Add Oracle connector

[eskabetxe]

oracle plugin connector

oracle has release on Maven Central the Oracle JDBC drivers

https://repo1.maven.org/maven2/com/oracle/ojdbc/ojdbc8/19.3.0.0/ojdbc8-19.3.0.0.pom

Fixes #934

[ebyhr]

Thanks for creating this PR. Left some initial comments.
Please fix the code style error.

[ERROR] src/main/java/io/prestosql/plugin/oracle/OracleClient.java:[26,8] (imports) UnusedImports: Unused import - io.prestosql.spi.type.TypeManager.
[ERROR] src/main/java/io/prestosql/plugin/oracle/OracleClient.java:[120] (regexp) RegexpMultiline: Blank line before closing brace
[ERROR] src/main/java/io/prestosql/plugin/oracle/OracleClient.java:[120] (regexp) RegexpMultiline: Multiple consecutive blank lines

Also, we need to add oracle.rst in presto-docs module and update connector.rst.

Please update the commit message as "Add Oracle connector" because we don't use past-tense. The detailed guideline is here https://github.com/prestosql/presto#development.

[eskabetxe]

@ebyhr all done..
could you check?

[ebyhr]

You can squash commits unless rebasing branch with upstream because GitHub provides us force-pushed diff. Also, please do rebase instead fo merge-commit to track upstream branch so that we can confirm the actual diff.

[eskabetxe]

@ebyhr change all the comments..

rebased and squash the commits

[ebyhr]

@eskabetxe By the way, I would invite you to the community Slack. https://prestosql.io/slack.html There is #dev channel for Presto developers.

[findepi]

Two major bullets:

• license for docker image used for testing (Add Oracle connector #1959 (comment))
  • Based on my memory, Oracle lets you use Oracle XE for dev/testing for no charge, but doesn't allow you to redistribute it. If this hasn't changed, we wouldn't be able such an image, unless it's provided directly by Oracle.
  • if this is not resolved, it limits our ability to test on CI, but is not a showstopper for this connector in general
• license for odbc jar -- the pom.xml says it's being licensed under "Oracle Free Use Terms and Conditions (FUTC)"
  • my understanding this is not compatible with Apache License, but IANAL
  • we can workaround this by shipping the connector package without the driver and let users download the driver by themselves. In maven this can be achieved by marking the dependency provided and using presto-maven-plugin's allowedProvidedDependencies option to whitelist it

cc @martint

[eskabetxe]

Hi @findepi,
about the question of licence of docker image its ok whith what @bsideup says here(#1959 (comment))?

and for the license of jar, if not compatible I can do what you say without problem, is there any example I can follow?

[RugratsJ]

@eskabetxe, the plugin built successfully, however, when using this Oracle plugin in presto, got the following errors:

presto> show schemas from rdsoracle;

Query 20200401_235740_00020_pdzzb, FAILED, 6 nodes
Splits: 87 total, 0 done (0.00%)
0:01 [0 rows, 0B] [0 rows/s, 0B/s]

Query 20200401_235740_00020_pdzzb failed: Unable to start the Universal Connection Pool: oracle.ucp.UniversalConnectionPoolException: Cannot get Connection from Datasource: java.sql.SQLException: ORA-01017: invalid username/password; logon denied

What do we need to set up in the Oracle catalog properties file?

[RugratsJ]

@eskabetxe, I guess it's because I'm trying to integrate this Oracle pool into version 331. This connection pool is however based upon version 332 snapshot, which base JDBC connectors have changed including the CredentialProvider class.

[ebyhr]

@RugratsJ I would recommend joining Community Slack so that we can talk quickly.
https://prestosql.io/slack.html

[RugratsJ]

@ebyhr, in which channel on https://prestosql.io/slack.html ?

[ebyhr]

@eskabetxe Could you confirm the CI failure? Added code or 0c13d16 might break it. How about separating PR to introduce a connection pool?

[RugratsJ]

@eskabetxe, @ebyhr, I think it's because the user and password didn't get set when creating the pds object. We will need to read from the config file for user and password when creating the PDS. I added this logic in startConnectionPool function, now it's working.

[ebyhr]

@eskabetxe I couldn't select tables created by CTAS statement by default. It seems case-sensitivity affected it. While we can access it by case-insensitive-name-matching=true, can we improve this behavior?

CTAS

presto> create table oracle.tpch.test_ctas as select * from (values ('a')) as t(c1);
CREATE TABLE: 1 row

presto> select * from oracle.tpch.test_ctas;
Query 20200403_112116_00032_fwtga failed: line 1:15: Table 'oracle.tpch.test_ctas' does not exist

presto> show tables in oracle.tpch;
   Table
-----------
 test_ctas

Oracle side

SQL> SELECT owner, status, table_name FROM all_tables where table_name = 'test_ctas';

OWNER			       STATUS	TABLE_NAME
------------------------------ -------- ------------------------------
TPCH			       VALID	test_ctas

CREATE TABLE

presto> create table oracle.tpch.test5 (c1 int);
CREATE TABLE
presto> select * from oracle.tpch.test5;
 c1
----
(0 rows)

[RugratsJ]

Do we have updated Oracle connector that integrated with Presto version 332?

[Praveen2112]

Thanks for raising this PR!!

[ebyhr]

testDataMappingSmokeTest failed due to mapping between REAL and DOUBLE

SELECT id FROM presto_tmp_609132480497 WHERE rand() = 42 OR value = REAL '567.123'

presto_tmp_609132480497 has double type (≠real).

Recently, we replaced CREATE TABLE with CTAS in this test method and the change affected it. The populated value between CT and CTAS is different in this PR (567.1229858398438 and 567.123).

I suppose we need additional REAL type mapping.

[eskabetxe]

@ebyhr fixed..

[ebyhr]

Merged, thanks for your work!

[dprophet]

OMG. @ebyhr merged it! We have an Oracle connector. Thanks, this was desperately needed.