Re: alter table type from double precision to real - Mailing list pgsql-general

Gregory Stark <stark@enterprisedb.com> wrote:
> This could also be due to alignment restrictions on the other columns or the
> row as a whole. If you're curious exactly what's going on and how to optimize
> your table layout send your table definition and we can tell you exactly how
> it's being laid out and where the extra 4 bytes are going.

Here's my table:

create table WaferTestItem (
  WaferID integer NOT NULL REFERENCES Wafer (ID),
  X integer NOT NULL,
  Y integer NOT NULL,
  TestItemID integer NOT NULL REFERENCES TestItem (ID),
  Value double precision NOT NULL,
  PRIMARY KEY (WaferID, X, Y, TestItemID)
);

What happen if type of Value altered to real?