A user is locked out and I want to restore their access

User lockout information is stored in pm_project_user_params. To unlock, just execute this:
DELETE FROM pm_project_user_params WHERE user_id=[your user] AND param_name_cd='LOCKEDOUT'

Obfuscated users are automatically locked out if they ever perform the same query more than a certain number of times. This defaults to 7 and can be configured by the edu.harvard.i2b2.crc.lockout.setfinderquery.count parameter in the hive_cell_params table. To allow a user to repeat the same query after the lockout number of attempts, you must delete the previous queries from the qt_query_master table.

Encounter set breakdowns fail but other breakdowns work fine

Check that your QT_Patient_enc_collection has less than two billion rows. If it grows too large over time, generating new encounter sets will fail. Delete unneeded encounter sets.

Example query: SELECT max(PATIENT_ENC_COLL_ID) FROM [dbo].[QT_PATIENT_ENC_COLLECTION]

How do I contribute to the i2b2 code?

1. Create a JIRA issue
2. Make a GitHub pull request and reference the JIRA issue in the commit comment (e.g., "CORE-589: Fixed hyperspeed drive rotor").
3. Attest to the DCO (can be done by including text like 'I attest to https://developercertificate.org/' in the Pull Request)
4. E-mail someone on the i2b2 core development team (Mike Mendis or Jeff Klann at the time of writing).

Additionally, your contribution:

1. Must be tested
2. Must include unit tests (for new features)
3. Must include documentation (can be part of the pull request)