PARALLEL INDEX CREATION SIGNIFICANTLY INCREASING DATAFILE SIZE IN 12C AND LATER VERSIONS (Doc ID 2760369.1)

Last updated on MARCH 18, 2021

Applies to:

Symptoms

Parallel index creation on Bigfile Tablespace is significantly increasing datafile size in 12c and later versions

In 11.2.0.4,
1.Create a "Bigfile Tablespace"
2.Create a test table
3.Create a index on the test table using PARALLEL clause/option on bigfile TS
4.File size from dba_data_files is showing as 384MB.
select FILE_NAME,sum(bytes)/1024/1024 from dba_data_files where FILE_NAME
like('%<dbfile_name_created_for_bigfile_ts>%') group by FILE_NAME;

Now, by following same steps as above in later versions like 12,18c and 19c,
TS/Datafile size is getting increased to 896MB. Which is high when compared with 11g TS/Datafile size(384MB).

Below is a simple test case from 12c later version

Changes

 DB upgraded from 11g

Cause

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