SQLPerformanceWarning should log hint about gathering dictionary statistics in OracleDatabase

[lukaseder]

So far, the only RDBMS that produced SQLPerformanceWarning in issues on github was Oracle. And in many cases, the problem was outdated dictionary statistics. Here seems to be a clear case (given that even trivial queries were slow):

• Slow performance when generating code #16018

Other cases:

• Warning exception slow query. #7949
• Occasionally slow code generation query on Oracle 12c #5836

See:
https://github.com/jOOQ/jOOQ/issues?q=is%3Aissue+SQLPerformanceWarning+is%3Aclosed

It would probably be helpful to hint at gathering dictionary statistics, if the database used is OracleDatabase:
https://blogs.oracle.com/optimizer/post/gathering-system-fixed-object-and-dictionary-statistics

[lukaseder]

Fixed in versions:

• 3.20.0
• 3.19.2 (SQLPerformanceWarning should log hint about gathering dictionary statistics in OracleDatabase - Merge [#16031] #16032)
• 3.18.9 (SQLPerformanceWarning should log hint about gathering dictionary statistics in OracleDatabase - Merge [#16031] #16033)
• 3.17.18 (SQLPerformanceWarning should log hint about gathering dictionary statistics in OracleDatabase - Merge [#16031] #16034)