How to generate a spark sql truncate query without Only - apache-spark

Question

I am using Spark(3.0.0_preview) and reading/writing from/to GreenPlum(version 5.24). The Greenplum version 5.24 doesn't support the "truncate table only $table_name" command.
With Spark 3.0.0_preview and jdbcdriver(org.postgresql" % "postgresql" % "42.2.5), the command genearted by Spark is "truncate table only $table_name".
df.write.format("jdbc").option("url", "jdbc:postgresql://test:5432/sample")
.option("user", "sample")
.option("password", "sample")
.option("dbtable", "test.employer")
.option("truncate", true) // **Genearte truncate table only**
.mode(SaveMode.Overwrite)
.save();
I want to generate truncate command without ONLY option. As the only option is not supported by Greenplum V5.24

Answer 1

As mentioned by #mazaneicha the Spark's PostgreSQL dialect can only generate TRUNCATE ONLY
To get this working for me, I am using Scala to truncate my table. Not a good fix but would work till we upgrade to GreenPlum 6 which supports TRUNCATE TABLE ONLY
truncate(""test.employer", "jdbc:postgresql://test:5432/sample","sample","sample" )
df.write.format("jdbc").option("url", "jdbc:postgresql://test:5432/sample")
.option("user", "sample")
.option("password", "sample")
.option("dbtable", "test.employer")
.mode(SaveMode.Append)
.save();
def truncate(tableName: String, jdbcUrl: String, username: String, password:
String) = {
val connection = DriverManager.getConnection(jdbcUrl, username, password)
connection.setAutoCommit(true)
val statement = connection.createStatement()
statement.execute(s"TRUNCATE TABLE $tableName")
}