Thread

1. How to handle application connectivity change when moving from Oracle to Postgres in GCP

   kunwar singh <krishsingh.111@gmail.com> — 2023-09-10T17:43:18Z

   Hi Listers,
   
   Say we have this App->DB connectivity Model.
   
   APP1
   Contains synonyms which point to objects under APP1.
   
   APPOWN
   Contains the tables, indexes
   
   And it is a Java application that connects to APP1.
   
   Now when the database is switched from Oracle 19c onprem to CloudSQL
   Postgres say v15.
   Questions that I have:
   
   1. What needs to be done at the database end in terms of schema setup in
   order to ensure the application is able to connect to the relevant tables
   without any concerns?
   2. Do I need to create users APP1 and APPOWN in postgres? If so, what
   privileges are required to be assigned to these?
   3. How to tie them with service accounts?
   4. With which username/service account does the application make
   connection to the database?
   
   I still don't understand user/schema concepts in postgres tbh as I'm
   still a noob :)
   
   
   
   -- 
   Cheers,
   Kunwar
   

2. Re: How to handle application connectivity change when moving from Oracle to Postgres in GCP

   Erik Brandsberg <erik@heimdalldata.com> — 2023-09-10T17:55:50Z

   Keep in mind that it is likely that a significant portion of the data
   access code may need to be rewritten unless you are using an ORM that does
   the conversion for you.  Most apps can't be migrated directly from Oracle
   to Postgres.  Based on the questions you are asking, I seriously suggest
   you contact a company that assists with migrations in order to answer your
   questions and highlight the issues you may be facing.
   
   On Sun, Sep 10, 2023 at 1:43 PM kunwar singh <krishsingh.111@gmail.com>
   wrote:
   
   > Hi Listers,
   >
   > Say we have this App->DB connectivity Model.
   >
   > APP1
   > Contains synonyms which point to objects under APP1.
   >
   > APPOWN
   > Contains the tables, indexes
   >
   > And it is a Java application that connects to APP1.
   >
   > Now when the database is switched from Oracle 19c onprem to CloudSQL
   > Postgres say v15.
   > Questions that I have:
   >
   > 1. What needs to be done at the database end in terms of schema setup in
   > order to ensure the application is able to connect to the relevant tables
   > without any concerns?
   > 2. Do I need to create users APP1 and APPOWN in postgres? If so, what
   > privileges are required to be assigned to these?
   > 3. How to tie them with service accounts?
   > 4. With which username/service account does the application make
   > connection to the database?
   >
   > I still don't understand user/schema concepts in postgres tbh as I'm
   > still a noob :)
   >
   >
   >
   > --
   > Cheers,
   > Kunwar
   >
   

3. RE: How to handle application connectivity change when moving from Oracle to Postgres in GCP

   Mike Sofen <msofen@runbox.com> — 2023-09-10T18:32:50Z

   From: kunwar singh <krishsingh.111@gmail.com>  Sent: Sunday, September 10, 2023 10:43 AM
   To: pgsql-sql@lists.postgresql.org
   Subject: How to handle application connectivity change when moving from Oracle to Postgres in GCP
   
    
   
   Hi Listers,
   
    
   
   Say we have this App->DB connectivity Model.
   
    
   
   APP1
   
   Contains synonyms which point to objects under APP1.
   
    
   
   APPOWN
   
   Contains the tables, indexes
   
    
   
   And it is a Java application that connects to APP1.
   
    
   
   Now when the database is switched from Oracle 19c onprem to CloudSQL Postgres say v15.
   
   Questions that I have:
   
    
   
   1. What needs to be done at the database end in terms of schema setup in order to ensure the application is able to connect to the relevant tables without any concerns? 
   
   2. Do I need to create users APP1 and APPOWN in postgres? If so, what privileges are required to be assigned to these?
   
   3. How to tie them with service accounts?
   
   4. With which username/service account does the application make  connection to the database?
   
    
   
   I still don't understand user/schema concepts in postgres tbh as I'm still a noob :) 
   
    
   
    
   
    
   
   -- 
   
   Cheers,
   Kunwar
   
    
   
    
   
   Kunwar, 
   
   Since you mentioned CloudSQL (Google Cloud’s db platform for postgres, mysql, and sql server), I recommend contacting your rep at Google Cloud on this topic.  They just went GA on their DMS product (Data Migration Service) for Oracle to CloudSQL-Postgres migrations (and AlloyDB shortly) – pretty good timing.  DMS converts schema and code, understands most permissions and security pieces, and most importantly, has great tech support.  Usually there is no charge for using DMS (Google underwrites the cost since you’re migrating to their platform).  
   
    
   
   Mike