Re: RFD: ALTER COLUMN .. SET STORAGE COMPRESSED; - Mailing list pgsql-hackers

Dawid Kuroczko napsal(a):
> Hello!
> 
> Currently the TOASTing code does its magic when whole tuple is
> larger than TOAST_TUPLE_TARGET which happens to be around 2KB.
> 
> There are times though when one is willing to trade using (fast) CPU to
> reduce amount of (slow) I/O.  A data warehousing types of workload
> most notably.  Rarely used large columns which are likely to compress
> well but are not large enough to trigger inline compression.
> 
> As we already have four types of ALTER COLUMN .. SET STORAGE
> { PLAIN | EXTERNAL | EXTENDED | MAIN } I would like to add
> "COMPRESSED" which would force column compression (if column is
> smaller than some minimun, I guess somwehwere between 16 and 32 bytes).

I think TOAST_TUPLE_TRESHOLD and TOAST_TUPLE_TARGEST should help you. Look int 
tuptoaster.h
    Zdenek