Tom Lane <tgl@sss.pgh.pa.us> wrote:
"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
>> Why not use "ALTER COLUMN SET STORAGE MAIN", to allow compression
>> but avoid external storage?
>
> That only discourages pushing a particular column out; it will still
> do so if the row exceeds TOAST_TUPLE_THRESHOLD after compression.
I thought that's the behavior of EXTENDED. The fine manual says "MAIN
allows compression but not out-of-line storage. (Actually, out-of-line
storage will still be performed for such columns, but only as a last
resort when there is no other way to make the row small enough.)"
If that doesn't mean that it will only use out-of-line storage when
the row doesn't fit in the page, then the manual could use a fix.
-Kevin