BUG #3811: Getting multiple values from a sequence generator

The following bug has been logged online:

Bug reference: 3811
Logged by: Adriaan van Os
Email address: postgres(at)microbizz(dot)nl
PostgreSQL version: 8.2.5
Operating system: Mac OS X 10.5
Description: Getting multiple values from a sequence generator
Details:

The following has been observed In Postgres 8.2.5

1. LOCK TABLE doesn't work on a sequence
2. nextval will happily ignore ISOLATION LEVEL SERIALIZABLE of concurrent
transactions
3. nextval doesn't have an optional "increase" parameter (the increase is
always one).

Therefore, there is no way (I know of) to prevent a concurrent nextval
between a nextval and a setval call. Consequently, it is not possible to
create an atomic operation that increases nextval by a value N > 1.

I suggest an optional "increase" parameter to the nextval function. This can
make a certain kind of bulk operation and bulk import much more efficient.