Getting Data into H2O¶
Getting your data into H2O is the first step toward building and scoring your models. Whether you’re importing data, uploading data, or retrieving data from HDFS or S3, be sure that your data is compatible with H2O.
Supported File Formats¶
H2O currently supports the following file types:
- CSV (delimited) files
- ORC
- SVMLight
- ARFF
- XLS
- XLSX
- Avro version 1.8.0 (without multifile parsing or column type modification)
- Parquet
Notes:
- ORC is available only if H2O is running as a Hadoop job.
- Users can also import Hive files that are saved in ORC format.
Data Sources¶
H2O supports data ingest from various data sources. Natively, a local file system, remote file systems, HDFS, S3, and some relational databases are supported. Additional data sources can be accessed through a generic HDFS API, such as Alluxio or OpenStack Swift.
Default Data Sources¶
- Local File System
- Remote File
- S3
- HDFS
- JDBC
Local File System¶
Data from a local machine can be uploaded to H2O via a push from the client. For more information, refer to Uploading a File.
Remote File¶
Data that is hosted on the Internet can be imported into H2O by specifying the URL. For more information, refer to Importing a File.
HDFS-like Data Sources¶
Various data sources can be accessed through an HDFS API. In this case, a library providing access to a data source needs to be passed on a command line when H2O is launched. (Reminder: Each node in the cluster must be launched in the same way.) The library must be compatible with the HDFS API in order to be registered as a correct HDFS FileSystem
.
Alluxio FS¶
Required Library
To access Alluxio data source, an Alluxio client library that is part of Alluxio distribution is required. For example, alluxio-1.3.0/core/client/target/alluxio-core-client-1.3.0-jar-with-dependencies.jar
.
H2O Command Line
java -cp alluxio-core-client-1.3.0-jar-with-dependencies.jar:build/h2o.jar water.H2OApp
URI Scheme
An Alluxio data source is referenced using alluxio://
schema and location of Alluxio master. For example,
alluxio://localhost:19998/iris.csv
core-site.xml Configuration
Not supported.
IBM Swift Object Storage¶
Required Library
To access IBM Object Store (which can be exposed via Bluemix or Softlayer), IBM’s HDFS driver hadoop-openstack.jar
is required. The driver can be obtained, for example, by running BigInsight instances at location /usr/iop/4.2.0.0/hadoop-mapreduce/hadoop-openstack.jar
.
Note: The jar available at Maven central is not compatible with IBM Swift Object Storage.
H2O Command Line
java -cp hadoop-openstack.jar:h2o.jar water.H2OApp
URI Scheme
Data source is available under the regular Swift URI structure: swift://<CONTAINER>.<SERVICE>/path/to/file
For example,
swift://smalldata.h2o/iris.csv
core-site.xml Configuration
The core-site.xml needs to be configured with Swift Object Store parameters. These are available in the Bluemix/Softlayer management console.
<configuration>
<property>
<name>fs.swift.service.SERVICE.auth.url</name>
<value>https://identity.open.softlayer.com/v3/auth/tokens</value>
</property>
<property>
<name>fs.swift.service.SERVICE.project.id</name>
<value>...</value>
</property>
<property>
<name>fs.swift.service.SERVICE.user.id</name>
<value>...</value>
</property>
<property>
<name>fs.swift.service.SERVICE.password</name>
<value>...</value>
</property>
<property>
<name>fs.swift.service.SERVICE.region</name>
<value>dallas</value>
</property>
<property>
<name>fs.swift.service.SERVICE.public</name>
<value>false</value>
</property>
</configuration>
Google Cloud Storage Connector for Hadoop & Spark¶
Required Library
To access the Google Cloud Store Object Store, Google’s cloud storage connector, gcs-connector-latest-hadoop2.jar
is required. The official documentation and driver can be found here.
