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text indexes in comparison query ( tune like query using text index for large tables)

consider text comparison query:
select e.empno,e.ename,d.loc,d.dname from emp e ,dept d
where e.ename like '%'||d.dname||'%'

This is suitable case of use of text indexes if table emp is quite big.

steps:

1 .FROM DBA ---------

GRANT SELECT ON ctxsys.dr$ths_phrase to scott;
GRANT EXECUTE ON CTX_DDL TO scott;

FROM CTXSYS USER ----------------
exec ctx_ddl.create_stoplist('empty_stoplist', 'BASIC_STOPLIST');
exec ctx_ddl.create_preference('matching_lexer', 'BASIC_LEXER');

2.FROM application USER scott ------

CREATE INDEX emp_ename2 ON emp2 (ename) INDEXTYPE IS CTXSYS.CONTEXT parameters ('lexer CTXSYS.matching_lexer');

in order to take benefit of this text index rewrite above query as below :

select e.*
from emp2 e, dept d
where CONTAINS(e.ename, '%'||d.dname||'%')>0


***** Spool outputs along with execution plans *****

SYSTEM session:

1* alter user ctxsys identified by sys
SQL> /

User altered.

SQL> GRANT SELECT ON ctxsys.dr$ths_phrase to scott;

Grant succeeded.

SQL> GRANT EXECUTE ON CTX_DDL TO scott;

Grant succeeded.

SQL> exec ctx_ddl.create_stoplist('empty_stoplist', 'BASIC_STOPLIST');

PL/SQL procedure successfully completed.

SQL> exec ctx_ddl.create_preference('matching_lexer', 'BASIC_LEXER');

PL/SQL procedure successfully completed.


--SCOTT session --

SQL> create table emp2 as select * from emp;

Table created.

SQL> alter table emp2 modify empno number(7);

Table altered.

SQL> alter table emp2 modify ename varchar2(200);

Table altered.

SQL> create sequence s1 ;

Sequence created.

SQL> insert into emp2(empno,ename) select s1.nextval,'SALES' from emp2;

15 rows created.

insert repeated for

30720 rows created.

SQL> commit;

Commit complete.

SQL> insert into emp2(empno,ename) select s1.nextval,'ABCD SALES HOLA' from emp2 where rownum<=1000; 1000 rows created. SQL> select * from dept;

DEPTNO DNAME LOC
---------- -------------- -------------
10 ACCOUNTING NEW YORK
20 RESEARCH DALLAS
30 SALES CHICAGO
40 OPERATIONS BOSTON

SQL> insert into emp2(empno,ename) select s1.nextval,'ABCDACCOUNTINGEXYZ' from emp2;

62440 rows created.

SQL> commit;

Commit complete.

SQL> CREATE INDEX emp_ename2 ON emp2 (ename) INDEXTYPE IS CTXSYS.CONTEXT parameters ('lexer CTXSYS.matching_lexer');

Index created.

SQL> set autotrace traceonly explain
SQL> select e.*
2 from emp2 e, dept d
3 where CONTAINS(e.ename, '%'||d.dname||'%')>0 ;

Execution Plan
----------------------------------------------------------
Plan hash value: 4225699595

-------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 224 | 45696 | 66 (0)| 00:00:01 |
| 1 | NESTED LOOPS | | 224 | 45696 | 66 (0)| 00:00:01 |
| 2 | TABLE ACCESS FULL | DEPT | 4 | 40 | 3 (0)| 00:00:01 |
| 3 | TABLE ACCESS BY INDEX ROWID| EMP2 | 56 | 10864 | 66 (0)| 00:00:01 |
|* 4 | DOMAIN INDEX | EMP_ENAME2 | | | 4 (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

4 - access("CTXSYS"."CONTAINS"("E"."ENAME",'%'||"D"."DNAME"||'%')>0)

Note
-----
- dynamic sampling used for this statement (level=2)

SQL> insert into emp2(empno,ename) select s1.nextval,'bola' from emp2 ;

124880 rows created.

SQL> commit;

Commit complete.

SQL> set autotrace traceonly explain statistics timing on
SQL> select e.*
2 from emp2 e, dept d
3 where CONTAINS(e.ename, '%'||d.dname||'%')>0 ;

124866 rows selected.

