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Re: why the DB file size does not reduce when 'delete'the data in DB?

From: "Mitch Vincent" <mitch(at)venux(dot)net>
To: "xuyifeng" <jamexu(at)telekbird(dot)com(dot)cn>, "Roberto Mello" <rmello(at)cc(dot)usu(dot)edu>
Cc: <pgsql-hackers(at)postgreSQL(dot)org>
Subject: Re: why the DB file size does not reduce when 'delete'the data in DB?
Date: 2001-03-04 18:37:11
Message-ID: 00d501c0a4da$21a45ee0$0200000a@windows (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-sql
> I know your situations,  your DB is not updated and inserted lots of
records in few minutes,
> mine is difference,  I have a real time Stock Trading  system, you know,
stock, its price
> is changed every minute or even every second ,  I need update and insert
delta change into DB,
> draw their trend graphics,  suppose there are 3000 stocks in market,
there maybe 9000 records
> changed and inserted in one minutes, because PGSQL's storage manager
problem( it does not
> reuse deleted record space),  in 4 hours trading period,  my harddisk can
be full filled.  because in
> the period, the table indeed gets very large, doing VACCUME is impossible
in realtime, it will lock
> out other clients too long time,  my point of view is PGSQL is fit for
static or small changed database,
> not fit for lots of change in short time.

It's admitadly a problem so I don't think you need to convince everyone that
it's not the best way to handle things :-)

I hate to say it, but your options currently are to upgrade your storage
device or change databases... I think I'd fork out some cash for some new
hardware verses buying a commercial database or putting up with the missing
features of MySQL..

All my humble opinion of course, I wish you the best of luck.

-Mitch


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