Deleting millions of rows every night

Niels Nes Niels.Nes at cwi.nl
Mon Jul 29 09:03:24 CEST 2013


On Mon, Jul 29, 2013 at 08:54:27AM +0200, Dennis Pallett wrote:
> Hello all,
> 
> We are going to be using MonetDB as a data mart between our data
> warehouse and our front-end applications and are planning to insert
> and delete several millions of rows from MonetDB every night as part
> of our data update cycle. We've noticed that MonetDB doesn't support
> the TRUNCATE statement so we're deleting all the data with DELETE
> FROM table. But is this the best way to delete millions of rows
> every night? Won't performance or free disk space degrade over time?

A 'DELETE ALL FROM table' is very similar to truncate and indeed will
cleanup all diskspace taken by the old rows.

A Delete with a where clause however, will leave data on disk behind.

Niels
> 
> Best regards,
> Dennis Pallett
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> users-list mailing list
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-- 
Niels Nes, Centrum Wiskunde & Informatica (CWI)
Science Park 123, 1098 XG Amsterdam, The Netherlands
room L3.14,  phone ++31 20 592-4098 	sip:4098 at sip.cwi.nl
url: http://www.cwi.nl/~niels   e-mail: Niels.Nes at cwi.nl
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