we recently upgraded our db from 11g to 12c, now db with 12.2 version on linux.
the db is mostly of oltp type, having around 150GB application data and tables having approx 5GB to 10Gb in size,
after upgradation the performance of db is degraded, we believe we can improve that by changing db parameters.
Can you pls suggest any oracle parameters to look for to improve performance apart from memory related.
and any parameters specific to 12.2 version ?
Please check wehat is the value of parameter OPTIMIZER_FEATURES_ENABLE i.e. whether you are using 11g optimizer of 12c optimizer. Sometimes 12c optimizer dont perform well along with that check the values of OPTIMIZER_ADAPTIVE_PLANS and OPTIMIZER_ADAPTIVE_STATISTICS. Please refer to this article. I have faced a similar performance issue after migration from 11g to 12.2c, so please share yur feedback after checking these parameter values.
Related
All,
New to Oracle and am tasked with seeing why a query will not complete in 12c but runs totally fine in 11g. The query will complete in 3-4 minutes on 11g, but will sit and process until you cancel it on 12c.
I'd like to view the features that are enabled, primarily anything dealing with query optimization. How can I do this?
youn can take a look at:
v$ses_optimizer_env
v$sys_optimizer_env
That said: I would start to take a look at the execution plan: Maybe the difference is not a question of Features, but a result of different statistics in the given Systems.
Oracle has an option to emulate optimizer behavior from older versions on the new one. Try to add hint OPTIMIZER_FEATURES_ENABLE('your version of 11g') on 12c, or run this statement within the same session before execution of the query on 12c (assume the version of 11g where query is running fine is 11.2.0.4):
ALTER SESSION SET OPTIMIZER_FEATURES_ENABLE='11.2.0.4';
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.
Currently we have a database running on Oracle 10g (10.2.0.2) in production which needs to be up 24/7, but since it is not supported by the data center, both server OS and Oracle database 10g, we have to move to Oracle 12c as agreed by the superiors. I know I can't use a direct expdp/impdp from 10.2.0.2 to 12.2.0.1. And with limited resources, meaning server resources and no access to oracle support to download oracle 10.2.0.5 patch set or any patch set that is available.
What is the safest and best way with minimal downtime option to move it from 10g to 12c? Do I need to install an 11gR2 software and use it to expdp the data?
The impdp should be downward compatible, but what you can do is:
Do the expdp of your 10.2 database with the 12c software
Use the VERSION parameter of expdp and impdp if you still have problems
You have not told us how big your 10.2 database is and whether you have a limited budget or not. Sometimes the 'superiors' want every last transaction accounted for, and the only way to do this is to use Goldengate. So you can setup the target database, take as long as you need to import the data, and all the while goldengate is keeping the source and target in synch. Goldengate is expensive though and should only be necessary if you have terabytes to deal with.
can anyone please let me know that what limitations does oracle apex have,
limitations like Storage, RAM or other.
How long will i be able to use it without licensing the database?
Oracle APEX is a no-cost feature of the Oracle Database. If you use a free Oracle database (Oracle XE) then Oracle APEX is free to use. You can also gain free access to Oracle APEX at http://apex.oracle.com. If wish to use Oracle APEX on the cloud you can do so with Oracle Exadata Express (http://cloud.oracle.com/database) and many other database cloud services. Free cloud 1 month trials may also be available.
i found this in oracle website, and i now understand that storage differ in each version.
With respect to growing needs for storage, Oracle Database 11g XE now offers a full 11GB for user data alone, which is almost threefold increase since previous 4GB limit in Oracle Database 10g XE. Other hardware restrictions remain the same with CPU usage capped at one physical core and memory at 1GB. Oracle Database 11g XE is available immediately for Windows and Linux platforms.
Source:
http://www.oracle.com/technetwork/articles/sql/11g-xe-quicktour-498681.html
We have a requirement to implement replication (of transactions) from a production database to a test database (across a db link). We're using 11g enterprise edition.
This is because it's not just the production data that's needed, the intention is that code releases in the test database would be tested against real-world transactions from the prod system, without the need for those transactions to be done manually. If a transaction fails then in the test system that worked in the prod system, something is wrong with the release.
It doesn't necessarily have to be in real-time however, a delay is acceptable.
There must be zero risk though on the production transactions failing, due an issue with the replication.
What are the options here? I believe Streams is deprecated in 12c, should that be of concern? GoldenGate is additional ££, which I'm afraid rules it out in this case. Some kind of custom trigger-based solution... too much risk on the prod system as far as I can see.
Any advice greatly appreciated!
As of Oracle release 12c (12.1.x), Oracle Advanced Replication and Oracle Streams are being discontinued. Oracle Golden Gate is going to replace all features of Oracle Advanced Replication and Oracle Streams.
Please review this list of possible alternatives (to name a few):
SharePlex
DBVisit
DBConvert