• use case: worker dies, leaves behind some in-memory tables in mysql server. These tables represent subchunks. There is a database with such materialized subchunks for each chunk that qserv materialized at a given time

• restarting mysql cleans up the contents of these tables, but the tables are not deleted. That is causing problems, because current logic is: if subchunk table exists, don't populate it
• conclusion: clean it up when worker starts
• not a scalability problem because we should not have a large number of chunks with materialized sub-chunks (in general it is slow, eg deleting 20K databases with 10 in memory tables in each takes 8 minutes. Note that each in memory table has .frm file on disk)

Large scale tests

• data reloaded, started running tests again

• once ready (soon) deploy the mysql-based kv interface, but unless integration with qserv is very smooth do not make it default right in the middle of large scale tests and the Bremerton activities.