I am embarking on an 11g to 12c Oracle DB migration. I will need to do it at least twice, once for testing, a 2nd time fro production. My initial thought is to use expdp/impdp. I export "full" the DB nightly using expdp.
My problem in the past when importing a full DB is it can get squirrely regarding the system schema/users. A full import tries to muck with system schemas (sys, system, sysman...). My new 12c DB is a portable DB, and obviously I want none of the settings or data from the system schemas, that may hose my new DB.
I do however want all of the non system schemas and users, of which there are 5 or so real schemas, and 30 or so "users."
I have been looking for some blogs or documents that address this issue, and can't find any. A pointer to documentation on how to avoid the problems described above would be great.
Also if there are any other gotchas when doing the migration, a heads up on that would be useful as well.
Related
I've got to update the data of an Oracle DB but I'm not the owner and ain't got any Oracle License.
The goal is to explain to my interlocutor how to create a dump from his Oracle DB, to find out how to restore this dump in a DB (a free version of Oracle or something else), update some data in some tables, and then make another dump to send it back to my interlocutor.
So the differents questions I have are:
1- Is it possible to create a dump (maybe in SQL format) without any specifics dependencies to Oracle ?
2- Is there a way to restore this dump in a free lightweight Oracle, or another kind of DB like Postgresql ?
3- Does Oracle, is able to handle any kind of dump et restore it in an Oracle DB or is there any constraints to respect ?
I am very new to Oracle and ain't got, on my personal computer, any possibility to try out the dump/restore by myself; that's why, any help will be appreciated !
1- Is it possible to create a dump (maybe in SQL format) without any specifics dependencies to Oracle ?
Oracle offers Data Pump utilities (export and import) for such purposes. You'd export table (or schema) - result is a ".dmp" file, readable by import utility. You'd then move that file to your own server (see #2 for the rest)
2- Is there a way to restore this dump in a free lightweight Oracle, or another kind of DB like Postgresql ?
On your own server (which could be a laptop; no problem), you'd install a free Oracle Express Edition (XE) database. Currently, the last version is 21c, but some others should still be available in Oracle Technology Network's Download section.
3- Does Oracle, is able to handle any kind of dump et restore it in an Oracle DB or is there any constraints to respect ?
XE database has its limits - from your point of view, the most important is that it can handle up to 12GB of user data. Therefore, if the .dmp file doesn't contain more data than that, you should be able to import it.
Another constraint is the compatibility. Not all exports can be imported into all databases. There's a matrix which shows which versions match; it is available on My Oracle Support site (but you have to have access to it, which you - as you said - don't. Though, generally speaking, "close" Oracle database versions can interchange .dmp files. It would be best if these two database versions match, of course.
I am a java person and not so much familiar with Oracle available features. Please help me.
The requirement is that, we are looking for some virtual(replica/mirror/view) database to be created from Production database just for testing purpose. Once we are done with executing all the automation test cases, delete the virtual database created. So are there any such concepts in Oracle ?
We are on Oracle 12c.
Many apps use same DB(its huge)
PS: We also use docker for deployment and also AWS.
use Rman duplicate to duplicate the test database from production.
https://oracle-base.com/articles/11g/duplicate-database-using-rman-11gr2
you can duplicate from backups or duplicate from active database
You can probably ask your database admin to export the table space to a new test machine which has the same oracle version installed. May require If there are only very few tables, then you can spool your tables out and use sqlloader to load them to a test database ( you will need to manually create the structure of the tables in test environment before hand.
In both cases, you might want to scrub out the sensitive information as per your requirements and standards.
My colleague running Oracle Database (11g) in AIX and they would like to move this DB to RHEL. I already found Link. However I would like to check if someone have already migrated or used any other best tools.
you have several options. As pointed out before, Oracle Data Pump is the easiest approach. It would lift you from every version >=10g upwards (or even back when you use the VERSION= parameter).
The caveat is:
Size of the database - and your downtime requirements.
In terms of larger databases, Transportable Tablespaces is the usual choice. More work as you will have to rebuild meta information such as synonyms, view, plsql, sequences etc - and in your case you'll have to either CONVERT the tablespaces as you are coming from a Big Endiann platform and going to a Little Endiann. DBMS_FILE_TRANSFER could assist you here as it can restore and covert at the same time whereas RMAN will need a 2-phase operation with staging space for it.
You can speed up transportable tablespaces with RMAN Incremental Backups to avoid most of the copy/convert time. And you can ease it with Full Transportable Export/Import (minimum source: 11.2.0.3 - minimum destination: 12.1.0.1) where Data Pump does the manual work of transportable tablespaces.
And of course there are other techniques such as Create-Table-As-Select or Insert-Append-Select options via Database Links and such.
Just see the big slide deck "Upgrade / Migrate / Consolidate to 12.2" for customer examples - and the "Migrate >230Tb in <24 hours" decks on my page: https://mikedietrichde.com/slides/
Cheers,
Mike
Is there some reason you can't just use Oracle Database Pump?
Create the database on RHEL, make sure you use a compatible character set.
https://docs.oracle.com/cd/B19306_01/server.102/b14215/dp_overview.htm
We have application where all logic is implemented in oracle database using pl/sql.
We have different oracle databases for development and production.
When developer make changes in development database after testing we move changes from development database to production database using schema compare tool of toad. Problem here is that developer must have password of production database. We want only admin to know this password.
Can somebody advice me better way of moving changes between databases without need of having production database password, what is best practice for this ?
I posted this question on oracle OTN forums and got some advices there. Maybe it will be interesting for somebody.
Her is a link
I do not recommend to use comparison tools for generating of database migration scripts.
Development and production databases (and also test databases) must be identical except for current changes made by developers in development databases. Generally speaking this assertion is not correct, because there are many kinds of differencies between development and production databases, e.g. partitioned objects, additional objects for audit (triggers, tables), replication-based objects (snapshots), different tablespaces etc.
Every developer must know, what changes were made by him and applied to development database.
If developer was able to change schema and data in developer database, then he/she must be able to create programs for these DDL and DML changes.
To delegate the same developer an ability to run these migration programs on production database is a bad idea. But if you don't have a better way of database migration, then you can use one of following:
1. Configure Oracle authentication by OS. OS authentication allows Oracle to pass
control of user authentication to the operating system.
2. TOAD can save passwords without disclose them. DBA will insert required password
to local TOAD installation at developer PC (if developers use PC).
I need to do a database migration from Oracle 11g to 12c. But I cannot do a direct export and import kind
of a migration since there are a lot of schema changes which are going to happen. I already have the column mappings
in a sparedsheet with old columns and new columns with all details such as data type, constraints, etc.
There are new columns added to many tables are the default values that should be populated are also known.
So what should be the best approach to do this migration?
There are more ways to do this. Start with getting a dba involved.
To minimize production downtime, you could check if making a logical standby database is feasible in your situation. In that case, make the target database a 12c one, that saves for upgrade time.This target database is in sync with the source database at all times and makes it very valuable. Clone the target database and use that clone to test the migration steps. If the migration fails, you can easily re create a new clone to correct the migration process on.
Working in this way could even enable bi-directional replication, replication from the migrated database back to the source database that could make it possible to revert to the original database in the unlikely event that after production start on the new database things don't work as expected.
Start with adding a dba to the project, a good dba can help minimize downtime and reduce risk.