Hello all! Our company has some headaches in our application development and deployment process. The chief problem is, "creating stages", which to this audience is, cloning a database efficiently, making and testing a few changes, perhaps recording the differences between databases, and then dropping the database. I'm eternally grateful for someone who pointed out that we should be using "CREATE DATABASE ... WITH TEMPLATE". However, this has two big disadvantages. First, it only works if you can kick the users off the clone. Secondly, it still takes time, uses disk space, etc. We have some big databases. I was also thinking about using ZFS with PostgreSQL to do some sort of copy-on-write. However, this would require me to spawn a whole *new* PostgreSQL instance. In both of these cases, you lose your cache... So, I was wondering... could PostgreSQL grow the ability to "CLONE" a database by re-using existing file system blocks, sharing them across databases? This would perhaps be fast, keep the shared memory cache relevant for both the old copy and the clone, and remove WAL overhead. Then, if the block has to be edited, it'd be cloned in memory, and the clone would be flushed. I'm just imagining a world where "deploying" a new version of our software that makes very small catalog changes and tweaks a few rows would be... quick. Quick to try, check, test, and even deploy on live servers. Best, Clark -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
