Re: alter table type from double precision to real

ssoo@xxxxxxxxxxxxxxx · Mon, 25 Jun 2007 19:57:07 +0900

Gregory Stark <stark@xxxxxxxxxxxxxxxx> 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?