Tom, Well... there's a lot of data hiding in each of those rows... as much as 4MB in each. I'll make allowances in my code so that adding a column without a default is a workable solution.
Thank you, Eric On Nov 1, 2011, at 8:27 PM, Tom Lane wrote: > Eric Smith <eric_h_sm...@mac.com> writes: >> Thank you for the response... to be perfectly honest, I don't know enough to >> know what I'm not telling you. Below is the string I use to create the >> table, so you can see the contents. I don't think I have foreign key >> references or triggers of any kind. Any ideas? (this is 8.3 running on Mac >> OS 10.7) > > I'm wondering how much data is hiding behind this column: > >> [tableString appendString:@"\"imageData\" bytea null,"]; > > Since you're installing a non-null column default value, the ALTER TABLE > ADD COLUMN command has to rewrite the entire table. If there are large > images hiding in each of those "only 14000" rows, there'd be a lot of > data to copy over and so it could take awhile. > > (In contrast, ADD COLUMN without a default value is speedy because > Postgres plays some tricks to avoid rewriting the table data. That > won't help you if you have to install non-null values in the new > column, but it's good to know that there's a difference.) > > regards, tom lane -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
