Date
Attendees
John Gates, Fritz Mueller, Unknown User (danielw), Vaikunth Thukral, Serge Monkewitz, Andy Salnikov, Andy Hanushevsky, Jacek Becla
Kian-Tat Lim, Mario Juric for the March sprint demo
Discussion items
March Sprint Demo
- gcov
- We could try. Hoping SQUARE will provide "central" support
- DM-854
- document duplicate column restrictions sql restrictions
- db module - improvements
- revisit implementation of createTable (and createDb?)
- current implementation confused data loader, see DM-2417
- should behave like mysql does
- created ticket: DM-2502
- db module - documentation
- doxygenize
- created ticket: DM-2503
- ddl info in metaserv
- rethink how to store metadata about schema if we have 100s of database with exactly the same schema
- created tickets DM-2504, DM-2505
- related ticket DM-2139
- also, document what is supported, cat/sql/baselineSchema.sql not enough
- created ticket DM-2506
- defining stories
- try to clearly define goals / deliverables / "acceptance list"
information exchange between processes
- usecase: need to exchange info about "index of chunks managed by the worker" between cmsd and xrootd
- considering shared memory (if we can keep it simple)
- ~1000 elements, easy, can lock entire block, auto release lock
- don't want to do it through xrootd directly, or via database. Messes up scheduling I/O heavy requests
- having it will allow incremental updates to the structure of the index of chunks without restarting the services
- create stories for Andy
- created DM-2507, DM-2508
Deleting tables
- related story: DM-1896
- worry about race condition: one czar marks table delete-pending, other czar schedules query related to that table
- decided to introduce small delay, rely on fast synchronization between czars and CSS
- considered stamping schema with "schema version", incremented when table deleted etc. Worry, it can stop perfectly valid queries that need tables not affected
- considered cross-czar communication