Questions about BATs and their names in BBP's

Eyal Rozenberg E.Rozenberg at cwi.nl
Thu Nov 24 19:17:16 CET 2016


So, I'm listing the BATs in a BBP (of a TPCH database), and I'm noticing 
several strange things:

1. There's a h-u-g-e number of BATs. Actually I knew this to be the case 
already, since BBPs have so many files, but, it's still striking. 863 
BATs for a database with 61 bona fide columns (in lineitem, customer etc.)
2. There are a lot of BATs with null storage. And I do mean a lot - 514 
out of 863. What are these? why do they need to exist? And note this is 
a database in which nothing has occurred except one-time loading.
3. Most BATs have dummy generated names, e.g. tmp_547 - not, say, a 
concatenation of their table name and column name. Yet - some BATs _do_ 
have meaningful names: environment_key, sql_dsnapshots, stat_opt_calls 
and so on. Why not have meaningful names for all BATs then?

and lastly, and perhaps most importantly:

5. What's the best/most appropriate/most quick-and-dirty way of 
obtaining table and column names for those BATs which have them?
6. If it's through the storage table - is there a way to determine which 
BATs correspond to its columns (table, column, location at the very least)?


More information about the developers-list mailing list