[KLUG Members] MySQL -vs- Postgresql - speed.

[Bruce Smith]

A friend of mine (not on this list) has been playing with databases.
Influenced by certain people on this list, I recommended Postgresql.

He wasn't happy with the performance and compared it to MySQL.
This is a quote from an email he sent me:

> Straight out of the box MySQL inserted the 20,000 records
> into the database via a PERL script in 10 hours.
> Postgresql took 40 hours!  Yikes!!
> BTW... this is on a Dual P-III 800 Mhz CPU's w/2 GB of RAM
> and a 3ware controller running two IBM 60'GB's IDE's in RAID-1.

I've read that Postgresql may be a little slower than MySQL, but 
that's not "a little slower", that's a LOT SLOWER!

>From Adam's performance tuning presentation, I recommended he start
Postgresql with "-F" and a larger "-B".  (he hasn't reported his
findings on that yet)  Is there anything else he can do to improve 
Postgresql performance???  

Also, a question came up about Postgresql's "vacuum".  From the docs:

"VACUUM reclaims storage occupied by deleted tuples. In normal
PostgreSQL operation, tuples that are DELETED or obsoleted by UPDATE are
not physically removed from their table; they remain present until a
VACUUM is done. Therefore it's necessary to do VACUUM  periodically,
especially on frequently-updated tables."

Does that mean _ALL_ updates to a row cause a deleted tuple?
Or only updates that meet a certain condition, like changing a 
primary key (or something)?

--------------------------------------------
Bruce Smith                bruce@armintl.com
System Administrator / Network Administrator
Armstrong International, Inc.
Three Rivers, Michigan  49093  USA
http://www.armstrong-intl.com/
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