Thread: Transactional vs. Read-only (Retrieval) database

Le Jeudi 11 Avril 2002 15:14, Samuel J. Sutjiono a écrit :
> I'd like to get some opinions if there are any benefits (i.e. in terms of
> performance) of creating two separate databases, one for transactions
> (insert, update, delete) and the other one is for retrieval/search
> (select).

Dear Samuel,

You do not need to create two separate databases. It is possible to write
server-side code to copy static data (read-only) to other tables. This can be
done using triggers and/or cron jobs.

A more sopisticated solution would be to store LEFT JOIN query results in the
original table using triggers. For example : you have tables COMPANY and
EMPLOYEE. Instead of running a LEFT JOIN on EMPLOYEE->COMPANY, it is possible
to store COMPANY name in table employee using a trigger.

Then, you don't need LEFT JOINS any more, simple SELECTs are enough, which is
fantastic for heavy loaded databases.

Same as for many operations. Try the EXPLAIN clause on a query. If too heavy,
try to write some code to simplify the query using triggers...

PostgreSQL is the most advanced open-source database available today. It has
several server-side languages (plpgsql, plperl, plpython). Maybe you should
try plpgsql which is easy to learn.

Well-optimized, PostgreSQL can run 10 times faster than well-known open-source
databases. If you need to test server-side programming, do not hesitate to
download and install pgAdmin2 (http://pgadmin.postgresql.org), PostgreSQL
Windows GUI.

Cheers,
Jean-Michel

Sam,

> I'd like to get some opinions if there are any benefits (i.e. in
> terms of performance) of creating two separate databases, one for
> transactions (insert, update, delete) and the other one is for
> retrieval/search (select).

No.  Not in Postgresql, unless you wanted to get really exotic.  Also,
keep in mind that you cannot join tables from seperate databases in
postgresql.

There are *lots* of performance advantages to be had by managing disk
access and memory carefully. But not through seperate databases.

-Josh Berkus