Query HIVE table in pyspark

2020-02-05 06:31发布

问题:

I am using CDH5.5

I have a table created in HIVE default database and able to query it from the HIVE command.

Output

hive> use default;

OK

Time taken: 0.582 seconds


hive> show tables;

OK

bank
Time taken: 0.341 seconds, Fetched: 1 row(s)

hive> select count(*) from bank;

OK

542

Time taken: 64.961 seconds, Fetched: 1 row(s)

However, I am unable to query the table from pyspark as it cannot recognize the table.

from pyspark.context import SparkContext

from pyspark.sql import HiveContext

sqlContext = HiveContext(sc)


sqlContext.sql("use default")

DataFrame[result: string]

sqlContext.sql("show tables").show()

+---------+-----------+

|tableName|isTemporary|

+---------+-----------+

+---------+-----------+


sqlContext.sql("FROM bank SELECT count(*)")

16/03/16 20:12:13 INFO parse.ParseDriver: Parsing command: FROM bank SELECT count(*)
16/03/16 20:12:13 INFO parse.ParseDriver: Parse Completed
Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "/usr/lib/spark/python/pyspark/sql/context.py", line 552, in sql
      return DataFrame(self._ssql_ctx.sql(sqlQuery), self)
    File "/usr/lib/spark/python/lib/py4j-0.8.2.1-src.zip/py4j/java_gateway.py",   line 538, in __call__
    File "/usr/lib/spark/python/pyspark/sql/utils.py", line 40, in deco
      raise AnalysisException(s.split(': ', 1)[1])
  **pyspark.sql.utils.AnalysisException: no such table bank; line 1 pos 5**

New Error

>>> from pyspark.sql import HiveContext
>>> hive_context = HiveContext(sc)
>>> bank = hive_context.table("default.bank")
16/03/22 18:33:30 INFO DataNucleus.Persistence: Property datanucleus.cache.level2 unknown - will be ignored
16/03/22 18:33:30 INFO DataNucleus.Persistence: Property hive.metastore.integral.jdo.pushdown unknown - will be ignored
16/03/22 18:33:44 INFO DataNucleus.Datastore: The class "org.apache.hadoop.hive.metastore.model.MFieldSchema" is tagged as "embedded-only" so does not have its own datastore table.
16/03/22 18:33:44 INFO DataNucleus.Datastore: The class "org.apache.hadoop.hive.metastore.model.MOrder" is tagged as "embedded-only" so does not have its own datastore table.
16/03/22 18:33:48 INFO DataNucleus.Datastore: The class "org.apache.hadoop.hive.metastore.model.MFieldSchema" is tagged as "embedded-only" so does not have its own datastore table.
16/03/22 18:33:48 INFO DataNucleus.Datastore: The class "org.apache.hadoop.hive.metastore.model.MOrder" is tagged as "embedded-only" so does not have its own datastore table.
16/03/22 18:33:50 INFO DataNucleus.Datastore: The class "org.apache.hadoop.hive.metastore.model.MResourceUri" is tagged as "embedded-only" so does not have its own datastore table.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/spark/python/pyspark/sql/context.py", line 565, in table
    return DataFrame(self._ssql_ctx.table(tableName), self)
  File "/usr/lib/spark/python/lib/py4j-0.8.2.1-src.zip/py4j/java_gateway.py", line 538, in __call__
  File "/usr/lib/spark/python/pyspark/sql/utils.py", line 36, in deco
    return f(*a, **kw)
  File "/usr/lib/spark/python/lib/py4j-0.8.2.1-src.zip/py4j/protocol.py", line 300, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o22.table.
: org.apache.spark.sql.catalyst.analysis.NoSuchTableException
    at org.apache.spark.sql.hive.client.ClientInterface$$anonfun$getTable$1.apply(ClientInterface.scala:123)
    at org.apache.spark.sql.hive.client.ClientInterface$$anonfun$getTable$1.apply(ClientInterface.scala:123)
    at scala.Option.getOrElse(Option.scala:120)
    at org.apache.spark.sql.hive.client.ClientInterface$class.getTable(ClientInterface.scala:123)
    at org.apache.spark.sql.hive.client.ClientWrapper.getTable(ClientWrapper.scala:60)
    at org.apache.spark.sql.hive.HiveMetastoreCatalog.lookupRelation(HiveMetastoreCatalog.scala:406)
    at org.apache.spark.sql.hive.HiveContext$$anon$1.org$apache$spark$sql$catalyst$analysis$OverrideCatalog$$super$lookupRelation(HiveContext.scala:422)
    at org.apache.spark.sql.catalyst.analysis.OverrideCatalog$$anonfun$lookupRelation$3.apply(Catalog.scala:203)
    at org.apache.spark.sql.catalyst.analysis.OverrideCatalog$$anonfun$lookupRelation$3.apply(Catalog.scala:203)
    at scala.Option.getOrElse(Option.scala:120)
    at org.apache.spark.sql.catalyst.analysis.OverrideCatalog$class.lookupRelation(Catalog.scala:203)
    at org.apache.spark.sql.hive.HiveContext$$anon$1.lookupRelation(HiveContext.scala:422)
    at org.apache.spark.sql.SQLContext.table(SQLContext.scala:739)
    at org.apache.spark.sql.SQLContext.table(SQLContext.scala:735)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:231)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:379)
    at py4j.Gateway.invoke(Gateway.java:259)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:133)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.GatewayConnection.run(GatewayConnection.java:207)
    at java.lang.Thread.run(Thread.java:745)

