Icehouse Design Summit

This session will include the following subject(s):

Work in IceHouse around nova DB:

We done a lot of work in Havana around DB in whole OpenStack and especially Nova. I don't see any reason to stop continue improving it.


Nova is also favorite in DB related things, so it will be nice to discuss next points:
1) Use oslo.db lib

2) Switch from sqla-migrate to alembic
(we found already one approach that allows us to make this all without rewritting old migartions)

3) Keep synced models & migrations
https://review.openstack.org/#/c/42307/

4) Use in unit tests DB created from models

5) Run unit tests against all backends (not only sqlite)

6) If we implement 3 & 4 we could drop support of sqlite in migration

7) Get rid of soft delete or implement fast and safe purge engine (not archiving).

We have a lot of problems with soft deletion:
1) must have purge engine
2) bad performance
3) complicated logic

It seems that in almost all cases we are able to delete instantly records. So we should deep analyze this situatiin & probably refactor current DB to get rid of soft deletion.


8) Get from DB only what we actually need. Now we are always getting 3 columns "create_at", "updated_at", "deleted_at" (it is half of DB traffic sic.. ) and they are pretty rare used.










(Session proposed by Boris)

Next steps for database improvement:

I'd like to see a general database session in the nova track.

Proposed items to discuss:

* the database CI stuff that Josh Hesketh and I have been working on
* whether a move to alembic makes sense

(Session proposed by Michael Still)