Re: 9.3.5 failing to compile with dtrace on FreeBSD 10.1

Just wanted to thank Lacey for the assistance. I set up my first BSD server
recently and installing things via ports had been going great until this.
The docs don't mention how to enable the kernel modules permanently either,
so thanks also for that additional note.
https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/dtrace-enable.html

Perhaps adding a section on BSD ports and/or expanding on the Dtrace
section (15.7.6.6) in this part of the postgresql install docs may be
helpful for others?
http://www.postgresql.org/docs/current/static/installation-platform-notes.html

None of the other steps besides the kernel loading are needed for
compilation and installation, but could be handy.

--
Keith Fiske
Database Administrator
OmniTI Computer Consulting, Inc.
http://www.keithf4.com

On Mon, Dec 22, 2014 at 2:22 PM, Lacey Powers <lacey(dot)leanne(at)gmail(dot)com>
wrote:

> Hello Luca,
>
> I had some success getting PostgreSQL 9.4 to build on FreeBSD 10.1-p2
> RELEASE with DTrace. The probes look fully functional, and fun to work
> with, though I haven't had time to get incredibly deep into using them.This
> is what worked for me, after much digging around.
>
> I was building and running PostgreSQL and dtrace directly on my
> workstation, not in a jail. I'm not sure what additional hoops would need
> to hopped through off-hand to run dtrace on FreeBSD in a jail.
>
> Initially, I got compile errors, but I tracked those down and realized
> that I needed to load the dtrace kernel modules, which I had expected to be
> loaded automatically, but weren't. Otherwise, you get cryptic compile
> errors.
>
> I had to load the dtrace kernel modules with:
>
> kldload dtraceall (and enable it in /boot/loader.conf with
> dtraceall_load="YES", if you want it to hang around)
>
> Add the following lines to your /etc/make.conf (because detailed
> backtraces are helpful)
>
> STRIP=
> CFLAGS+=-fno-omit-frame-pointer
>
> Once that's loaded, change the permissions to 0666 on /dev/dtrace/helper
> (and add that to /etc/devfs.conf with "perm /dev/dtrace/helper 0666" if you
> want it to persist)
>
> Though be aware that there are security implications for that, since other
> users could make a ton of probes and exhaust kernel memory. Alternately,
> you could add pgsql to wheel, since root and wheel are the owner and group
> for that devfs node.
>
> Also be sure to not use devel/libelf from ports, because that doesn't seem
> to play nice with dtrace, and keeps probes from registering.
>
> After doing all that, I could get dtrace to build, link, and register
> userland probes with the database/postgresql94-server and
> database/postgresql94-client, and successfully count transaction times in a
> dtrace script.
>
> One final note, the freebsd-dtrace(at)freebsd(dot)org list, is very helpful with
> esoteric DTrace issues.
>
> I hope this all helps. =)
>
> Regards,
>
> Lacey
>
>
>
> On Tue, Dec 16, 2014 at 4:06 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>>
>>> If you want to push on this I think you'll need to find a BSD dtrace
>>> expert. You shouldn't need to show him/her much except the above
>>> dtrace invocation and the probes.d file.
>>>
>>> I've filled a bug report and I'll report back here if I get any update
>> on the matter.
>> In the meantime I've tried 9.4 beta and the same issue arises.
>>
>> Luca
>>
>>
>>
>
>
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