Ow Mun Heng schrieb:
On Thu, 2008-07-10 at 09:57 -0400, Alvaro Herrera wrote:
Ow Mun Heng wrote:
This is what I see on the table
NEW attypmod = -1
OLD attypmod = 8
8 means varchar(4) which is what you said you had (4+4)
-1 means unlimited size.
This is cool.
If it were this simple a change, I'm not certain why (I believe) PG is
checking each and every row to see if it will fit into the new column
definition/type.
Thus, I'm still a bit hesitant to do the change, although it is
definitely a very enticing thing to do. ( I presume also that this
change will be instantaneous and does not need to check on each and
every row of the table?)
Thanks./
It should be safe, because the length limit is checked at insert/update
time, and internally, a varchar(20) is treated as something like this:
foo varchar(1000000000) check (length(foo) <= 20)
The change is done without re-checking all rows, and will not fail IF
the new size is longer than the old size.
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