thanks Thomas,

but i know exactly with statement is it, it's just the statement just after the massive delete. also just looking in the $mon table show that this statement do a lot of garbage collect ... so no mystery :(

the probleme is that this garbage collect block everything from few minutes to several hours :( and this is not acceptable for our 24x24 services. this is just for one table (where we store session cookies), this why i start to thing to move this table to another database like for exemple mysql ... but as i say i m affraid that mysql will probably have the same probleme (or other) ... need to see or if someone have some experience :)

--- In firebird-support@yahoogroups.com, Thomas Steinmaurer <ts@...> wrote:
>
> > it's exactly the same for us :( it's garbage collection !
> >
> > when the garbage collection start, then any connection that try to load any row that are in the process of the garbage collection are blocked (freezed) ! in fact all the connection that try to select anything on the table are freeze ... this from several min, to sometime even hours !! of course it's a disaster :(
> >
> > for us the garbage collect start after we do a massive delete.
> >
> > to emulate it ... simple, delete severals thousands rows, and do a select AFTER this delete ... you will see that the select is block an ALL OTHER selects too :(
>
> Btw, with the Trace API, you can simply check out at statement-level, if
> a statement resulted in additional garbage collection work.
>
>
> --
> With regards,
> Thomas Steinmaurer (^TS^)
> Firebird Technology Evangelist
>
> http://www.upscene.com/
>
> Do you care about the future of Firebird? Join the Firebird Foundation:
> http://www.firebirdsql.org/en/firebird-foundation/
>
>
> > i m now thinging about mysql to solve this probleme (just to move our session table to mysql database), but i m not sure that mysql will not have the same probleme. anyone here can confirm ?
> >
> >
> >
> > --- In firebird-support@yahoogroups.com, "anthonyjang2012"<anthony@> wrote:
> >>
> >> We don't do anything particularly special in deletes / updates once a month. The last two times we have observed this issue, it occurred during a DB sweep so perhaps it is related to garbage collection. The strange thing is that everything is blocked, even other existing DB connections that all recover on their own after a few minutes.
> >>
> >> Regards,
> >> Anthony
> >>
> >>> Since this happen about once a month, do you happen to do massive monthly deletes or updates, Anthony, and do the blocking occur after such deletes/updates and before or during the next sweep? If so, a possible solution could (in some cases), be to delete/update a bit every hour or day rather than monthly.
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