[R-sig-DB] concurrent reading/writing in "chunks" with RSQLite (need some help troubleshooting)

[Sean Davis]

On Mon, Jul 5, 2010 at 4:09 PM, Seth Falcon <seth using userprimary.net> wrote:

>
> > Along the lines of Keith's solution, I noticed the COUNT query can be
> > VERY slow -- there is no rapid way of getting the number of rows in a
> > database table?
>
>
One way of dealing with this situation using RDBMs is to use a set of
triggers (an insert and delete pair) to keep the count in a separate table.
 I'm sure there are some examples/discussion online for creating triggers in
SQLite.

Sean



> No, there is no notion of number of rows in a table that I am aware
> of.  Note that COUNT is a way of aggregating the number of rows
> returned from a query and in general there is no way for the db to
> know how many rows will match a query.
>
> I expect Keith's solution to be quite slow.  It is executing a
> separate query each time through the loop and making a linear scan
> through the table to do the offset.
>
> + seth
>
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