From: Jonathan Mast [mailto:jhmast.develo...@gmail.com]
Sure we can argue about which DBMS has the fastest JOINs but
nonetheless it
remains that JOIN queries will always be computationally
expensive compared to single table queries.
Depends what you do with the results of those single table
Jonathan Mast wrote:
Perhaps the discussion should move back towards how Tomcat interacts with
databases.
It would be more on topic, but a well architected web application will
have a data access layer that is not dependent on the Servlet API, both
for testability and reusability. While a
Wareham cware...@visitlondon.com
To: Tomcat Users List users@tomcat.apache.org
Sent: Friday, 23 January, 2009 12:45:58 GMT +02:00 Athens, Beirut, Bucharest,
Istanbul
Subject: Re: PostgreSQL vs MySQL with Tomcat
Jonathan Mast wrote:
Perhaps the discussion should move back towards how Tomcat interacts
On Fri, Jan 23, 2009 at 11:45 AM, Chris Wareham
cware...@visitlondon.com wrote:
By it's very definition (see Codd or Date), an RDBMS should be capable
of performing joins with good performance. MySQL often struggles to do
so thanks to the poor optimiser, so you had to implement what should be
On Fri, Jan 23, 2009 at 6:23 AM, Leon Rosenberg
rosenberg.l...@googlemail.com wrote:
On Fri, Jan 23, 2009 at 11:45 AM, Chris Wareham
cware...@visitlondon.com wrote:
By it's very definition (see Codd or Date), an RDBMS should be capable
of performing joins with good performance. MySQL
Leon Rosenberg wrote:
On Fri, Jan 23, 2009 at 11:45 AM, Chris Wareham
cware...@visitlondon.com wrote:
By it's very definition (see Codd or Date), an RDBMS should be capable
of performing joins with good performance. MySQL often struggles to do
so thanks to the poor optimiser, so you had to
Leon, it's rare for me to disagree with you, but...
From: Leon Rosenberg [mailto:rosenberg.l...@googlemail.com]
For example if you need all orders by user with name Chris, you will
ALWAYS be faster if you first retrieve the userid, and than the orders
of the userid.
... I disagree and can
On Fri, Jan 23, 2009 at 12:36 PM, Chris Wareham
cware...@visitlondon.com wrote:
Leon Rosenberg wrote:
On Fri, Jan 23, 2009 at 11:45 AM, Chris Wareham
cware...@visitlondon.com wrote:
By it's very definition (see Codd or Date), an RDBMS should be capable
of performing joins with good
Leon Rosenberg wrote:
On Fri, Jan 23, 2009 at 12:36 PM, Chris Wareham
cware...@visitlondon.com wrote:
So you perform two queries from the application layer? You are basically
doing a join by hand - the cost of those two round trips to the database
will lose to a single query with a join,
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Chris,
Chris Wareham wrote:
I am particularly wary of MySQL because of the way missing features
have been disingenuously described as unnecessary, and broken
features as the MySQL developers knowing better than everyone else.
Not to pick a fight,
On Fri, Jan 23, 2009 at 12:59 PM, Chris Wareham
cware...@visitlondon.com wrote:
Reread my last message, and take a look at the internals of any half
decent RDBMS. Frequently accessed data will get cached in memory, and
the cost of many joins will be less than the cost of a hash table lookup
Christopher Schultz wrote:
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Chris,
Chris Wareham wrote:
I am particularly wary of MySQL because of the way missing features
have been disingenuously described as unnecessary, and broken
features as the MySQL developers knowing better than everyone
Leon Rosenberg wrote:
On Fri, Jan 23, 2009 at 12:59 PM, Chris Wareham
cware...@visitlondon.com wrote:
Reread my last message, and take a look at the internals of any half
decent RDBMS. Frequently accessed data will get cached in memory, and
the cost of many joins will be less than the cost of a
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Chris,
Chris Wareham wrote:
By the way, if it's not static data your caching,
how's your messaging system? Without one how are you going to maintain
the integrity of your caches? Even with one, can you tolerate a race
condition between the data
Perhaps I should explain more about how my rewrite sans JOINs works:
The reports read from a log table with this schema:
PK | ref_PK1 | ref_PK2 | ref_PK3 | start_time | stop_time
Where ref_PK# is the primary key of another table. These 3 other tables are
very shallow (row count 100). The log
As a general rule, it's been my experience with MySQL that well-designed
queries on properly indexed tables yield good performance. There are,
of course, exceptions to the rule where performance may be improved by
moving a portion of a query into the application and times when the
execution of a
Joseph Millet wrote:
Hi all,
in my opinion MySql as previously said is a lot easier to administrate, and
more developer friendly than postgre - even if its process managements is
far from being good (some single query may bring it down - as far as I could
see so far using 5.1.22 and many
When creating tables with referential integrity in MySQL you still get gems
like, e.g.:
mysql create table jimtest ( colA varchar(32) NOT NULL, CONSTRAINT fk1
FOREIGN KEY(colA) REFERENCES jimtest2(colA) ON DELETE CASCADE );
ERROR 1005 (HY000): Can't create table './test/jimtest.frm' (errno:
Perhaps the discussion should move back towards how Tomcat interacts with
databases.
This thread seems to be damning MySQL for not having super advanced
features, some of which should perhaps not even be in the purview of the
database layer, but more appropriately belong at the application layer
said, I've found it to be straightforward to install and administer. If
that contradicts your experience, then so be it. You're welcome to your
own opinion.
