Re: scalablility problem

From: Tom Lane
Subject: Re: scalablility problem
Date: ,
Msg-id: 6434.1175358708@sss.pgh.pa.us
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In response to: Re: scalablility problem  ("Joshua D. Drake")
Responses: Re: scalablility problem  (Xiaoning Ding <-state.edu>)
List: pgsql-performance

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scalablility problem  (Xiaoning Ding <-state.edu>, )
 Re: scalablility problem  ("Dave Dutcher", )
 Re: scalablility problem  (Tom Lane, )
  Re: scalablility problem  (Xiaoning Ding <-state.edu>, )
   Re: scalablility problem  (Scott Marlowe, )
   Re: scalablility problem  (Ron Mayer, )
    Re: scalablility problem  (Xiaoning Ding <-state.edu>, )
     Re: scalablility problem  (Dave Cramer, )
 Re: scalablility problem  (Scott Marlowe, )
  Re: scalablility problem  (Xiaoning Ding <-state.edu>, )
   Re: scalablility problem  ("Joshua D. Drake", )
    Re: scalablility problem  (Tom Lane, )
     Re: scalablility problem  (Xiaoning Ding <-state.edu>, )
 Re: scalablility problem  (Christopher Browne, )
  Re: scalablility problem  (Guido Neitzer, )
   Re: scalablility problem  (Michael Stone, )
    Re: scalablility problem  (Xiaoning Ding <-state.edu>, )
  Re: scalablility problem  (Xiaoning Ding <-state.edu>, )

"Joshua D. Drake" <> writes:
>> I use RHEL 4. I can not understand how the scalability related with
>> shared memory?

> It isn't RHEL4 and shared memory. It is PostgreSQL and shared memory.
> Things have changed with PostgreSQL since 7.3 (7.3 is really god awful
> old) that allow it to more effectively access shared memory and thus
> provide better performance.

Some specifics:

* bufmgr algorithms redesigned to allow larger number of shared buffers
to be used effectively

* bufmgr redesigned to not have a single lock for management of all
shared buffers; likewise for lockmgr

* lots of marginal tweaks such as paying attention to cache line
alignment of "hot" shared data structures

I'm probably forgetting some things but I think the bufmgr and lockmgr
changes were the biggest improvements in this area.

            regards, tom lane


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From: Xiaoning Ding
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