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Does TRUNCATE table free space?
Truncating a table does not give any free space back to the disk – you need to run a SHRINKDATABASE operation for the allocated space to be successfully de-allocated and returned to the disk.
What happens when you TRUNCATE a table in Oracle?
When you truncate a table, Oracle Database automatically removes all data in the table’s indexes and any materialized view direct-path INSERT information held in association with the table. If this direct-path INSERT information is removed, then an incremental refresh of the materialized view may lose data.
What is the difference between the delete and TRUNCATE commands?
The DELETE statement removes rows one at a time and records an entry in the transaction log for each deleted row. TRUNCATE TABLE removes the data by deallocating the data pages used to store the table data and records only the page deallocations in the transaction log. DELETE command is slower than TRUNCATE command.
What happens if we TRUNCATE a table?
The TRUNCATE TABLE statement is used to remove all records from a table in Oracle. It performs the same function as a DELETE statement without a WHERE clause. Warning: If you truncate a table, the TRUNCATE TABLE statement can not be rolled back.
How to delete all table data in Oracle truncate?
Introduction to Oracle TRUNCATE TABLE statement. When you want to delete all data from a table, you use the DELETE statement without the WHERE clause as follows: DELETE FROM table_name; Code language: SQL (Structured Query Language) (sql) For a table with a small number of rows, the DELETE statement does a good job.
What happens to the space after a truncate in Oracle?
A TRUNCATE statement also specifies whether space currently allocated for the table is returned to the containing tablespace after truncation. In previous release 11gR1 when a truncate was executed Oracle keeps the segment associated with a table.
How does a truncate work on a table?
By resetting the High Water Mark, the truncate prevents reading of any table’s data, so they it has the same effect as a delete, but without the overhead. There is, however, one aspect of a Truncate that must be kept in mind.
How to remove a tablespace from an Oracle Database?
Use the DROP TABLESPACE statement to remove a tablespace from the database. When you drop a tablespace, Oracle Database does not place it in the recycle bin. Therefore, you cannot subsequently either purge or undrop the tablespace.