-Terence M. Bandoian
Subject:
Re: PostgreSQL vs MySQL with Tomcat
From:
Chris Wareham cware...@visitlondon.com
Date:
Tue, 20 Jan 2009 15
it to be straightforward to install and administer. If
that contradicts your experience, then so be it. You're welcome to your
own opinion.
-Terence M. Bandoian
Subject:
Re: PostgreSQL vs MySQL with Tomcat
From:
Chris Wareham cware...@visitlondon.com
Date:
Tue, 20 Jan 2009 15:53:05 +
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Rusty,
Rusty Wright wrote:
I think the biggest gripe I've had with mysql is the problem where I was
violating a unique constraint and it was giving me some generic
(completely useless) error; HY001 I think.
I've always found the error messages
Wow, this almost reads like a direct quote from MySQL marketing
literature. Like marketing literature, it's not necessarily untruthful,
but it does describe things selectively.
Terence M. Bandoian wrote:
I don't have a great deal of experience with Postgres but I have been
using MySQL since the
, Beirut, Bucharest,
Istanbul
Subject: Re: PostgreSQL vs MySQL with Tomcat
It's a rewrite of an app I did awhile ago in php.
I think the biggest gripe I've had with mysql is the problem where I was
violating a unique constraint and it was giving me some generic (completely
useless) error; HY001 I
In our company we used MySQL and Postgres for several projects. Both
DBMSs are mature and stable, and they are used worldwide for large-scale
projects. Performance-wise we measured some differences, but they were
not so big to notice them in the real-life loads. In other words, having
some
the only really major difference I can think of is T-SQL stored procedures,
which have no counterpart in Postgres.
PostgreSQL does have support for stored procedures, you can even
choose from 4 languages out of the box and 3 more from addons:
http://www.postgresql.org/download/products/4.html.
Users List users@tomcat.apache.org
Sent: Monday, 19 January, 2009 13:24:54 GMT +02:00 Athens, Beirut, Bucharest,
Istanbul
Subject: Re: PostgreSQL vs MySQL with Tomcat
the only really major difference I can think of is T-SQL stored procedures,
which have no counterpart in Postgres.
PostgreSQL
I don't have a great deal of experience with Postgres but I have been
using MySQL since the days of mSQL and have found it to be fast,
reliable, easy to install on both Linux and Windows and straightforward
to administer. It provides good support for the ANSI standard and the
documentation is
I stopped using MySQL when it was at version 4 because the transactional
locking table (InnoDB) had different licensing restrictions than the
rest of MySql (I'm not sure if this is true any longer.)
We switched to Postgresql (of comparable price!) and basically found it
well-documented,
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Rusty,
Rusty Wright wrote:
I'm in the process of migrating a MySQL database to PostgrSQL.
Is this to cool-off your DBA's ears? ;)
Seriously, if you could explain why you've decided to switch, I think it
would help a lot of readers understand some
It's a rewrite of an app I did awhile ago in php.
I think the biggest gripe I've had with mysql is the problem where I was
violating a unique constraint and it was giving me some generic (completely
useless) error; HY001 I think.
In various ways, which I can't articulate, MySQL just feels to
Some comments (and answers to Christopher and Rusty) on PostgreSQL:
In 2004 our team decided to use PostgreSQL instead of the well-known
MySQL (current version 4). The main reasons where
- real referential integrity
- real transactions
- support for UTF-8 enoding
- better compliance with the SQL
Ken Bowen wrote:
Hi all (especially Chris -- very informative long post today on
Tomcat/MySQL):
For a several reasons (including the apparent infinite default for
connection timeout), I'm contemplating switching one or two projects
from MySQL to PostgreSQL. I'd like to gather opinions on
That may be true about the public schema being used when one isn't specified.
But when I use their pgAdmin gui tool and open the query window and try to run
the tiger sample from the Jailer tutorial it blows up on the table creates,
saying:
ERROR: no schema has been selected to create in
As far as schemas in Postgres go, a normal way to handle them is to create
schema-specific users with an appropriately-set default schema, e.g.
something like:
CREATE SCHEMA company_a ;
CREATE USER company_a_user PASSWORD 'foo' ;
ALTER USER company_a_user SET search_path TO company_a, public
Regarding MySQL's autoincrement type, it looks like PostgreSQL has something
similar:
http://www.postgresql.org/docs/8.3/interactive/datatype-numeric.html#DATATYPE-SERIAL
I'm in the process of migrating a MySQL database to PostgrSQL.
Christopher Schultz wrote:
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Our organization has products backed by both databases and we are almost
entirely shielded from the database details in Tomcat. I don't really see
how it should matter in terms of Tomcat (or any Web container). I'm
thinking this is more a Java issue than a Tomcat issue.
The main differences
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Ken,
Ken Bowen wrote:
Unfortunately, MySQL isn't really that tunable. On the other hand, MySQL
requires very little in the way of tuning!
This was my comment, and that's the gist I got from reading Zawodny's
and Balling's High Performance MySQL
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Jonathan,
Jonathan Mast wrote:
* Postgre has more features (sequences and triggers) but also an enormous
amount of complexity
* MySQL has much finer authorization control, but lacks some of the big-boy
features such as triggers
** of course a
I've found MySQL's error messages particularly worthless in some situations; I
had a foreign constraint and it was giving me some generic error when I was
violating that foreign constraint. Say MySQL around our DBA and steam starts
coming out of his ears.
The one warning I can think of with
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