H2O Command Line
H2O on Hadoop:
hadoop jar h2o-driver.jar -libjars /path/to/gcs-connector-latest-hadoop2.jar
Sparkling Water
export SPARK_CLASSPATH=/home/nick/spark-2.0.2-bin-hadoop2.6/lib_managed/jar/gcs-connector-latest-hadoop2.jar
sparkling-water-2.0.5/bin/sparkling-shell --conf "spark.executor.memory=10g"
URI Scheme
Data source is available under the regular Google Storage URI structure: gs://<BUCKETNAME>/path/to/file
For example,
gs://mybucket/iris.csv
core-site.xml Configuration
core-site.xml must be configured for at least the following properties (class, project-id, bucketname) as shown in the example below. A full list of configuration options is found here.
<configuration>
<property>
<name>fs.gs.impl</name>
<value>com.google.cloud.hadoop.fs.gcs.GoogleHadoopFileSystem</value>
</property>
<property>
<name>fs.gs.project.id</name>
<value>my-google-project-id</value>
</property>
<property>
<name>fs.gs.system.bucket</name>
<value>mybucket</value>
</property>
</configuration>
JDBC Databases¶
Relational databases that include a JDBC (Java database connectivity) driver can be used as the source of data for machine learning in H2O. Currently supported SQL databases are MySQL, PostgreSQL, and MariaDB. Data from these SQL databases can be pulled into H2O using the import_sql_table
and import_sql_select
functions.
Refer to the following articles for examples about using JDBC data sources with H2O.
- Setup postgresql database on OSX
- Restoring DVD rental database into postgresql
- Building H2O GLM model using Postgresql database and JDBC driver
import_sql_table
¶
This function imports a SQL table to H2OFrame in memory. This function assumes that the SQL table is not being updated and is stable. Users can run multiple SELECT SQL queries concurrently for parallel ingestion.
Note: Be sure to start the h2o.jar in the terminal with your downloaded JDBC driver in the classpath:
java -cp <path_to_h2o_jar>:<path_to_jdbc_driver_jar> water.H2OApp
The import_sql_table
function accepts the following parameters:
connection_url
: The URL of the SQL database connection as specified by the Java Database Connectivity (JDBC) Driver. For example, “jdbc:mysql://localhost:3306/menagerie?&useSSL=false“table
: The name of the SQL tablecolumns
: A list of column names to import from SQL table. Default is to import all columns.username
: The username for SQL serverpassword
: The password for SQL serveroptimize
: Specifies to optimize the import of SQL table for faster imports. Note that this option is experimental.
connection_url <- "jdbc:mysql://172.16.2.178:3306/ingestSQL?&useSSL=false"
table <- "citibike20k"
username <- "root"
password <- "abc123"
my_citibike_data <- h2o.import_sql_table(connection_url, table, username, password)
connection_url = "jdbc:mysql://172.16.2.178:3306/ingestSQL?&useSSL=false"
table = "citibike20k"
username = "root"
password = "abc123"
my_citibike_data = h2o.import_sql_table(connection_url, table, username, password)
import_sql_select
¶
This function imports the SQL table that is the result of the specified SQL query to H2OFrame in memory. It creates a temporary SQL table from the specified sql_query. Users can run multiple SELECT SQL queries on the temporary table concurrently for parallel ingestion, and then drop the table.
Note: Be sure to start the h2o.jar in the terminal with your downloaded JDBC driver in the classpath:
java -cp <path_to_h2o_jar>:<path_to_jdbc_driver_jar> water.H2OApp
The import_sql_select
function accepts the following parameters:
connection_url
: URL of the SQL database connection as specified by the Java Database Connectivity (JDBC) Driver. For example, “jdbc:mysql://localhost:3306/menagerie?&useSSL=false“select_query
: SQL query starting with SELECT that returns rows from one or more database tables.username
: The username for the SQL serverpassword
: The password for the SQL serveroptimize
: Specifies to optimize import of SQL table for faster imports. Note that this option is experimental.
connection_url <- "jdbc:mysql://172.16.2.178:3306/ingestSQL?&useSSL=false"
select_query <- "SELECT bikeid from citibike20k"
username <- "root"
password <- "abc123"
my_citibike_data <- h2o.import_sql_select(connection_url, select_query, username, password)
connection_url = "jdbc:mysql://172.16.2.178:3306/ingestSQL?&useSSL=false"
select_query = "SELECT bikeid from citibike20k"
username = "root"
password = "abc123"
my_citibike_data = h2o.import_sql_select(connection_url, select_query, username, password)