Use the deallocate_unused_clause to explicitly deallocate unused space at the end of the index and make the freed space available for other segments in the tablespace.. When a hash partition is coalesced, its contents are redistributed into one or more remaining partitions determined by the hash function.

alter table xxx coalesce; alter index xxx coalesce; The coalesce partition syntax

This optimized behavior differs from earlier releases, when as part of the ALTER TABLE operation Oracle Database updated each row in the newly created column with the default value, and then fired any AFTER UPDATE triggers defined on the table. there is the ability to coalesce a tablespace. The following illustrates the syntax of the Oracle COALESCE () function: COALESCE (e1, e2, ..., en) In this syntax, the COALESCE () function returns the first non-null expression in the list. The Oracle COALESCE () function accepts a list of arguments and returns the first one that evaluates to a non-null value. Coalescing partitions is a way of reducing the number of partitions in a hash partitioned table or index, or the number of subpartitions in a *-hash partitioned table.

COALESCE returns the first non-null expr in the expression list. Followup . deallocate_unused_clause . If all occurrences of expr evaluate to null, then the function returns null.

September 27, 2010 - 3:10 pm UTC . However, the optimized behavior is …

SQL> alter tablespace TEST2 coalesce; Tablespace altered.

First is the honeycomb fragmentation, when the free extents are side by side, and the "Swiss Cheese" fragmentation, when the extents are separated by live segments. Specify COALESCE to instruct Oracle Database to merge the contents of index blocks where possible to free blocks for reuse.

Oracle Database uses short-circuit evaluation. There are two type of space fragmentation in Oracle.

If index is range-partitioned or hash-partitioned, then Oracle Database deallocates unused space from each index partition.

CLEANUP Specify CLEANUP to remove orphaned index entries for records that were previously dropped or truncated by a table partition maintenance operation. You must specify at least two expressions. you are mixing up things here.

The database evaluates each expr value and determines whether it is NULL, rather than evaluating all of the expr values before determining whether any of them is NULL. 1 select a.tablespace_name, a.file_id, a.block_id, a.blocks, b.block_id 2 from dba_free_space a, dba_free_space b 3 where a.tablespace_name = 'TEST2' 4 and b.tablespace_name = 'TEST2' 5 and a.tablespace_name = b.tablespace_name 6 and a.file_id = …