# JDBC Connector Setup Instructions With Optional GSSAPI You can use GSSAPI authentication via the [The SingleStore JDBC Driver](https://docs.singlestore.com/db/v9.1/developer-resources/connect-with-application-development-tools/connect-with-java-jdbc/the-singlestore-jdbc-driver.md). Prerequisites * Configure SingleStore to use GSSAPI. Refer to [Kerberos Authentication](https://docs.singlestore.com/db/v9.1/security/authentication/kerberos-authentication.md) for information on third-party authentication using GSSAPI. * Install Java and Java SDK (`java` and `javac` binaries are available). ## Configure Authentication The following instructions are for a Red Hat Distribution. The concepts of this installation and configuration can be applied elsewhere. 1. Download the latest version of the SingleStore JDBC Driver `.jar` from [GitHub](https://github.com/memsql/S2-JDBC-Connector/releases/latest). 2. Add the following Java source code sample to a file named `Query.java`. > **📝 Note**: The code is the same for regular and Kerberos connections since the connector is porting the C extensions. This is because the SingleStore server checks grants to confirm if the user is authenticated using GSSAPI and the client C extensions have an attached handler for GSSAPI that runs independent of the third-party connector. ```java import java.net.URLEncoder; import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; import java.sql.ResultSet; class Query { // Arguments: // args[0]: the kerberos principal name with which to connect to memsqld public static void main (String[] args) { if (args.length != 1) { System.err.println("Wrong number of arguments."); System.exit(1); } try { StringBuilder url = new StringBuilder("jdbc:singlestore://127.0.0.1:3306/information_schema?user="); url.append(URLEncoder.encode(args[0], "UTF-8")); String url_string = url.toString(); System.err.println("Connection url " + url_string); Connection conn = DriverManager.getConnection(url_string); Statement stmt = conn.createStatement(); ResultSet rs; rs = stmt.executeQuery("select query_text from mv_queries"); while (rs.next()) { String qt = rs.getString("query_text"); System.out.println("query text: " + qt); } conn.close(); System.exit(0); } catch (Exception e) { System.err.println("Got an exception!"); System.err.println(e.getMessage()); e.printStackTrace(System.out); System.exit(1); } } } ``` This example uses the `/tmp/Query.java` file. To test against something other than localhost, change `127.0.0.1` (in the code above) to the IP of your choice. 3. Compile the source against the SingleStore JDBC Driver jar. Replace `x.x.x` in the following command with the SingleStore JDBC Driver version. ```shell javac -cp ./singlestore-jdbc-client-x.x.x.jar /Query.java ``` This command generates a file named `Query.class`. The `-cp` flag in the command specifies the `classpath`. It should be the path to the SingleStore JDBC Driver jar. 4. Run the `java` binary against the SingleStore JDBC Driver jar. The classpath should include the path to `Query.class` and `singlestore-jdbc-client-x.x.x.jar`. Substitute `kerberos_principal_name` with your Kerberos user and `x.x.x` with the SingleStore JDBC Driver version in the following command. ```shell java -cp ./singlestore-jdbc-client-x.x.x.jar:. Query ``` Here's a sample output: ```shell [ec2-user ~]$ java -cp "/tmp/singlestore-jdbc-client-x.x.x.jar:/tmp" Query "tron" Connection url jdbc:singlestore://127.0.0.1:3306/information_schema?user=tron Debug is true storeKey false useTicketCache true useKeyTab false doNotPrompt true ticketCache is null isInitiator true KeyTab is null refreshKrb5Config is false principal is null tryFirstPass is false useFirstPass is false storePass is false clearPass is false Acquire TGT from Cache Principal is tron@LOCALHOST Commit Succeeded SELECT @@max_allowed_packet,@@system_time_zone,@@time_zone,@@auto_increment_increment SELECT @@memsql_id SELECT @@memsql_version SELECT ACTIVITY_NAME, QUERY_TEXT, PLAN_WARNINGS, PLAN_INFO FROM INFORMATION_SCHEMA.LMV_QUERIES SELECT WITH(binary_serialization=1, binary_serialization_internal=1) `_WM_AGG_TABLE`.`AGGREGATOR_ACTIVITY_NAME` AS `aggregator_activity_name`, SUM(`_WM_AGG_TABLE`.`ELAPSED_TIME_MS`) AS `elapsed_time_ms`, SUM(`_WM_AGG_TABLE`.`SUCCESS_COUNT`) AS `numRuns` FROM `_WM_AGG_TABLE` as `_WM_AGG_TABLE` GROUP BY 1 OPTION(NO_QUERY_REWRITE=1, INTERPRETER_MODE=LLVM) SELECT query_text FROM mv_queries select query_text from mv_queries SELECT HEARTBEAT_NO_LOGGING agg.AGGREGATOR_ACTIVITY_NAME, coalesce(sum(leaves.memory_bs)*1000/agg.elapsed_time_ms/0x400/0x400, 0):>bigint,coalesce(agg.elapsed_time_ms/agg.numRuns, @):>bigint as avg_runtime, coalesce(sum(leaves.cpu_time_ms)/agg.numRuns, @):>bigint as avg_cpu_time FROM (select aggregator_activity_name, sum(elapsed_time_ms) as elapsed_time_ms, sum(success_count) as numRuns from information_schema._WM_AGG_TABLE group by 1) agg join information_schema._WM_LEAF_TABLE leaves on agg.aggregator_activity_name = leaves.aggregator_activity_name group by agg.AGGREGATOR_ACTIVITY_NAME select @@version_comment limit @ SELECT @@memsql_id SELECT @@memsql_version SELECT AVAILABILITY_GROUP FROM information_schema.LEAVES JOIN information_schema.LMV_NODES ON information_schema.LEAVES.NODE_ID=information_schema.LMV_NODES.NODE_ID SELECT WITH(binary_serialization=1, binary_serialization_internal=1) `leaves_0`.`MEMORY_BS` AS `MEMORY_BS`, `leaves_0`.`CPU_TIME_MS` AS `CPU_TIME_MS`, `leaves_0`.`AGGREGATOR_ACTIVITY_NAME` AS `AGGREGATOR_ACTIVITY_NAME` FROM `_WM_LEAF_TABLE` as `leaves_0` OPTION(NO_QUERY_REWRITE=1, INTERPRETER_MODE=LLVM) SELECT SQL_NO_LOGGING 1 SELECT SQL_NO_LOGGING @@maximum_table_memory, @@maximum_memory [ec2-user ~]$ ``` To enable debug logging for Kerberos authentication, add the `-Dsun.security.krb5.debug=true -Dsun.security.jgss.debug=true` JVM argument to the command. Here’s an example, ```shell java -Dsun.security.krb5.debug=true -Dsun.security.jgss.debug=true -cp ./singlestore-jdbc-client-1.2.3.jar:. Query ``` *** Modified at: June 5, 2024 Source: [/db/v9.1/developer-resources/connect-with-application-development-tools/connect-with-java-jdbc/jdbc-connector-setup-instructions-with-optional-gssapi/](https://docs.singlestore.com/db/v9.1/developer-resources/connect-with-application-development-tools/connect-with-java-jdbc/jdbc-connector-setup-instructions-with-optional-gssapi/) (An index of the documentation is available at /llms.txt)