Re: How does TOAST compare to other databases' mechanisms?

Is all the info on using toast on the postgresql site, or is it somewhere
else?

Also, I'm assuming it is good for more than just test, correct?

Adam Lang
Systems Engineer
Rutgers Casualty Insurance Company
----- Original Message -----
From: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: "Frank Joerdens" <frank(at)joerdens(dot)de>
Cc: <pgsql-general(at)postgresql(dot)org>
Sent: Friday, October 06, 2000 5:47 PM
Subject: Re: [GENERAL] How does TOAST compare to other databases'
mechanisms?

> Frank Joerdens <frank(at)joerdens(dot)de> writes:
> > Can I go around bragging to my SQL-minded friends about using this
> > really cool thing that no other database has, or should I keep my mouth
> > shut because it's actually not so cool?
>
> IMHO it's pretty cool. You get the benefits of BLOB storage without
> having to deal with weird declarations or access methods. I have no
> idea whether any other databases do it the same way, but simply removing
> the limit on physical tuple length wouldn't have been as nice. See,
> with a toasted column, you don't pay to suck the contents of the column
> into memory when you read the row for a query that doesn't actually touch
> that column. So, for example, you might have a table declared like
>
> CREATE TABLE foo
> (key1 text,
> moddate timestamp,
> big_horking_data text);
>
> and you can do things like
>
> SELECT big_horking_data FROM foo
> WHERE key1 = 'bar' AND moddate > 'yesterday';
>
> Here the table is essentially acting as an index for the BLOB storage:
> the system won't bother to fetch the BLOB values for the rows that
> fail the WHERE check. You can't do that without lots of cruft in any
> non-TOAST-like scheme, AFAICS.
>
> regards, tom lane