> You will have lesser > slots in the cache, but the total available cache will indeed be > unchanged (half the blocks of double the size). But we have many other tables, queries to which may suffer from smaller number of blocks in buffer cache.
> To change block size is a > painful thing, because IIRC you do that at db initialization time My research shows that I can only change it in compile time. https://www.postgresql.org/docs/10/static/install-procedure.html And then initdb a new cluster... Moreover, this table/schema is not the only in the database, there is a bunch of other schemas. And we will need to dump-restore everything... So this is super-painful. > It could affect space storage, for the smaller blocks. But at which extent? As I understand it is not something about "alignment" to block size for rows? Is it only low-level IO thing with datafiles? > But before going through all this, I would first try to reload the data > with dump+restore into a new machine, and see how it behaves. Yes, this is the plan, I'll be back once I find enough disk space for my further experiments. Vlad
