Estimate Defragmentaton Benefits for a Bigfile Tablespace

Database: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 – Production Version 19.3.0.0.0 I write this post in order to follow step by step how a bigfile tablespace is created and managed in 19c. The main purpose is to find a way to estimate the space benefits of defragmenting the tablespace. I will use two methods: Method 1. By calculating the theoretical size of the tables. It is outlined below in steps 19-20. The limitation of this calculation is that right now it works for tables only Method 2. By using the Segment Advisor. Outlined below in steps 21-22 1. Check the datafile does not exist at OS level: 2. Create the tablespace as user SYSTEM: 3. Check DB file getting created: 4. Login as ‘radu’ user. Create test tables in the test_tbs tablespace: 5. Check size of the DB file. Should not be changed: 11M 6. Run test SQL: Output: 7. Populate first test table with 9 million rows. Example of block used to populate the table: 8. Check size of the DB file –> 291M 9. Run the control SQL from step 6. Used –> 284M 10. Populate second test table with 9 million rows. 11. Check size of the DB file –> 526M 12. Run the control SQL from step 6. Used –> 500M 13. Delete all the rows from the first test table and commit. 14. Check size of the DB file –> 526M. Unchanged 15. Run […]

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