Message-ID: <408E825C.10209@cs.msu.su>
Date: Tue, 27 Apr 2004 19:55:08 +0400
From: Alexey Borzov <borz_off@cs.msu.su>
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To: Tim Conrad <tim@timconrad.org>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>,
	PostgreSQL advocacy <pgsql-advocacy@postgresql.org>
Subject: Re: [HACKERS] What can we learn from MySQL?
References: <200404262213.44601.jm@poure.com>
	<200404262041.i3QKfZs28845@candle.pha.pa.us>
	<20040427152753.GA34713@external.timconrad.org>
In-Reply-To: <20040427152753.GA34713@external.timconrad.org>
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Hi!

Tim Conrad wrote:
> I was researching an article I wrote about a comparison between
> Postgres and MySQL recently (If you want, you can read the article
> at http://www.devx.com/dbzone/Article/20743/). I noticed some clear
> differences between the mysql.com website and the Postgres website.

Sorry, couldn't resist: may I suggest doing the research *before* 
writing an article, not *after*?

My favourite part of it is:
--------
MySQL uses traditional row-level locking. PostgreSQL uses something 
called Multi Version Concurrency Control (MVCC) by default. MVCC is a 
little different from row-level locking in that transactions on the 
database are performed on a snapshot of the data and then serialized. 
New versions of PostgreSQL support standard row-level locking as an 
option, but MVCC is the preferred method.
--------

> 2) There doesn't seem to be a clear roadmap on Postgres features.
>    When certian things are expected. There's the TODO list that
>    Bruce maintains, but it only outlines 'near' fixes. MySQL has a
>    nice listing of what to expect in certian future versions. I know
>    it's not a perfect list, but it'd be nice to know when full blown
>    replication will be included in PostgreSQL as an example.

MySQL's roadmap is complete bullshit. Subselects were first promised in 
4.0, which was "not that far away" [1] back in 1998! Well, they are in 
4.1, which is still alpha in 2004.

Of course, some gullible people actually believe this and compare [2] 
the existing and working implementations with vaporware (MySQL 5.1, 
anyone?).

>    On those same lines, there doesn't seem to be anything about the
>    improvements in the minor versions. It seems that in every
>    release (i.e. 7.2,7.3,7.4) there are pretty significant changes,
>    but finding a place that outlines these changes is somewhat
>    difficult. 

Have you tried looking in the release notes [3]?


[1] http://www.geocrawler.com/archives/3/194/1998/8/0/1061364/
[2] http://www.devx.com/dbzone/Article/20743/1763?supportItem=1
[3] http://www.postgresql.org/docs/7.4/interactive/release.html