thanks

回答1:

We cannot pass the Hive table name directly to Hive context sql method since it doesn't understand the Hive table name. One way to read Hive table in pyspark shell is:

from pyspark.sql import HiveContext
hive_context = HiveContext(sc)
bank = hive_context.table("default.bank")
bank.show()

To run the SQL on the hive table: First, we need to register the data frame we get from reading the hive table. Then we can run the SQL query.

bank.registerTempTable("bank_temp")
hive_context.sql("select * from bank_temp").show()


回答2:

SparkSQL gets shipped with its own metastore (derby), so that it can work even if hive is not installed on the system.This is the default mode.

In the above question, you created a table in hive. You get the table not found error because SparkSQL is using its default metastore which doesn't have metadata of your hive table.

If you want SparkSQL to use the hive metastore instead and access hive tables, then you have to add hive-site.xml in spark conf folder.



回答3:

At my problem, cp the hive-site.xml to your $SPARK_HOME/conf, and cp the mysql-connect-java-*.jar to your $SPARK_HOME/jars, this solution solved my problem.



回答4:

Not sure, if this is not resolved yet, I was checking out the pyspark kernel with Livy integration and this is how i tested the hive configuration

from pyspark.sql import Row
from pyspark.sql import HiveContext
sqlContext = HiveContext(sc)
test_list = [('A', 25),('B', 20),('C', 25),('D', 18)]
rdd = sc.parallelize(test_list)
people = rdd.map(lambda x: Row(name=x[0], age=int(x[1])))
schemaPeople = sqlContext.createDataFrame(people)
# Register it as a temp table
sqlContext.registerDataFrameAsTable(schemaPeople, "test_table")
sqlContext.sql("show tables").show()


Output:
--------
+--------+----------+-----------+
|database| tableName|isTemporary|
+--------+----------+-----------+
|        |test_table|       true|
+--------+----------+-----------+

 Now one can query it in many different ways,
 1. jupyter kernel(sparkmagic syntax): 
    %%sql 
    SELECT * FROM test_table limit 4
 2. Using default HiveContext:
    sqlContext.sql("Select * from test_table").show()


回答5:

you can use sqlCtx.sql. The hive-site.xml should be copied to spark conf path.

my_dataframe = sqlCtx.sql("Select * from categories") my_dataframe.show()



标签: hive pyspark