3 ms·
If that's the case, then one less problem to deal with, however I remember it was a matter of several minutes.
by rooam-dev 8y ago
If that's the case, then one less problem to deal with, however I remember it was a matter of several minutes.
- anarazel 8y agoThat's only the case if you add a DEFAULT value for the new column. Up until the soon-to-be-released v11 that required updating existing rows. Without a default it's essentially just inserting a single row in a row into an internal catalog table (pg_attribute). With a default in v11, we basically just store the default for a new column out of line, and reference it when the row is read. In either case a lock has to be acquired on the table, which means if there's a longrunning transaction, you can end up blocking for a while...
- rooam-dev 8y agoAh, yes, i think that was the case. Thanks for extra details!