what if native systemd service is slower than old sysvinit script?
mzerqung at 0pointer.de
Thu Sep 15 03:48:45 UTC 2011
On Wed, 14.09.11 01:03, Michał Piotrowski (mkkp4x4 at gmail.com) wrote:
> 2011/9/13 Tom Lane <tgl at redhat.com>:
> > (This isn't new with 9.1, btw --- the last version or so of 9.0
> > for F16 was the same, since we switched over to native systemd
> > files.)
> I used this service file on F15 and it starts slower
> 4214ms postgresql.service
> if we compare with an old SysVinit script
> 2469ms postgresql.service
> So I wonder if it makes sense to convert in such case?
> (I know that it is not about boot speed, it can start slower if needed.)
I am currently travelling, so I don't have the peace to fully read and
reply to this thread, but let me clear up a few things:
a) don't misunderstand systemd-analyze, the times reported by it are
wallclock times, and hence parallelization increases these values since
the jobs are influenced by others (while decreasing the overall
time). the values are interesting in comparison to other values from the
same boot, but even then need to be read with a grain of salt.
b) systemd doesn't really do anything that was computation
intensive. so there's no real reason for the slowdown, and definitely
fixable. I am not sure what pgsql is doing there on startup... might be
something on those scripts, not necessarily systemd at fault. As long as
this is a problem for pg only and nothing else this is a strong
indication for this.
Either way, I don't want to point fingers, and I don't really know
what's going on, but what I actually do know is that the currently
available measurement data is not useful, we need to investigate this
further and then figure out what's really going on and where there's
something to fix. I'll look into this in detail next week.
Lennart Poettering - Red Hat, Inc.
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