Elapsed: 00:00:01.23

Execution Plan
----------------------------------------------------------
Plan hash value: 4225699595

-------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 682 | 135K| 146 (0)| 00:00:02 |
| 1 | NESTED LOOPS | | 682 | 135K| 146 (0)| 00:00:02 |
| 2 | TABLE ACCESS FULL | DEPT | 4 | 40 | 3 (0)| 00:00:01 |
| 3 | TABLE ACCESS BY INDEX ROWID| EMP2 | 170 | 32980 | 146 (0)| 00:00:02 |
|* 4 | DOMAIN INDEX | EMP_ENAME2 | | | 4 (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

4 - access("CTXSYS"."CONTAINS"("E"."ENAME",'%'||"D"."DNAME"||'%')>0)

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
750 recursive calls
0 db block gets
10354 consistent gets
5 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
26 sorts (memory)
0 sorts (disk)
124866 rows processed

SQL> /

124866 rows selected.

Elapsed: 00:00:00.84

Execution Plan
----------------------------------------------------------
Plan hash value: 4225699595

-------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 682 | 135K| 146 (0)| 00:00:02 |
| 1 | NESTED LOOPS | | 682 | 135K| 146 (0)| 00:00:02 |
| 2 | TABLE ACCESS FULL | DEPT | 4 | 40 | 3 (0)| 00:00:01 |
| 3 | TABLE ACCESS BY INDEX ROWID| EMP2 | 170 | 32980 | 146 (0)| 00:00:02 |
|* 4 | DOMAIN INDEX | EMP_ENAME2 | | | 4 (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

4 - access("CTXSYS"."CONTAINS"("E"."ENAME",'%'||"D"."DNAME"||'%')>0)

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
52 recursive calls
0 db block gets
9682 consistent gets
0 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
124866 rows processed

SQL> drop index EMP_ENAME2;

Index dropped.

Elapsed: 00:00:02.93
SQL> ed
Wrote file afiedt.buf

1 select e.*
2 from emp2 e, dept d
3* where e.ename like '%'||d.dname||'%'
SQL>
SQL> /

124866 rows selected.

Elapsed: 00:00:01.01

Execution Plan
----------------------------------------------------------
Plan hash value: 4088618096

---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 43131 | 8087K| 831 (2)| 00:00:10 |
| 1 | NESTED LOOPS | | 43131 | 8087K| 831 (2)| 00:00:10 |
| 2 | TABLE ACCESS FULL| DEPT | 4 | 40 | 3 (0)| 00:00:01 |
|* 3 | TABLE ACCESS FULL| EMP2 | 10783 | 1916K| 207 (2)| 00:00:03 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

3 - filter("E"."ENAME" LIKE '%'||"D"."DNAME"||'%')

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
178 recursive calls
0 db block gets
11239 consistent gets
0 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
5 sorts (memory)
0 sorts (disk)
124866 rows processed

SQL> /

124866 rows selected.

Elapsed: 00:00:01.01

Execution Plan
----------------------------------------------------------
Plan hash value: 4088618096

---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 43131 | 8087K| 831 (2)| 00:00:10 |
| 1 | NESTED LOOPS | | 43131 | 8087K| 831 (2)| 00:00:10 |
| 2 | TABLE ACCESS FULL| DEPT | 4 | 40 | 3 (0)| 00:00:01 |
|* 3 | TABLE ACCESS FULL| EMP2 | 10783 | 1916K| 207 (2)| 00:00:03 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

3 - filter("E"."ENAME" LIKE '%'||"D"."DNAME"||'%')

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
11157 consistent gets
0 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
124866 rows processed

SQL> insert into emp2(empno,ename) select s1.nextval,'z' from emp2;

249760 rows created.

Elapsed: 00:00:02.75


SQL> commit;

Commit complete.

Elapsed: 00:00:00.10
SQL> set autotrace off
SQL> insert into emp2(empno,ename) select s1.nextval,null from emp2;

499520 rows created.

Elapsed: 00:00:06.32
SQL> commit;

Commit complete.

Elapsed: 00:00:00.01
SQL> CREATE INDEX emp_ename2 ON emp2 (ename) INDEXTYPE IS CTXSYS.CONTEXT parameters ('lexer CTXSYS.matching_lexer');

Index created.

