Re: TOAST behavior in 8.3 and 8.4

Lewis Kapell wrote:
> I have a table with a text column, wherein most values range between
> 800 and 1700 bytes. The data should be highly compressible, however
> these values appear to be too small to trigger the TOAST mechanism -
> I understand the default value of TOAST_TUPLE_THRESHOLD is about
> 2kb.

> However, I checked to see whether the behavior of TOAST had been
> changed in 8.4, since I am hoping to upgrade soon. I found the
> following comment in the release notes:
>
> "Consider TOAST compression on values as short as 32 bytes
> (previously 256 bytes)"

The 2kB are compared against tuple size. The 32 bytes (previously 256)
are compared against a single column value.

--
Alvaro Herrera http://www.CommandPrompt.com/
PostgreSQL Replication, Consulting, Custom Development, 24x7 support