E-MapReduce:Use the CLI to connect to Presto

Prerequisites

Before you begin, make sure you have:

• An E-MapReduce (EMR) cluster of V3.45.0, V5.11.0, or a later minor version with the Presto service deployed. For more information, see Create a cluster.

Common clusters

1. Log on to the cluster over SSH. For more information, see Log on to a cluster.

2. Open the Presto CLI:

   presto --server master-1-1:8889

   A successful connection displays the presto> prompt. Run help to see all supported commands, or quit; to exit.

3. Explore available data sources before running queries. If you don't know which catalogs and schemas are available, run the following commands:

   -- List all catalogs (data sources)
   show catalogs;
   
   -- List schemas in a catalog
   show schemas from <catalog>;
   
   -- Set a default catalog and schema to avoid typing the full path each time
   use <catalog>.<schema>;

   You can also view all catalogs on the Configure tab of the Presto service page in the EMR console.

4. Query table data:

   Parameter	Description
   <catalog>	The data source to connect to
   <schema>	The database to query
   <table>	The table to query

   select * from <catalog>.<schema>.<table>;

   For example, to query the test table in the default Hive database:

   select * from hive.default.test;

5. (Optional) Exit the Presto CLI:

   quit;

High-security clusters

1. Log on to the cluster over SSH. For more information, see Log on to a cluster.

2. Open the Presto CLI with Kerberos authentication:

   presto --server https://${FQDN}:7779 \
     --krb5-config-path /etc/krb5.conf \
     --keystore-path /etc/emr/presto-conf/keystore \
     --keystore-password ${pwd} \
     --krb5-keytab-path /etc/emr/presto-conf/presto.keytab \
     --krb5-principal presto/${FQDN}@${REALM} \
     --krb5-remote-service-name presto \
     --user presto/${FQDN}

   The following table describes the parameters you need to supply:

   Parameter	Description
   ${FQDN}	The fully qualified domain name (FQDN) of the master-1-1 node, in the format master-1-1.c-xxxxxxx.cn-xxxxxx.emr.aliyuncs.com. Run hostname -f to get the value.
   --krb5-config-path	The path to the Kerberos configuration file. Fixed value: /etc/krb5.conf. Corresponds to http.authentication.krb5.config in config.properties.
   --keystore-path	The path to the TLS keystore. Fixed value: /etc/emr/presto-conf/keystore. Corresponds to http-server.https.keystore.path in config.properties.
   --keystore-password	The keystore password. Corresponds to http-server.https.keystore.key in config.properties. Run the following command on the master-1-1 node to get the value: awk -F= '/http-server.https.keystore.key/{print $2}' ${PRESTO_CONF_DIR}/config.properties
   --krb5-keytab-path	The path to the Kerberos keytab file. Fixed value: /etc/emr/presto-conf/presto.keytab. Corresponds to http.server.authentication.krb5.keytab in config.properties.
   ${REALM}	The Kerberos realm. Unlike the Kerberos realm for Trino, the Kerberos realm for Presto is not stored in the Presto configuration file. Check /etc/krb5.conf for the value — in EMR, the format is EMR.C-XXXXXX.COM.
   --krb5-remote-service-name	Fixed value: presto. Corresponds to http.server.authentication.krb5.service-name in config.properties.

3. Query table data:

   select * from <catalog>.<schema>.<table>;

   For parameter descriptions and examples, see step 4 in Common clusters.

4. (Optional) Exit the Presto CLI:

   quit;

What's next

Use Java Database Connectivity (JDBC) to connect to Presto for querying, analyzing, and processing complex data, or to integrate query results into Java applications. For more information, see Use JDBC.