Elapsed: 00:00:22.06
SQL> select e.*
2 from emp2 e, dept d
3 where CONTAINS(e.ename, '%'||d.dname||'%')>0
4
SQL>
SQL> set autotrace traceonly explain statistics timing on
SQL>
SQL> /

124866 rows selected.

Elapsed: 00:00:00.86

Execution Plan
----------------------------------------------------------
Plan hash value: 4225699595

-------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1852 | 368K| 356 (0)| 00:00:05 |
| 1 | NESTED LOOPS | | 1852 | 368K| 356 (0)| 00:00:05 |
| 2 | TABLE ACCESS FULL | DEPT | 4 | 40 | 3 (0)| 00:00:01 |
| 3 | TABLE ACCESS BY INDEX ROWID| EMP2 | 463 | 89822 | 356 (0)| 00:00:05 |
|* 4 | DOMAIN INDEX | EMP_ENAME2 | | | 4 (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

4 - access("CTXSYS"."CONTAINS"("E"."ENAME",'%'||"D"."DNAME"||'%')>0)

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
392 recursive calls
0 db block gets
10671 consistent gets
2 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
6 sorts (memory)
0 sorts (disk)
124866 rows processed

SQL> select e.*
2 from emp2 e, dept d
3 where e.ename like '%'||d.dname||'%' ;

124866 rows selected.

Elapsed: 00:00:01.42

Execution Plan
----------------------------------------------------------
Plan hash value: 4088618096

---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 185K| 33M| 2103 (3)| 00:00:26 |
| 1 | NESTED LOOPS | | 185K| 33M| 2103 (3)| 00:00:26 |
| 2 | TABLE ACCESS FULL| DEPT | 4 | 40 | 3 (0)| 00:00:01 |
|* 3 | TABLE ACCESS FULL| EMP2 | 46308 | 8230K| 525 (3)| 00:00:07 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

3 - filter("E"."ENAME" LIKE '%'||"D"."DNAME"||'%')

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
5 recursive calls
0 db block gets
15761 consistent gets
0 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
124866 rows processed

SQL> /

124866 rows selected.

Elapsed: 00:00:01.42

Execution Plan
----------------------------------------------------------
Plan hash value: 4088618096

---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 185K| 33M| 2103 (3)| 00:00:26 |
| 1 | NESTED LOOPS | | 185K| 33M| 2103 (3)| 00:00:26 |
| 2 | TABLE ACCESS FULL| DEPT | 4 | 40 | 3 (0)| 00:00:01 |
|* 3 | TABLE ACCESS FULL| EMP2 | 46308 | 8230K| 525 (3)| 00:00:07 |
---------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

3 - filter("E"."ENAME" LIKE '%'||"D"."DNAME"||'%')

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
0 recursive calls
0 db block gets
15693 consistent gets
0 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
124866 rows processed

SQL> select e.*
2 from emp2 e, dept d
3 where CONTAINS(e.ename, '%'||d.dname||'%')>0;

124866 rows selected.

Elapsed: 00:00:00.82

Execution Plan
----------------------------------------------------------
Plan hash value: 4225699595

-------------------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time |
-------------------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1852 | 368K| 356 (0)| 00:00:05 |
| 1 | NESTED LOOPS | | 1852 | 368K| 356 (0)| 00:00:05 |
| 2 | TABLE ACCESS FULL | DEPT | 4 | 40 | 3 (0)| 00:00:01 |
| 3 | TABLE ACCESS BY INDEX ROWID| EMP2 | 463 | 89822 | 356 (0)| 00:00:05 |
|* 4 | DOMAIN INDEX | EMP_ENAME2 | | | 4 (0)| 00:00:01 |
-------------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

4 - access("CTXSYS"."CONTAINS"("E"."ENAME",'%'||"D"."DNAME"||'%')>0)

Note
-----
- dynamic sampling used for this statement (level=2)


Statistics
----------------------------------------------------------
52 recursive calls
0 db block gets
10242 consistent gets
0 physical reads
0 redo size
2295427 bytes sent via SQL*Net to client
91959 bytes received via SQL*Net from client
8326 SQL*Net roundtrips to/from client
0 sorts (memory)
0 sorts (disk)
124866 rows processed

thoughts on wheel

I wrote this post from mobile phone while coming from office so it is thoughts coming on wheel.

