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!! 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.

./heLen