spark-instrumented-optimizer/docs/sql-data-sources-troubleshooting.md
Sean Owen 754f820035 [SPARK-26918][DOCS] All .md should have ASF license header
## What changes were proposed in this pull request?

Add AL2 license to metadata of all .md files.
This seemed to be the tidiest way as it will get ignored by .md renderers and other tools. Attempts to write them as markdown comments revealed that there is no such standard thing.

## How was this patch tested?

Doc build

Closes #24243 from srowen/SPARK-26918.

Authored-by: Sean Owen <sean.owen@databricks.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>
2019-03-30 19:49:45 -05:00

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Markdown

---
layout: global
title: Troubleshooting
displayTitle: Troubleshooting
license: |
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
---
* The JDBC driver class must be visible to the primordial class loader on the client session and on all executors. This is because Java's DriverManager class does a security check that results in it ignoring all drivers not visible to the primordial class loader when one goes to open a connection. One convenient way to do this is to modify compute_classpath.sh on all worker nodes to include your driver JARs.
* Some databases, such as H2, convert all names to upper case. You'll need to use upper case to refer to those names in Spark SQL.
* Users can specify vendor-specific JDBC connection properties in the data source options to do special treatment. For example, `spark.read.format("jdbc").option("url", oracleJdbcUrl).option("oracle.jdbc.mapDateToTimestamp", "false")`. `oracle.jdbc.mapDateToTimestamp` defaults to true, users often need to disable this flag to avoid Oracle date being resolved as timestamp.