non-default scheme, in this case _hivemall_.