[Monetdb-developers] Re: [MonetDB-users] speed comparison off inserts and deletes, and db size question
joelr1 at gmail.com
Wed Aug 3 11:01:04 CEST 2005
On Aug 3, 2005, at 10:40 AM, Fabian wrote:
> Most of the common MIL operators have C equivalents, like BATnew,
> BATcount, etc.
Right, I realize that. And that the extension modules are backed by C
code as well.
> You should keep in mind that if you use a (V)OID on an 32-bits
> platform, that you have a limitation of the number of rows that you
> can contain in a BAT. Also, and OID cannot be bigger than the int
> it is, so if you do need more rows, or sequence numbers that are
> higher, you will have to jump over to lng and do the sequence
> numbers yourself or something.
Is it 2^32-1 for the maximum number of rows in a BAT?
> You can never join BATs that are bigger than max(OID), so you have
> to play tricks like doing the selects on all it's subparts and then
> unioning the results, given they are small enough to be stored in
> one BAT.
Are you referring to BAT * BATkunion (BAT *b, BAT *c) in the kernel
I assume that I need to use BATkunion as opposed to BATsunion since
I'm looking only at the head column. And that the fragments satisfy
the set property since they are fragments of a larger BAT with a non-
repeating oid range. Am I thinking right?
Do I need to set any properties on the BAT for the union to work?
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