[Kolab-devel] Re: OpenLDAP performance issues

[Bernhard Reiter]

Hi Martin,

On Thursday 26 May 2005 00:41, Martin Konold wrote:

> I just did an experiment:
>
> kepler:/kolab/RPM/SRC/openldap/openldap-2.2.23 # ./configure ; make depend
> ; make
> kepler:/kolab/RPM/SRC/openldap/openldap-2.2.23 # ldd servers/slapd/slapd
>         linux-gate.so.1 =>  (0xffffe000)
>         libdb-4.3.so => /usr/lib/tls/libdb-4.3.so (0x40019000)

BTW: Why are you using libdb-4.3 here?
I thought that Dieter, the Debian people and others recomend to use libdb-4.2.

>         libresolv.so.2 => /lib/libresolv.so.2 (0x400ff000)
>         libpthread.so.0 => /lib/tls/libpthread.so.0 (0x40112000)
>         libc.so.6 => /lib/tls/libc.so.6 (0x40124000)
>         /lib/ld-linux.so.2 (0x40000000)
> kepler:/kolab/RPM/SRC/openldap/openldap-2.2.23 # LD_ASSUME_KERNEL=2.4.30
> ldd servers/slapd/slapd
>         linux-gate.so.1 =>  (0xffffe000)
>         libdb-4.3.so => /usr/lib/libdb-4.3.so (0x40019000)
>         libresolv.so.2 => /lib/libresolv.so.2 (0x400ff000)
>         libpthread.so.0 => /lib/i686/libpthread.so.0 (0x40112000)
>         libc.so.6 => /lib/i686/libc.so.6 (0x40164000)
>         /lib/ld-linux.so.2 (0x40000000)
>
> So the OpenLDAP 2.2.23 package is normally using the glibc libpthread if
> not prevented by the "--with-threads=pth" switch.
>
> I therefore assume that it is a good idea to also build with the OS/system
> provided  thread implementation as most developers and users don't use the
> GNU pth library.

I don't know enough about this thread library to have an opinion yet,
but we should ask the openpkg people about this.

> Bernhard: Do you remember when I mentioned the LD_ASSUME_KERNEL environment
> variable at the "Mailserver Konferenz" in Magdeburg last week?

Of course, as you can see from the issue707, I also entered it there
as result of our chat.
Steffen replied though, that this did not make a difference for him.

> Check how the simple setting of this environment variable changes the
> behavior of the dynamic linker. Many applications are known to be sensitive
> with regards to the use of NPTL. I therefore assume that OpenLDAP/bdb is
> also sensitive to the choice of thread library implementation.

This is certainly an area where we have to look closer.

> Steffen: I propose to remove "--with-threads=pth" as a first step.

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