Subject Re: [firebird-support] Please help! Database stops responding after all users have been connected.
Author Helen Borrie
At 04:26 PM 10/09/2004 +0300, you wrote:

>Helen Borrie wrote:
> >At 03:16 PM 10/09/2004 +0300, you wrote:
> >
> >
> >>Hi, all
> >>
> >>I have a production system runs with firebird about 3 years. About week
> >>ago the system's behaviour becamed very strange. Server almost stops
> >>responding after N-th user have connected to the database. Suddenly
> >>simple queries becames too heavy - execution time raises from
> >>milliseconds to minutes. When it happens CPU load is extreme high on
> >>first hardware and moderate on second (hardware configurations are
> >>described below), system memory is not exhausted and HDD activity is low.
> >>
> >>I've tried to check the database, backup/restore, upgrade Firebird from
> >>1.5.0 to 1.5.1, switch from super to classic and back, migration to
> >>another hardware - nothing helps. A few days ago server works before
> >>hang about 3-4 hours. Now it takes a few minutes.
> >>
> >>The system serves about 15-25 connections. The database size is about
> >>350-400Mb, last year added about 100Mb.
> >>
> >>Hardware: AMD Athlon XP3200+, 1.5Gb RAM, DPT Ultra-80 SCSI RAID 0 (3 x
> >>9.1Gb HDD) + one standalone SCSI HDD for system boot, gigabit ethernet
> >>controller, OS - Red Hat Linux 9.0 . I've tried another computer: Dual
> >>Xeon 2.8 GHz, 2Gb RAM, 18Gb U160 SCSI HDD (10000RPM), gigabit ethernet
> >>controller, OS - Fedora Core 1.
> >>
> >>I suspect the following:
> >>- the production database and security.fdb are descendants from beta
> >>versions of Firebird 1.5 or even release 1.0 . But backup/restore of it
> >>was not helped and ODS version is 10.1 now.
> >>- My old, but simple UDFs stops working, but how they did work about 3
> >>last years? And there are no server crashes. By the way it worked on the
> >>same system at least from 1.5.0 release date (April or May)
> >>- some fundamental OS limits have been reached.
> >>
> >>And now the strangest thing: I've just replaced the HDD in the dual Xeon
> >>system and installed the Firebird under W2003 Server there (affinity
> >>mask was set to 15 in firebird.conf). The system is working excellent
> >>under load already 4 hours.
> >>
> >>Please help me to diagnose and solve the problem.
> >>
> >>
> >
> >Clearly you didn't have Red Hat 9.1 or Fedora Core 1 for the past three
> >years!!
> >
>Sure, but at least from RH9 release date. I've migrated from RH 7.2.
>Fedora 1 was installed yesterday on fresh hardware.
> > Best guess here is that NPTL threading is messing things up. See
> >the Linux installation notes in the Firebird 1.5 release notes for
> >instructions on disabling the NTPTL; or install the NPTL kit for Firebird.
> >
> >
>And how about the same problem with Super 1.5.0 and Classic 1.5.1 ?

Sorry, I don't understand precisely what you are asking. But Superserver
spawns a thread for each user process and for other processes, such as
garbage collection; whereas Classic creates a unique process for each if you run the non-NPTL SS on a Linux that uses NPTL, then
the creation of user processes is going to fall over.

I really don't know whether NPTL raises issues for Classic at all. But,
given that there is no NPTL kit for Classic, one can suppose not...