diff options
| -rw-r--r-- | sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala index c1a8f19313..0acea95344 100644 --- a/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala +++ b/sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala @@ -154,13 +154,14 @@ class DataFrameReader private[sql](sqlContext: SQLContext) extends Logging { * Don't create too many partitions in parallel on a large cluster; otherwise Spark might crash * your external database systems. * - * @param url JDBC database url of the form `jdbc:subprotocol:subname` + * @param url JDBC database url of the form `jdbc:subprotocol:subname`. * @param table Name of the table in the external database. * @param columnName the name of a column of integral type that will be used for partitioning. - * @param lowerBound the minimum value of `columnName` used to decide partition stride - * @param upperBound the maximum value of `columnName` used to decide partition stride - * @param numPartitions the number of partitions. the range `minValue`-`maxValue` will be split - * evenly into this many partitions + * @param lowerBound the minimum value of `columnName` used to decide partition stride. + * @param upperBound the maximum value of `columnName` used to decide partition stride. + * @param numPartitions the number of partitions. This, along with `lowerBound` (inclusive), + * `upperBound` (exclusive), form partition strides for generated WHERE + * clause expressions used to split the column `columnName` evenly. * @param connectionProperties JDBC database connection arguments, a list of arbitrary string * tag/value. Normally at least a "user" and "password" property * should be included. |