HF installation : DBVerify, Entity Deployer, Data migration

Answer

(1) Why is the entitydeployer invoked during hot fix installation? Is this the mechanism by which database changes which are part of the HF get migrated as part of the HF installation?

- The enititydeployer is invoked for all processes which will need to load the entities into the memory. This is needed as the installation will need to determine the current entity definition and change the database accordingly. Migration takes place in the data migration step.

(2) What does the data migration step do?

- The data migration is the step which will involve calling any DDL or DML statements that might have to be issued to the database. Hence if an HF involves any change to the database or inserting specific configuration data into any of the tables, it will be done using this step.

(3) In sandbox.cfg there is a property called NO_DBVERIFY. This property is set to Y.
Now if we have made changes to the database using HF Installation data migration scripts, will dbverify be bypassed due to this property?

- If the property NO_DBVERIFY is set to Y, then dbverify will be bypassed.

(4) When extensions are made and then dbverify is run, it seems to generate some scripts which involve dropping and rebuilding indexes. Why does this happen?

- When dbverify is run, scripts will be generated to create or drop indexes to get the database in sync with generated XML entity repository. This will take extensions XML into consideration too.

(5) If we set the NO_DBVERIFY property to Y while installing the HF, and then later run dbverify and then manually run the alter scripts, would this be ok?

- Run step 3 of the HF installation process which is running the ant.sh -f HFInstall.xml installHF with the NO_DBVERIFY as Y. Now run dbverify and execute the alter scripts.
Then run the data migration step of the HF installation.