-- https://easyteam.fr/limpact-du-facteur-dordonnancement-sur-les-performances-clustering-factor/

create pluggable database NIHILUS admin user NIHILUS$OWNER identified by secret;
alter pluggable database NIHILUS open;
alter pluggable database NIHILUS save state;


alter session set container=NIHILUS;

create tablespace USERS datafile size 32M autoextend ON next 32M;
alter database default tablespace USERS;

create user adm identified by "secret";
grant sysdba to adm;

create user usr identified by "secret";
grant CONNECT,RESOURCE to usr;
grant alter session to usr;
alter user usr quota unlimited on USERS;

alias adm_NIHILUS='rlwrap sqlplus adm/"secret"@bakura:1521/NIHILUS as sysdba'
alias usr_NIHILUS='rlwrap sqlplus usr/"secret"@ba



create table USR.TABLE_LIST_DISPLAY_PATTERNS (
	LIST_ID number not null,
	DISPLAY_PATTERN_ID varchar(1000) not null
);


begin
	for i in 1..100 loop
		insert into USR.TABLE_LIST_DISPLAY_PATTERNS select i, lpad('x',1000,'x') from dba_objects where rownum < 35 order by 1;
	end loop;
end;
/
commit;


create index USR.LIST_DISPLAY_PATTERNS_IDX on USR.TABLE_LIST_DISPLAY_PATTERNS(LIST_ID);


create table USR.TABLE_LIST_DISPLAY_RAND as 
	select * from USR.TABLE_LIST_DISPLAY_PATTERNS order by DBMS_RANDOM.RANDOM;

create index USR.LIST_DISPLAY_RAND_IDX on USR.TABLE_LIST_DISPLAY_RAND(LIST_ID);

exec dbms_stats.gather_table_stats('USR','TABLE_LIST_DISPLAY_PATTERNS', method_opt=>'for all columns size AUTO');
exec dbms_stats.gather_table_stats('USR','TABLE_LIST_DISPLAY_RAND', method_opt=>'for all columns size AUTO');




SQL> @tab USR.TABLE_LIST_DISPLAY_PATTERNS
Show tables matching condition "%USR.TABLE_LIST_DISPLAY_PATTERNS%" (if schema is not specified then current user's tables only are shown)...

OWNER                TABLE_NAME                     TYPE     NUM_ROWS        BLOCKS     EMPTY AVGSPC ROWLEN TAB_LAST_ANALYZED   DEGREE                                   COMPRESS
-------------------- ------------------------------ ---- ------------ ------------- --------- ------ ------ ------------------- ---------------------------------------- --------
USR                  TABLE_LIST_DISPLAY_PATTERNS    TAB          3400           496         0      0   1004 2023-06-25 15:41:27          1                               DISABLED

1 row selected.

SQL> @ind USR.LIST_DISPLAY_PATTERNS_IDX
Display indexes where table or index name matches %USR.LIST_DISPLAY_PATTERNS_IDX%...

TABLE_OWNER          TABLE_NAME                     INDEX_NAME                     POS# COLUMN_NAME                    DSC
-------------------- ------------------------------ ------------------------------ ---- ------------------------------ ----
USR                  TABLE_LIST_DISPLAY_PATTERNS    LIST_DISPLAY_PATTERNS_IDX         1 LIST_ID


INDEX_OWNER          TABLE_NAME                     INDEX_NAME                     IDXTYPE    UNIQ STATUS   PART TEMP  H     LFBLKS           NDK   NUM_ROWS       CLUF LAST_ANALYZED       DEGREE VISIBILIT
-------------------- ------------------------------ ------------------------------ ---------- ---- -------- ---- ---- -- ---------- ------------- ---------- ---------- ------------------- ------ ---------
USR                  TABLE_LIST_DISPLAY_PATTERNS    LIST_DISPLAY_PATTERNS_IDX      NORMAL     NO   VALID    NO   N     2          7           100       3400        551 2023-06-25 15:41:27 1      VISIBLE


-- each LIST_ID is stored in how many distinct blocks?

alter session set current_schema=USR;

select 
	norm.list_id, norm.cnt normanized_blocks , random.cnt randomanized_blocks
from
	(select list_id, count(distinct(dbms_rowid.ROWID_BLOCK_NUMBER(rowid))) cnt
		from TABLE_LIST_DISPLAY_PATTERNS
		group by list_id)norm 
,
	( select list_id, count(distinct(dbms_rowid.ROWID_BLOCK_NUMBER(rowid))) cnt
		from TABLE_LIST_DISPLAY_RAND
		group by list_id) random
		where norm.list_id = random.list_id
order by list_id;




set lines 256 pages 999

var LID NUMBER;
execute :LID:=20;

select /*+ GATHER_PLAN_STATISTICS */
	* from USR.TABLE_LIST_DISPLAY_PATTERNS where LIST_ID=:LID;


select * from table(dbms_xplan.display_cursor(null,null,'ALLSTATS LAST  +PEEKED_BINDS +PARALLEL +PARTITION +COST +BYTES'));

-------------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                           | Name                        | Starts | E-Rows |E-Bytes| Cost (%CPU)| A-Rows |   A-Time   | Buffers |
--------------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                    |                             |      1 |        |       |     7 (100)|     34 |00:00:00.01 |      14 |
|   1 |  TABLE ACCESS BY INDEX ROWID BATCHED| TABLE_LIST_DISPLAY_PATTERNS |      1 |     34 | 34136 |     7   (0)|     34 |00:00:00.01 |      14 |
|*  2 |   INDEX RANGE SCAN                  | LIST_DISPLAY_PATTERNS_IDX   |      1 |     34 |       |     1   (0)|     34 |00:00:00.01 |       5 |
--------------------------------------------------------------------------------------------------------------------------------------------------


select /*+ GATHER_PLAN_STATISTICS */
	* from USR.TABLE_LIST_DISPLAY_RAND where LIST_ID=:LID;



select * from table(dbms_xplan.display_cursor(null,null,'ALLSTATS LAST  +PEEKED_BINDS +PARALLEL +PARTITION +COST +BYTES'));

----------------------------------------------------------------------------------------------------------------------------------------------
| Id  | Operation                           | Name                    | Starts | E-Rows |E-Bytes| Cost (%CPU)| A-Rows |   A-Time   | Buffers |
----------------------------------------------------------------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT                    |                         |      1 |        |       |    35 (100)|     34 |00:00:00.01 |      39 |
|   1 |  TABLE ACCESS BY INDEX ROWID BATCHED| TABLE_LIST_DISPLAY_RAND |      1 |     34 | 34136 |    35   (0)|     34 |00:00:00.01 |      39 |
|*  2 |   INDEX RANGE SCAN                  | LIST_DISPLAY_RAND_IDX   |      1 |     34 |       |     1   (0)|     34 |00:00:00.01 |       5 |
----------------------------------------------------------------------------------------------------------------------------------------------