Changed JDBC string splitting delimiter

jdbc/README.md

@@ -73,6 +73,24 @@ db.passwd=admin
 
 Be sure to use your driver class, a valid JDBC connection string, and credentials to your database.
 
+For connection fail-over in a DBMS cluster specify the connection string as follows (example based on Postgres):
+
+```sh
+db.driver=org.postgresql.Driver
+db.url=jdbc:postgresql://IP1:PORT1,IP2:PORT2,IP3:PORT3/ycsb
+db.user=admin
+db.passwd=admin
+```
+
+For using multiple shards in a DBMS cluster specify the connection string as follows by using `;`as delimiter (example based on PostgreSQL):
+
+```sh
+db.driver=org.postgresql.Driver
+db.url=jdbc:postgresql://host1:port1/ycsb;jdbc:postgresql://host2:port2/ycsb
+db.user=admin
+db.passwd=admin
+```
+
 You can add these to your workload configuration or a separate properties file and specify it with ```-P``` or you can add the properties individually to your ycsb command with ```-p```.
 
 ### 5. Add your JDBC Driver to the classpath
@@ -115,8 +133,3 @@ Some JDBC drivers support re-writing batched insert statements into multi-row in
 - set JDBC driver specific connection parameter in **db.url** to enable the rewrite as shown in the examples below:
   * MySQL [rewriteBatchedStatements=true](https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-reference-configuration-properties.html) with `db.url=jdbc:mysql://127.0.0.1:3306/ycsb?rewriteBatchedStatements=true`
   * Postgres [reWriteBatchedInserts=true](https://jdbc.postgresql.org/documentation/head/connect.html#connection-parameters) with `db.url=jdbc:postgresql://127.0.0.1:5432/ycsb?reWriteBatchedInserts=true`
-
-
-
-
-

jdbc/src/main/java/com/yahoo/ycsb/db/JdbcDBClient.java

@@ -200,7 +200,10 @@ public void init() throws DBException {
       }
       int shardCount = 0;
       conns = new ArrayList<Connection>(3);
-      final String[] urlArr = urls.split(",");
+      // for a longer explanation see the README.md
+      // semicolons aren't present in JDBC urls, so we use them to delimit
+      // multiple JDBC connections to shard across.
+      final String[] urlArr = urls.split(";");
       for (String url : urlArr) {
         System.out.println("Adding shard node URL: " + url);
         Connection conn = DriverManager.getConnection(url, user, passwd);