Users currently have to provide the full class name for external data sources, like:
`sqlContext.read.format("com.databricks.spark.avro").load(path)`
This allows external data source packages to register themselves using a Service Loader so that they can add custom alias like:
`sqlContext.read.format("avro").load(path)`
This makes it so that using external data source packages uses the same format as the internal data sources like parquet, json, etc.
Author: Joseph Batchik <joseph.batchik@cloudera.com>
Author: Joseph Batchik <josephbatchik@gmail.com>
Closes#7802 from JDrit/service_loader and squashes the following commits:
49a01ec [Joseph Batchik] fixed a couple of format / error bugs
e5e93b2 [Joseph Batchik] modified rat file to only excluded added services
72b349a [Joseph Batchik] fixed error with orc data source actually
9f93ea7 [Joseph Batchik] fixed error with orc data source
87b7f1c [Joseph Batchik] fixed typo
101cd22 [Joseph Batchik] removing unneeded changes
8f3cf43 [Joseph Batchik] merged in changes
b63d337 [Joseph Batchik] merged in master
95ae030 [Joseph Batchik] changed the new trait to be used as a mixin for data source to register themselves
74db85e [Joseph Batchik] reformatted class loader
ac2270d [Joseph Batchik] removing some added test
a6926db [Joseph Batchik] added test cases for data source loader
208a2a8 [Joseph Batchik] changes to do error catching if there are multiple data sources
946186e [Joseph Batchik] started working on service loader
This PR includes the following changes:
### SPARK-8862: Add basic instrumentation to each SparkPlan operator
A SparkPlan can override `def accumulators: Map[String, Accumulator[_]]` to expose its metrics that can be displayed in UI. The UI will use them to track the updates and show them in the web page in real-time.
### SparkSQLExecution and SQLSparkListener
`SparkSQLExecution.withNewExecutionId` will set `spark.sql.execution.id` to the local properties so that we can use it to track all jobs that belong to the same query.
SQLSparkListener is a listener to track all accumulator updates of all tasks for a query. It receives them from heartbeats can the UI can query them in real-time.
When running a query, `SQLSparkListener.onExecutionStart` will be called. When a query is finished, `SQLSparkListener.onExecutionEnd` will be called. And the Spark jobs with the same execution id will be tracked and stored with this query.
`SQLSparkListener` has to store all accumulator updates for tasks separately. When a task fails and starts to retry, we need to drop the old accumulator updates. Because we can not revert our changes to an accumulator, we have to maintain these accumulator updates by ourselves so as to drop accumulator updates for a failed task.
### SPARK-8862: A new SQL tab
Includes two pages:
#### A page for all DataFrame/SQL queries
It will show the running, completed and failed queries in 3 tables. It also displays the jobs and their links for a query in each row.
#### A detail page for a DataFrame/SQL query
In this page, it also shows the SparkPlan metrics in real-time. Run a long-running query, such as
```
val testData = sc.parallelize((1 to 1000000).map(i => (i, i.toString))).toDF()
testData.select($"_1").filter($"_1" < 1000).foreach(_ => Thread.sleep(60))
```
and you will see the metrics keep updating in real-time.
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Author: zsxwing <zsxwing@gmail.com>
Closes#7774 from zsxwing/sql-ui and squashes the following commits:
5a2bc99 [zsxwing] Remove UISeleniumSuite and its dependency
57d4cd2 [zsxwing] Use VisibleForTesting annotation
cc1c736 [zsxwing] Add SparkPlan.trackNumOfRowsEnabled to make subclasses easy to track the number of rows; fix the issue that the "save" action cannot collect metrics
3771ab0 [zsxwing] Register SQL metrics accmulators
3a101c0 [zsxwing] Change prepareCalled's type to AtomicBoolean for thread-safety
b8d5605 [zsxwing] Make prepare idempotent; call children's prepare in SparkPlan.prepare; change doPrepare to def
4ed11a1 [zsxwing] var -> val
332639c [zsxwing] Ignore UISeleniumSuite and SQLListenerSuite."no memory leak" because of SPARK-9580
bb52359 [zsxwing] Address other commens in SQLListener
c4d0f5d [zsxwing] Move newPredicate out of the iterator loop
957473c [zsxwing] Move STATIC_RESOURCE_DIR to object SQLTab
7ab4816 [zsxwing] Make SparkPlan accumulator API private[sql]
dae195e [zsxwing] Fix the code style and comments
3a66207 [zsxwing] Ignore irrelevant accumulators
b8484a1 [zsxwing] Merge branch 'master' into sql-ui
9406592 [zsxwing] Implement the SparkPlan viz
4ebce68 [zsxwing] Add SparkPlan.prepare to support BroadcastHashJoin to run background work in parallel
ca1811f [zsxwing] Merge branch 'master' into sql-ui
fef6fc6 [zsxwing] Fix a corner case
25f335c [zsxwing] Fix the code style
6eae828 [zsxwing] SQLSparkListener -> SQLListener; SparkSQLExecutionUIData -> SQLExecutionUIData; SparkSQLExecution -> SQLExecution
822af75 [zsxwing] Add SQLSparkListenerSuite and fix the issue about onExecutionEnd and onJobEnd
6be626f [zsxwing] Add UISeleniumSuite to test UI
d02a24d [zsxwing] Make ExecutionPage private
23abf73 [zsxwing] [SPARK-8862][SPARK-8862][SQL] Add basic instrumentation to each SparkPlan operator and add a new SQL tab
Joseph Batchik
zsxwing
