Materialized views is a very old feature (you may remember that it was called snapshots a long time ago). It has all advantages of a view, as you can define any select statement that joins, filters, aggregates, and see it as one table. It has all advantages of a table, as it is stored in one segment, can be indexed, partitioned, have constraints, be compressed, etc. It looks like indexes as it stores data redundantly,…
12.2 Archives - Page 3 of 5 - Blog dbi services
Today at the UKOUG Super Sunday in Birmingham, I had the opportunity to assist at interesting conferences. The first presentation was about Oracle RAC internals and its new features in version 188.8.131.52 on Oracle Cloud. The main new features concern the cache fusion, the undo header hash table, the leaf nodes, and the hang manager. In 12c release 2 in a RAC environment, the cache fusion automatically chooses an optimal path; the cache fusion collects…
Easier than unplug/plug, you can move pluggable databases with remote cloning. It’s the same idea but you don’t have to manage the files yourself: the are shipped through database link. However, this uses the ‘remote file protocol’ and it fails with version mismatch: ORA-17628: Oracle error 17630 returned by remote Oracle server ORA-17630: Mismatch in the remote file protocol version client server
In the previous post I described how simple it is to unplug a PDB and plug it into a newer version CDB. One goal of dictionary separation in the multitenant architecture is to keep system objects on CDB$ROOT only. Knowing that an upgrade does not touch the application metadata and data, does this make PDB upgrade fast as a simple refresh of metadata links?
12.2 is available in the Oracle Public Cloud DBaaS. If you have a 12.1 DBaaS service, there’s no button to upgrade it. I’ll describe all the possible upgrade procedures and the first one, and the most simple, is to create a new DBaaS service in 12.2 and unplug/plug the PDBs to it.
Two years ago I filled an OTN idea to ‘Constrain PDB datafiles into specific directory’ and made it an enhancement request for 12c Release 2. When you provision a PDB, the PDB admin can create tablespaces and put datafiles anywhere in your system. Of course this is not acceptable in a cloud environment. 12.1 has a parameter for directories (PATH_PREFIX) and 12.2 brings CREATE_FILE_DEST for datafiles.
Now that 12.2 is there, in the Oracle Public Cloud Service, I can share the slides of the presentation I made for Oracle Open World: 12cR2 Single-Tenant: Multitenant Features for All Editions from Franck Pachot I’ll give the same session in French, In Geneva on November 23rd at Oracle Switzerland. Ask me if you want an invitation.
A common question is: how to know which indexes are not used, so that I can drop them. If you tried to use index monitoring you probably have seen the limits of it which make it difficult to use. It has been improved in 12.2 so let’s check if it helps to release the stress of performance regression when we drop an index… or not.