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DB benchmark and pg config file help

From: Kevin Hunter <hunteke(at)earlham(dot)edu>
To: PostgreSQL Performance List <pgsql-performance(at)postgresql(dot)org>
Subject: DB benchmark and pg config file help
Date: 2007-01-17 22:15:24
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
Hello List,

Not sure to which list I should post (gray lines, and all that), so 
point me in the right direction if'n it's a problem.

I am in the process of learning some of the art/science of benchmarking. 
  Given novnov's recent post about the comparison of MS SQL vs 
PostgresQL, I felt it time to do a benchmark comparison of sorts for 
myself . . . more for me and the benchmark learning process than the 
DB's, but I'm interested in DB's in general, so it's a good fit.  (If I 
find anything interesting/new, I will of course share the results.)

Given that, I don't know what I'm doing.  :|  It seems initially that to 
do it properly, I have to pick some sort of focus.  In other words, 
shall I benchmark from a standpoint of ACID compliance?  Shall I 
benchmark with functionality in mind?  Ease of use/setup?  Speed?  The 
latter seems to be done most widely/often, so I suspect it's the easiest 
standpoint from which to work.  Thus, for my initial foray into 
benchmarking, I'll probably start there.  (Unless of course, in any of 
your wisdom, you can point me in a better direction.)

 From my less-than-one-month-of-Postgres-list-lurking, I think I need to 
be aware of at /least/ these items for my benchmarks (in no particular 

* overall speed (obvious)

* mitigating factors
   - DB fits entirely in memory or not (page faults)
   - DB size
   - DB versions

* DB non-SELECT performance.  A common point I see in comparisons of
   MySQL and PostgresQL is that MySQL is much faster.  However, I rarely
   see anything other than comparison of SELECT.

* Query complexity (e.g. criteria, {,inner,outer}-joins)
    ex.	SELECT * FROM aTable; vs
	  FUNC( var ),
	     x IN (<list>)
	  AND b ...

* Queries against tables/columns of varying data types.  (BOOLEAN,

* Queries against tables with/out constraints

* Queries against tables with/out triggers {post,pre}-{non,}SELECT

* Transactions

* Individual and common functions (common use, not necessarily common

* Performance under load (e.g. 1, 10, 100 concurrent users),
   - need to delineate how DB's handle concurrent queries against the
     same tuples AND against different tuples/tables.

* Access method (e.g. Thru C libs, via PHP/Postgres libs, apache/web,
   command line and stdin scripts)

# I don't currently have access to a RAID setup, so this will all have
   to be on single hard drive for now.  Perhaps later I can procure more
   hardware/situations with which to test.

Clearly, this is only a small portion of what I should be aware when I'm 
benchmarking different DB's in terms of speed/performance, and already 
it's feeling daunting.  Feel free to add any/all items about which I'm 
not thinking.

The other thing: as I'm still a bit of a noob, all my use of the 
Postgres DB has been -- for the most part -- with the stock 
configuration.  Since I'm planning to run these tests on the same 
hardware, I can pseudo-rule out hardware-related differences in the 
results.  However, I'm hoping that I can give my stats/assumptions to 
the list and someone would give me a configuration file that would /most 
likely/ be best?  I can search the documentation/archives, but I'm 
hoping to get head start and tweak from there.

Any and all advice would be /much/ appreciated!



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Subject: Re: Monitoring Transaction Log size
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Subject: Re: Configuration Advice

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