Setting up database connectivity from oracle(10.2.0.4 on RHEL 5.3 64bit) to foreign data source(any odbc compliant database mysql, mssql server, postgres, netezzza )

What softwares you need to have:

-11g Gateway (if connecting to mysql needs patched to 11.1.0.7) or 11.2.0.1 gateway w
-ODBC Driver Manager (download from unixodbc.org)
-ODBC driver [provided by DB vendor or third party like Data Direct technologies]
- 10g software should have interim patch ******* installed for some bugs for mysql.

Here is steps outline:

1. install ODBC Driver Manager [ need check it is right version]
2. install mysql connector [ need check it is right version]
3. prepare /etc/odbc.ini [location given by env variable
and /etc/odbcinst.ini [location given by odbcinst -j -q]
export NZ_ODBC_INI_PATH=/etc
export ODBCSYSINI=/etc
export ODBCINI=/etc/odbc.ini

4. prepare DSN file
5. check connect from isql [dsn_name] -v
6. install oracle gateway
7. preparare initINSTANCENAME.ora in gateway/hs/admin
8. prepare gateway listener with librarries specified in envs
9. start gateway listener
10. create tnsname which addresses to gateway listener
11. create dblink using tnsname name created in 9.
12. test dblink with various cases

Config files you need to create:

1. Odbc.ini and odbcinst.ini for odbc connectivitt.
2. initDG4ODBC.ora in 11g gateway home/hs/admin
3.

Much overlooked : UAT and DEV DB standard

Much over looked thing while building UAT and DEV databases is it does not model Production database. I'v seen people tend to ignoring unless they are pushed hard to keep UAT and DEV databases as much as close to Production database design, Data distribution and Hawrdware/Software environment.

for e.g. There was an Java Application running on Tomcat - Apache on Solaris 10 on on 64 bit SPARC machines.

1. UAT database was refreshed from export dump instead from Physical Hot/Cold/RMAN backup of Prod. Extent size on UAT and Prod was different. Prod had large fragmentation in some tables,indexes. While UAT did not have as it was refreshed from export dump

2. Statistics were gathered in different way than Production.

3. All database were placed on single Disk array on UAT database. Production has three mirrored copies of Redo logs while UAT has no mirrored redo log.

4. Application was using Connection pooling implemented through java developed code in application only (instead using Oracle's default connection pooling or connection pooling of Weblogic etc)

5. UAT middle tier was using different JDBC driver than Production.

Basic questions to understand Oracle 10g RAC

My Friend and old Pupil Jamshed went through couple of interview questions in RAC in Interviews. To help guys like him here I thought of  more possible questions compiled by me on Oracle 10g RAC to hackle your mind for good. It is not Boggling. It will help you better understand the concept of RAC basics(except GCS and GES role)

1. what is node eviction(gud to start with simple question)
2. what is split brain
3. who do your client connect to VIP or public IP? or is it your choice!
4. how can you change VIP
5. can private IP be changed.
6. what does root.sh do when you install 10g RAC.
7. how is virtual IP configured,what is done behind the VIP configuration assistant.
--some simple questions
8. what is client balancing and server side balancing.
9. how does listener handles requests in RAC
10. Have you ever set TAF. If yes ,expalin how does fail over happens
11. how can cache fusion improve or degreade performance.
12. Have you ever faced any performance issue due RAC
13. what is the background process for cache fusion. Does it have anything to do with log writer process.
14. will you increase parallelism if you have RAC, to gain inter instance parallelism. what are the considerations to decide.
15. what is single point of failure in RAC
16. how do you backup voting disk and how do you recover.
17. what information is stored in OCR, what if you loose it. How can you recover it.
18. how many voting disks and OCRs you can have. Why voting disks can be in odd numbers only.
19. A query running fast on one node is very slow on other node. All the nodes have same configurations. What could be the reasons.
20. Does RMAN behave differently in RAC?
21. Can archive logs be placed on ASM disk. what about on RAW.
22. have you ever used OCFS, can you place OCR and voting disks on OCFS.

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