Subject Re: [firebird-support] Re: firebird frozing ...
Author Alessandro GARDICH
On Fri, 2003-08-22 at 17:19, Alexander V.Nevsky wrote:
> --- In, Alessandro GARDICH
> <gremlin@g...> wrote:
> > hi to all ...
> >
> > I have many problems with firebird and ibpp
> > firebird server simply stop to work !!!
> > the process 'fbserver' is still alive, cpu occupation to 0%, all
> clients stopped,
> > difficult to make new connection ... seem is in a deadlock :( ...
> Alessandro, I can read C programs in books like "Computers for
> idiots", no more, but some observations on you code:
> 1. FB don't support Dirty Read isolation level, it is substituted to
> somewhat else by your access library, don't know to which one.
> 2. Seems you are trying to randomly update records. Nothing unusual
> you have many exceptions about lock conflicts (they are named
> deadlock even if it is simple conflict). In wait mode which you use
> scenario is:
> one transaction updated some record
> another transaction tried to do the same with this record and waits
> what first one will do - if rollback, then it will run further, if
> commit, it will raise exception.
> since you always commit, exception is always raised.

so, what's the difference in a WAIT/NO_WAIT transaction ?
I espect this behavour on a NO_WAIT transaction.

Setting WAIT make me feel Firebird have to make client wait when a
concurrent access to the same record happen.

> About freeze - you run 10 fast applications which hammers data and in
> some minutes creates a lot of versions (millions, I think) of the
> records in your table. Sooner or later garbage collection starts (or
> even sweep, if your setting for it is default 20 000 transactions) and

auto sweep set to 0 ... disabled

> server is extremely busy identifying unneeded already versions and
> freeing space occupied by them. If your real application requires such
> behaviour, I think you should re-examine it, no one RDBMS can do this,
> every one will fail by own mode - FB collecting garbage, MSSQL -
> stopping read practically all in sensible modes or impudently lying o
> read in Dirty mode.

I used in past MySQL and PostgreSQL ... with no suck kind of problems ;(
and Firebird too have to run in Linux OS.

> Best regards, Alexander.


Alessandro GARDICH <gremlin@...>