Re: SUBSTRING performance for large BYTEA

On Sat, Aug 18, 2007 at 12:49:09PM -0400, Tom Lane wrote:

> "Joshua D. Drake" <jd@commandprompt.com> writes:
> > Should we consider setting storage external by default for the type?
>
> No.  That would be counterproductive for the more typical case of bytea
> values in the range of some-small-number-of-kilobytes.  Or at least
> I think that's more typical than values that are so large you have to go
> out of your way to fetch them in chunks.

Would it be feasible to add an ALTER TABLE mode

    ... set storage externally-extended cutoff <size> ...

where <size> is the user configurable size of the column
data at which PostgreSQL switches from extended to external
storage strategy ?

Such that large bytea values would be chunkable while
smaller ones wouldn't at the discretion of the DBA.

Karsten
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