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Thread: RE: pre-beta is slow

RE: pre-beta is slow

From
"Mikheev, Vadim"
Date:
> recently  I  have downloaded a pre-beta postgresql,  I found  
> insert and update speed is slower then 7.0.3,
> even I turn of sync flag,  it is still slow than 7.0, why? 
> how can I make it faster?

Try to compare 7.0.3 & 7.1beta in multi-user environment.

Vadim

Re: pre-beta is slow

From
Hannu Krosing
Date:
"Mikheev, Vadim" wrote:
> 
> > recently  I  have downloaded a pre-beta postgresql,  I found
> > insert and update speed is slower then 7.0.3,
> > even I turn of sync flag,  it is still slow than 7.0, why?

How much slower do you see it to be ?

> > how can I make it faster?
>
> Try to compare 7.0.3 & 7.1beta in multi-user environment.

As I understand it you claim it to be faster in multi-user environment ?

Could you give some brief technical background why is it so 
and why must it make single-user slower ?

---------------
Hannu

RE: pre-beta is slow

From
"Mikheev, Vadim"
Date:
> > Try to compare 7.0.3 & 7.1beta in multi-user environment.
> 
> As I understand it you claim it to be faster in multi-user 
> environment ?
> 
> Could you give some brief technical background why is it so 
> and why must it make single-user slower ?

Because of commit in 7.1 does fsync, with ot without -F
(we can discuss and change this), but in multi-user env
a number of commits can be made with single fsync.
Seems I've described this before?

Vadim

Re: pre-beta is slow

From
Tom Lane
Date:
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM> writes:
> Because of commit in 7.1 does fsync, with ot without -F
> (we can discuss and change this), but in multi-user env
> a number of commits can be made with single fsync.

I was planning to ask why you disabled the -F switch.  Seems to me that
people who trusted their OS+hardware before would still want to do so
in 7.1, and so it still makes sense to be able to suppress the fsync
calls.
        regards, tom lane

RE: pre-beta is slow

From
"Mikheev, Vadim"
Date:
> > Because of commit in 7.1 does fsync, with ot without -F
> > (we can discuss and change this), but in multi-user env
> > a number of commits can be made with single fsync.
> 
> I was planning to ask why you disabled the -F switch. Seems 
> to me that people who trusted their OS+hardware before would
> still want to do so in 7.1, and so it still makes sense to be
> able to suppress the fsync calls.

I just didn't care about -F functionality, sorry.
I agreed that we should resurrect it.

Vadim

RE: pre-beta is slow

From
"Mikheev, Vadim"
Date:
> > > Try to compare 7.0.3 & 7.1beta in multi-user environment.
> > 
> > As I understand it you claim it to be faster in multi-user 
> > environment ?
> > 
> > Could you give some brief technical background why is it so 
> > and why must it make single-user slower ?
> 
> Because of commit in 7.1 does fsync, with ot without -F
> (we can discuss and change this), but in multi-user env
> a number of commits can be made with single fsync.
> Seems I've described this before?

Ops, I forgot to answer question "why in single-user env 7.1 is
slower than 7.0.3?". I assumed that 7.1 was compared with 7.0.3
*with -F*, which probably is not correct, I don't know.
Well, the next test shows that 7.1 is faster in single-user env
than 7.0.3 *without -F*:

table (i int, t text); 1000 INSERTs (in separate transactions),
sizeof(t) 1 .. 256:

7.0.3: 42 sec -> 24 tps
7.1  : 24 sec -> 42 tps

Vadim

RE: pre-beta is slow

From
"Mikheev, Vadim"
Date:
> > I just didn't care about -F functionality, sorry.
> > I agreed that we should resurrect it.
> 
> OK.  Do you want to work on that, or shall I?

In near future I'll be busy doing CRC + "physical log"
things...

Vadim

Re: pre-beta is slow

From
Tom Lane
Date:
"Mikheev, Vadim" <vmikheev@SECTORBASE.COM> writes:
> I just didn't care about -F functionality, sorry.
> I agreed that we should resurrect it.

OK.  Do you want to work on that, or shall I?
        regards, tom lane