A follow up to this:  I implemented method (b), and ran a test that
generated 100K of ids.  This generated 1.3G worth of transaction logs.
 Question:  when can these be safely deleted?  How does one know which ones
may be deleted?  Or do they need to exist forever?

On Fri, Apr 24, 2009 at 9:52 AM, Ted Dunning <ted.dunn...@gmail.com> wrote:

> Of the methods proposed,
> a) recursive sequential files
> b) latest state file(s) that is updated using a pseudo transaction to give
> a
> range of numbers to allocate
> c) just probe zxid
> You should be pretty good with any of them.  With (a), you have to be
> careful to avoid race conditions when you get to the end of the range for
> the sub-level.  With (b), you get results of guaranteed nature although the
> highest throughput versions might have gaps (shouldn't bother you).  The
> code for this is more complex than the other implementations.  With (c),
> you
> could have potentially large gaps in the sequence, but 64 bits that
> shouldn't be a big deal.  Code for that version would be the simplest of
> any
> of them.
> On Fri, Apr 24, 2009 at 8:56 AM, Satish Bhatti <cthd2...@gmail.com> wrote:
> > Hello Ben,
> > Basically the ids are document Ids.  We will eventually have several
> > billion
> > documents in our system, and each has a unique long id.  Currently we are
> > using a database sequence to generate these longs.  Having eliminated
> other
> > uses of the database, we didn't want to keep it around just to generate
> > ids.
> >  That is why I am looking to use ZooKeeper to generate them instead.
> >
> >

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