[Monetdb-developers] Re: [MonetDB-users] speed comparison off inserts and deletes, and db size question

Joel Reymont 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  
guide?

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?

     Thanks, Joel

--
http://wagerlabs.com/uptick







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