I doubt raising the priority of sweep/garbage
threads would yield good side effects for a
database under heavy transaction load. It probably
wouldn't make a difference on a single user or low
load system.

It's been a while but, I recall preaching to
developers, that if they designed their applications
transactions to behave well that InterBase would
scream along without a hitch.

The versioning engine is a blessing. It can be
a curse as well if you are lazy or careless with
your transaction management.

Either way, I'm not in favor of exposing this as
a configuration parameter.

Markus




--- In IB-Architect@egroups.com, "Leyne, Sean"
<InterbaseArchitecture@a...> wrote:

> Dmitry,
>
> This question should, with all deference to Ann, be better

addressed to

> Charlie C, since I expect that he either wrote or was keenly

involved in

> the architecture of these new IB 6.0 features.
>
> I, like you, will keenly await him response.
>
>
> Sean
>
> -----Original Message-----
> From: Dmitry Kuzmenko [mailto:dima@d...]
> Sent: Wednesday, January 17, 2001 7:56 AM
> To: IB-Architect@egroups.com
> Subject: Re: [IB-Architect] New feature request (thread

priority)

>
> Hello, Ann!
>
> "Ann W. Harrison" wrote:
> >
> > At 01:16 PM 11/25/2000 +0100, Toni Martir wrote:
> >
> > >The feature request is to create a new transaction parameter

option

> like:
> > >
> > >tpb_high_priority
> > >tpb_low_priority
> >
> > Jim has just explained the first issue I have with this proposal -
> > low priority threads blocking high priority threads and unable to
> > run because of their priority.
>
> I saw in sources that sweep thread is starting with LOW priority.

Does

> this mean
> that sweep will never end if there are other activity on the server?
> I've already asked this question at

sourceforge.net/projects/firebird,

> but
> nobody answered.
>
> According to your great posting about very long garbage collection

when

> there are
> non-unique index with a lot of duplicates, seems that setting sweep
> thread priority
> to LOW is not a great idea.
> Does anybody have tested sweep process with low priority? Maybe it

is

> better to
> allow DBA to configure priority of sweep thread in IBCONFIG?
>
> p.s. another thing I saw in sources is garbage collector thread with
> MIDDLE priority.
> Is there any description what is the difference between sweep and
> garbage collector's threads,
> and why their priority LOW and MIDDLE, and how this will affect
> performance on production
> databases?
>
> --
> Dmitry Kuzmenko, Epsylon Technologies.
>
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