Re: Grabbing sequence values blocks in consecutive order: Need a guaranteed method.

From: Greg Rahn <>
Date: Wed, 25 Mar 2009 12:10:48 -0700
Message-ID: <>

Taking a big step back from all the suggestions, I would like to ask what is the specific level of granularity required for the ordered/gap less sequence. For example, is this for "things" withing a given application transaction? Is it across multiple "things" for application transactions? I'm also curious what the requirement (business and/or technical) for gap less sequences is?

Order implies a level of serialization and gap less order implies exclusive serialization and serialization is the bane of scalability. There was a comment made about having 2 threads, but if they serialize for the same resource, what benefit is there to that?

On Tue, Mar 24, 2009 at 10:20 AM, FmHabash <> wrote:
> I have a need for a java app to be able in some guaranteed manner to grab a block of sequence values that are consecutive in order.
> Given the fact that there can potentially be multiple sessions making such request, no session should end up interrupting another's while this sequence values block is being granted.
> I know this can be done on java side, but thought may be it can also be done on db as well.
> My initial review shows that sequences will never guarantee gapless values. If this is the case, can this still be done at least guaranteeing an ordered (not necessarily consecutive ) values?

Greg Rahn
Received on Wed Mar 25 2009 - 14:10:48 CDT

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