The reason to trace the CBO is to understand why the Optimizer made some decisions. In this example we are going to see why same query sometimes uses an index and others it doesn’t, same example was explained HERE It is always useful to have a “GOOD” and “BAD” execution, this way it is easier... » read more
You might face this question if you are going though job interviews. and these are some cases where the Optimizer thinks going for a full table scan is better than index scan. 1:- The selectivity of the records is very high: We have this table and range of contents: We have an index and it... » read more
On this activity we are going to generate snapshots on an active standby so we can be able to create AWR reports. This is our setup: We need to perform the following steps to enable AWR reporting from a physical standby database. 1:- Unlock SYS$UMF user and reset the password. SYS$UMF account is used to... » read more
On this activity we are going to create a Physical Standby from a 19c in CDB configuration: These are the details for the primary DB: Our plan is to create a Standby DB with these details: STEPS: 1:- Prepare Primary database Enable force logging and archivelog mode: Create Standby Redo Log (SRL) files: **We are... » read more
On this practice, we are going to configure DATAGUARD BROKER in a new PRIMARY/STANDBY configuration and see what errors we get since this is a new setup. This is our current lab: 1:- Add the DG broker files to ASM on both primary and Standby: 2:- Start DG broker at DB level on both systems:... » read more
On this post we are going to review possible errors we can face while creating a Standby DB with RMAN using an active DB. These are just errors I faced. For some I skipped steps on purpose so we can see the error we would face. You might face these, or others ( or none…)... » read more
Setting up TDE (Transparent Data Encryption) in 19c is very easy and these are the steps needed. 1:- Create a backup of spfile/initfile (it is always a good practice to create a backup before any change on the DB): 2:- Create WALLET directory in both nodes: 3:- Update sqlnet.ora with wallet location (in all nodes):... » read more
In this activity we are going to assume we have GoldenGate software already installed, if not, you can follow these steps here: Oracle GoldenGate 19c: How to install We are are going to replicate schema HR from/to these server: SOURCE (PDB): TARGET (NON CDB): hostname: racnode1 hostname: standbyracnode IP: 192.168.24.1 IP: 192.168.24.3 RDBMS: 19c RDBMS:... » read more
This is going to be a guide for how to install GoldenGate on your source/target servers, just the installation of the software. For the configuration and setting up and running, please check this: Oracle GoldenGate 19c: How to configure Integrated EXTRACT/REPLICAT First of all make sure you have the GoldenGate version that matches your DB.... » read more
While trying to reinstall Oracle Grid Infrastructure 19c on my lab, I was facing this error: The hint here is the CRS-1705: Found 0 configured voting files In this environment I was replacing OCR dg for RECO dg so lets check what each node see: Somehow I did miss to do a scan on node... » read more