Re: How long - Vacumm full - 10 million to 90,000 - Mailing list pgsql-sql

From Steve Crawford
Subject Re: How long - Vacumm full - 10 million to 90,000
Date
Msg-id 483EDD5B.3030608@pinpointresearch.com
Whole thread Raw
In response to How long - Vacumm full - 10 million to 90,000  (Emi Lu <emilu@encs.concordia.ca>)
List pgsql-sql
Emi Lu wrote:
> ...
> I have a table from around 10 million to 90,000, after deletion, I 
> tried to use vacuum full, but it seems that it takes forever to 
> finish. Could anyone tell me how long it will take to finish the 
> Recovering disk space please?
No. Probably a looooonnnnnng time.

In a case like this where you are retaining less than 1% of your records 
you are likely to see far, far faster results using CLUSTER - with the 
added advantage that CLUSTER will create fresh indexes for you, too.

Alternately, you can:
CREATE TABLE xxx as SELECT * from yourtable;
TRUNCATE yourtable;
INSERT into yourtable SELECT * from xxx;
DROP TABLE xxx;

If you are so close to out-of-space on your disk that you don't have the 
room those 90,000 records will require, you may have to dump/restore 
using another machine.

Cheers,
Steve


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