PostgreSQL on Linux PC vs MacOS X

[Philippe Schmid]

Re: PostgreSQL on Linux PC vs MacOS X


[color=blue][color=green]
>> In my experience, a G4/1.25GHz computer with standard apple drive was
>> much
>> faster than the PC (Pentium 2+GHz, don't remember details) we tested
>> running
>> Linux. Both machines had plenty of RAM, same PostgreSQL settings,
>> etc. The PC
>> was much slower than the mac running backup/restore (more than 2x
>> slower). The
>> queries we tested were slower as well. Both machines had IDE drives.
>> I'd think
>> the Linux box could probably be made to be faster, but it had a long
>> way to go
>> to even match the G4.[/color]
>
> One possible explanation for your results would be that the Mac IDE
> drive lies about write completion while the PC IDE drive does not. You
> mention a backup/restore test, which is very write-intensive. Any
> system with an IDE drive that lies about write completion is going to
> blow away (write performance-wise) a system with an IDE drive that
> does not lie about it. Our tests last year were all with SELECT
> queries to prevent this factor from skewing our results. (Our app is
> read-heavy and we knew we would be getting a good hardware RAID setup
> that could handle the writes.)
>
> I do not have the same Apple hardware from a year ago to reproduce my
> tests. If I get time in the next week, I can try something on the
> same PC (RedHat 9, P3/800) vs. a G4/933, OS X Server 10.2.[/color]
I would say this test is not very meaningful as OS X Server 10.2 is
old, and...not as stable as one could hope, especially if used for
other services.
OS X Server 10.3 is better / much more stable (the "good enough"
depends on what you are doing with it).

Still, I would recommend using the standard OS X 10.3 on a separate box
and tune the kernel params for optimal Postgres use, this is if you
already have one spare Mac for that. Upgrading to the G5 will only be
really usefull if you have very CPU intensive queries. If you are
essentially i/o bound, than faster disks make more sense, and as
previously said, fast disks on a Mac require a third-party SCSI card
and an external RAID or an xRaid. Can be expensive or "cheap"
depending on the disk amount you need.

I would make some benchmarks...
hth,
Philippe
[color=blue]
>
>[color=green]
>> We have had excellent stability on both G4 and G5, MacOS 10.2.x and
>> 10.3.x,
>> PostgreSQL 7.3.x and 7.4.x. The only time we experienced instability
>> was just
>> after the G5 was released, the combination of G5, MacOS 10.2.7 and
>> PostgreSQL
>> 7.3.x just didn't work very well. Upgrading the G5 to MacOS 10.3.x
>> and
>> PostgreSQL 7.4.x brought back the stability we expected and we
>> haven't really
>> had any problems since.[/color]
>
> Our primary OS X 10.2 server crashed very frequently. Sometimes more
> than once per day. We changed machines and the crashes continued.
> Apple HW test on both boxes showed no problems. The vast majority of
> these crashes were under moderate load (~120 queries/min). A few
> times, reindexing would cause a crash without any other DB activity.
> With almost all of these crashes, there were no CrashReporter log
> entries. At that point, we felt like we had no recourse but to try
> something different (Linux/x86) and haven't looked back.
>
> - Jeff
>
> --
>
> Jeff Bohmer
> VisionLink, Inc.
> _______________ _______________ ___
> 303.402.0170 x121
> http://www.visionlink.org/
> _______________ _______________ ___
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[William Yu]

Re: PostgreSQL on Linux PC vs MacOS X

My guess is that you will get better performance from a similarly priced
Dual Opteron for the following reasons:

1) OS-X is not 64-bit yet, 64-bit Linux/BSD OS's are available
2) GCC is far better tuned for x86 than PowerPC/Itanium/etc
3) Postgres *seems* to prefer Opteron's ondie memory controller
architecture over shared bus -- especially in SMP configs

Is it enough of a difference? If you needed to eek out every possible %
performance because you have a critical production need, then the answer
is yes. Otherwise, it's easier to stick with the OS you know.


Jim Strickland wrote:[color=blue]
> Well, the whole reason I have asked this question is because my
> developer swears by OS X and PostgreSQL. However, I wanted opinions from
> other people who have possibly used a similar setup so I can make an
> informed decision. I will certainly keep your advice in mind. I guess
> the only reason I was asking about the version of OS X and the G5
> processor, is because that is all my developer uses and he seems to
> think they make a great combination, but that seems to be at odds with
> your experience.
>
> Perhaps some others will weigh in with their experiences and I will be
> able to make a sound decision. Fortunately there is no great rush to
> decide. Thanks for your help.[/color]

[Timothy Perrigo]

Re: PostgreSQL on Linux PC vs MacOS X

I've been working with PostgreSQL on OS X (G4, G5 and dual G5 systems)
for a few months now, and overall I've been really pleased; for us, it
seems to be a good match.

If you have both an OS X and a Linux or BSD system available, you could
run pgbench against both and get a rough idea on how they compare.


On Nov 4, 2004, at 1:33 PM, William Yu wrote:
[color=blue]
> My guess is that you will get better performance from a similarly
> priced Dual Opteron for the following reasons:
>
> 1) OS-X is not 64-bit yet, 64-bit Linux/BSD OS's are available
> 2) GCC is far better tuned for x86 than PowerPC/Itanium/etc
> 3) Postgres *seems* to prefer Opteron's ondie memory controller
> architecture over shared bus -- especially in SMP configs
>
> Is it enough of a difference? If you needed to eek out every possible
> % performance because you have a critical production need, then the
> answer is yes. Otherwise, it's easier to stick with the OS you know.
>
>
> Jim Strickland wrote:[color=green]
>> Well, the whole reason I have asked this question is because my
>> developer swears by OS X and PostgreSQL. However, I wanted opinions
>> from other people who have possibly used a similar setup so I can
>> make an informed decision. I will certainly keep your advice in mind.
>> I guess the only reason I was asking about the version of OS X and
>> the G5 processor, is because that is all my developer uses and he
>> seems to think they make a great combination, but that seems to be at
>> odds with your experience.
>> Perhaps some others will weigh in with their experiences and I will
>> be able to make a sound decision. Fortunately there is no great rush
>> to decide. Thanks for your help.[/color]
>
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