| From: | Francisco Reyes <lists(at)stringsutils(dot)com> | 
|---|---|
| To: | l(dot)rame(at)griensu(dot)com | 
| Cc: | pgsql-general(at)postgresql(dot)org | 
| Subject: | Re: Database size | 
| Date: | 2010-01-11 18:42:22 | 
| Message-ID: | cone.1263235342.384926.30109.1000@shelca | 
| Views: | Whole Thread | Raw Message | Download mbox | Resend email | 
| Thread: | |
| Lists: | pgsql-general | 
Leonardo M. Ramé writes:
> A customer of mine asked me to periodically delete old, unneeded records
> containing ByteA fields, because he think it will reduce the database
> size on disk. Is this true?.
No.
> For example, in Firebird, the database size
> is not reduced until you do a Backup-Restore of the database.
Not sure about ByteA, but in general... in potgres you need to do that or a 
vacuum full.. or copy all the data of the table into a new table and rename.
Having said that.. if you delete old rows and do a vacuum and/or have 
autovacuum enabled the  space of those old rows can be re-used, slowing down 
the growth of the table. So yes, deleting old rows and doing a vacuum is a 
good thing.. but no I don't believe it will reduce database size.
I say "don't believe" because I don't recall if byteA was stored in the 
table itself or was stored outside using TOAST.. so I am not sure about 
how/when space is released for it.
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