ALTER INDEX REBUILD ONLINE in Standard Edition Oracle (SE)

Option A

ALTER INDEX IX01 REBUILD ONLINE = 
ALTER INDEX IX01 COALESCE; + ALTER INDEX IX01 SHRINK SPACE;

Effectivity:
This is highly effective option for table which have many INSERT + DELETE operations.
Space could be reduced in the range of 10%-60%.

The downside:
It is slow... and if index is loaded with DML operation prone to locks.

Real examples:

872Mb => 387Mb
571Mb => 304Mb

Option B

Get DDL

SET LONG 1000

SET PAGESIZE 0

SET LINESIZE 400

COL DDL_CMD FOR A400 WORD_WRAP

SET FEEDBACK OFF

SET HEADING OFF

SELECT DBMS_METADATA.get_dependent_ddl('INDEX','GA_W_COUNTERS_HISTORY', 'MY_USER') AS DDL_CMD FROM DUAL;

Drop and Create the Index using the generated DDL.

Automate the process

crontab 

1 6 * * * bash -l /software/oracle/oracle/scripts/rebuild_ix/rebuild_ix.sh

rebuild_ix.sh

#!/bin/bash

WORK_DIR=/software/oracle/oracle/scripts/rebuild_ix

. /etc/sh/orash/oracle_login.sh igt

ORACLE_SID=igt

ORACLE_BASE=/software/oracle

ORACLE_HOME=/software/oracle/121

cd ${WORK_DIR}

sqlplus / as sysdba @rebuild_ix.sql

rebuild_ix.sql

ALTER INDEX USER_A.INDEX_A COALESCE;

ALTER INDEX USER_A.INDEX_A SHRINK SPACE;

ALTER INDEX USER_B.INDEX_B COALESCE;

ALTER INDEX USER_B.INDEX_B SHRINK SPACE;

EXIT;