the relatively small batch size of 128 was chosen so that if we have
a set of keys like
a/1
a/2
...
a/100000
b
c
list operations would not have to walk 100k keys inside of a/ before
skipping to b. unfortunately, iteration is also used by the metainfo
loop. in that case, it's doing a recursive listing, and so there's
no need to skip large prefixes. thus, we can use a bigger batch
size when recursive listing is requested.
Change-Id: I87cf1ba385b6eb2928c5b7cc5e0f7a8c7bd126d9
this will allow us to inspect the type of `db.Driver()` on *sql.DB
connections to correctly differentiate between pg and crdb conns.
as a bonus, this moves all concerns about when to replace "cockroach://"
with "postgres://" out of view, letting the thin shim "driver" take care
of that.
Change-Id: Ib24103ab7c508231e681f89a7321b623e4e125e9