Hi,
i'm searching for a solution for changing the type of a
column, e.g. from varchar(128) to varchar(512), without an ACCESS
EXCLUSIVE lock. The issue is that the relation is nearly 100 million
rows big and in our environment every second of downtime is very bad.
In my current setup a slave database is replicated via skytools, so
changing the relation first on slave, make a master / slave change and
then do the alter table on the other database is one solution for a
minimum downtime. But with postgres 9 I will use wal shipping for
replication and here is the problem. On slave I have just read
permissions and if I do the alter table on the master db a downtime is
occuring and this is what I have to avoid.
regards,
Andi
