RowMatrix的columnSimilarities()返回错误架构:初始化数据库失败

Question

在spark 2.2.0下，我在使用columnSimilarities()时遇到了错误。

下面是要重现的代码。

from pyspark.mllib.linalg.distributed import RowMatrix
rdd = sc.parallelize([[1.0,2.0,1.0],[1.0,5.0,1.0],[1.0,2.0,1.0],[4.0,2.0,4.0]])
mat = RowMatrix(rdd)
sim = mat.columnSimilarities(0.1)
sim.entries.collect()

错误是这样的(trancated.太久了。完整日志为here)。

17/08/13 10:15:19 ERROR Schema: Failed initialising database.
Unable to open a test connection to the given database. JDBC url = jdbc:derby:;databaseName=metastore_db;create=true, username = APP. Terminating connection pool (set lazyInit to true if you expect to start your database after your app). Original Exception: ------
java.sql.SQLException: Failed to start database 'metastore_db' with class loader org.apache.spark.sql.hive.client.IsolatedClientLoader$$anon$1@3234df5e, see the next exception for details.
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
    at org.apache.derby.impl.jdbc.Util.seeNextException(Unknown Source)
    at org.apache.derby.impl.jdbc.EmbedConnection.bootDatabase(Unknown Source)

这段代码运行得很好。

from pyspark.mllib.linalg.distributed import IndexedRow, IndexedRowMatrix
rdd = sc.parallelize([IndexedRow(0, [1.0,2.0,1.0]),
                      IndexedRow(1, [1.0,5.0,1.0]),
                      IndexedRow(2, [1.0,2.0,1.0]),
                      IndexedRow(3, [4.0,2.0,4.0])])
mat = IndexedRowMatrix(rdd).toRowMatrix()
sim = mat.columnSimilarities(0.1)
sim.entries.collect()

这是Spark的bug吗？

Answer 1

这是一个jdbc连接的问题，而不是columnSimilarities或MLlib的问题。

您可能需要做一些工作才能使derby连接正常运行。这里是一个起点：https://stackoverflow.com/a/40547664/1056563