tableExists in
spark/sql/core/src/main/scala/org/apache/spark/sql/jdbc/JdbcUtils.scala uses
non-standard SQL (specifically, the LIMIT keyword) to determine whether a
table exists in a JDBC data source. This will cause an exception in
many/most JDBC databases that doesn't support LIMIT keyword. See
http://stackoverflow.com/questions/1528604/how-universal-is-the-limit-statement-in-sql
To check for table existence or an exception, it could be recrafted around
select 1 from $table where 0 = 1 which isn't the same (it returns an empty
resultset rather than the value '1'), but would support more data sources
and also support empty tables. The standard way to check for existence would
be to use information_schema.tables which is a SQL standard but may not work
for other JDBC data sources that support SQL, but not the
information_schema.
As an aside, I tried to submit a bug through JIRA, but using Create
Bug-Quick or Bug-Detailed through the Spark issue-tracker webpage appears to
submit the bug as a bug against the Atlas project, rather than the Spark
project.
Cheers, Bob
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