Slides from the ILOUG 2019 conference. The skill set of a database practitioner is much more than what is read in the documentation, on blogs, or on StackOverflow. It is the knowledge from years of trial and error, experimentation, and sometimes painful failures. The problem is it takes time—a long, long time—to build that experience. This session aims to fast-track that path. Get a collection of hints, tips, features, and techniques picked up from the smartest people in the community.

1. 29/01/2019
1
The Fast Lane the Database Success
aka, hints, tips and tricks from an old dude
Connor McDonald
Developer Advocate for Database
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Connor McDonald
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
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Copyright © 2018, Oracle and/or its affiliates. All rights reserved. |
Stuff
youtube bit.ly/youtube-connor
blog bit.ly/blog-connor
twitter bit.ly/twitter-connor
400+ posts mainly on database & development
250 technical videos, new uploads every week
rants and raves on tech and the world :-)
Copyright © 2018, Oracle and/or its affiliates. All rights reserved.
etc...
facebook bit.ly/facebook-connor
linkedin bit.ly/linkedin-connor
instagram bit.ly/instagram-connor
slideshare bit.ly/slideshare-connor
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Copyright © 2018, Oracle and/or its affiliates. All rights reserved.
7https://asktom.oracle.com
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8
https://asktom.oracle.com/officehours
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
150 hours of free access (so far)
9
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why tips and techniques ?
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SO...
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HERE
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IS
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WHAT
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
maybe they were right ?
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I hope not :-)
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
it's not about manuals
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it's not about re-invention
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
it's about sharing
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it's about community
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
that’s why
Copyright © 2019, Oracle and/or its affiliates. All rights reserved. |
Safe Harbor Statement
The following is intended to outline our general product direction. It is intended for
information purposes only, and may not be incorporated into any contract. It is not a
commitment to deliver any material, code, or functionality, and should not be relied
upon in making purchasing decisions. The development, release, and timing of any
features or functionality described for Oracle’s products remains at the sole discretion
of Oracle.
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved. | 27
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
if it's not in the documentation
- contact Support
- clarify usage before proceeding
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
rogue session
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select sid, last_call_et, status,
3 from v$session s;
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 ACTIVE
40 412 INACTIVE
44 421 INACTIVE
46 12 ACTIVE
51 9 ACTIVE
53 15 ACTIVE
58 8 ACTIVE
69 22 ACTIVE
...
80 453 INACTIVE
33
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select sid, last_call_et, status,
3 from v$session s;
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 ACTIVE
40 412 INACTIVE
44 421 INACTIVE
46 12 ACTIVE
51 9 ACTIVE
53 15 ACTIVE
58 8 ACTIVE
69 22 ACTIVE
...
80 453 INACTIVE
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
old days
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
idiot in database
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
much more modern...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
idiot in database
39
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter system kill session ...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
# kill -9 pid
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
38
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 ACTIVE
40 412 INACTIVE
41 412 INACTIVE
44 421 INACTIVE
46 12 ACTIVE
51 9 ACTIVE
53 15 ACTIVE
58 8 ACTIVE
43
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> oradebug setorapid nnn
SQL> oradebug suspend
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 ACTIVE
40 412 INACTIVE
41 412 INACTIVE
44 421 INACTIVE
46 12 ACTIVE
51 9 ACTIVE
53 15 ACTIVE
58 8 ACTIVE
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> oradebug setorapid nnn
SQL> oradebug suspend
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 ACTIVE
40 412 INACTIVE
41 412 INACTIVE
44 421 INACTIVE
45
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> oradebug setorapid nnn
SQL> oradebug suspend
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 ACTIVE
40 412 INACTIVE
41 412 INACTIVE
44 421 INACTIVE
SQL> oradebug resume
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
47
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
maybe ...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
... you don't want to resume
49
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
rogue session
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44
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter system kill session ...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
46
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
18c
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter system cancel sql '123,456';
55
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
bonus tip!
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
maybe...
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select sid,
2 last_call_et,
3 status,
4 from v$session s;
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 ACTIVE
40 412 INACTIVE
44 421 INACTIVE
...
...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select sid,
2 last_call_et,
3 nvl2(lockwait,'BLOCKED',status) status,
4 from v$session s;
SID LAST_CALL_ET STATUS
---------- ------------ ----------
39 7376 BLOCKED
40 412 INACTIVE
44 421 INACTIVE
...
...
59
60

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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select sid, last_call_et,
2 nvl2(lockwait,'BLOCKED',status) status,
3 blocking_session,
4 ( select sql_text
5 from v$sql
6 where sql_id = s.sql_id ) sql_text
7 from v$session s;
SID LAST_CALL_ET STATUS BLOCKING_SESSION SQL_TEXT
---------- ------------ ---------- ---------------- --------------
46 7376 BLOCKED 39 select *
from T
for update
49 4 ACTIVE
50 453 INACTIVE
51 453 INACTIVE
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
select for update wait 60
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select * from T for update wait 60;
(60 seconds pass)
select * from T for update wait 60
*
ERROR at line 1:
ORA-30006: resource busy; acquire with WAIT timeout expired
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
what’s the difference
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
forever is a long time
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SID LAST_CALL_ET STATUS BLOCKING_SESSION
---------- ------------ ---------- ----------------
39 376 INACTIVE
40 412 ACTIVE
41 412 ACTIVE
44 421 ACTIVE
46 340 BLOCKED 39
49 42 ACTIVE
50 453 ACTIVE
51 453 ACTIVE
56 462 BLOCKED 39
58 436 BLOCKED 39
62 278 BLOCKED 46
63 254 BLOCKED 46
67 292 BLOCKED 46
71 301 BLOCKED 46
76 145 BLOCKED 62
78 132 BLOCKED 62
...
...
65
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34
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> create or replace trigger lock_expiry
2 after servererror on database
3 declare
4 l_user varchar2(30);
5 begin
6 if ( is_servererror(30006) ) then
...
... <look up session details>
...
28 raise_application_error(-20000,
29 'User '||l_user||' is causing you grief');
30 end if;
31 end;
32 /
Trigger created.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select * from T for update wait 60;
ERROR at line 1:
ORA-00604: error occurred at recursive SQL level 1
ORA-20000: User CONNOR (ext.1234) is causing you grief
ORA-06512: at line 6
ORA-30006: resource busy; acquire with WAIT timeout expired
67
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
"empowering the users"
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
69
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36. 29/01/2019
36
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
/*+ GATHER_PLAN_STATISTICS */
71
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
64
64
for the optimizer
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
65
65
cardinality is everything
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66
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
66
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
75
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39. 29/01/2019
39
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> explain plan for
2 select count(*)
3 from VEHICLE
4 where MAKE = 'HYUNDAI' and MODEL = 'IONIC';
77
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> explain plan for
2 select count(*)
3 from VEHICLE
4 where MAKE = 'HYUNDAI' and MODEL = 'IONIC';
SQL> SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_PLAN);
--------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
--------------------------------------------------------
| 1 | SORT AGGREGATE | | 1 | 1 |
|* 2 | TABLE ACCESS FULL| VEHICLE | 20K | 270K |
--------------------------------------------------------
78
77
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
? 69
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
actual versus estimate
80
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80

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41
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select /*+ GATHER_PLAN_STATISTICS */ count(*)
2 from VEHICLE
3 where MAKE = 'HYUNDAI' and MODEL = 'IONIC';
COUNT(*)
----------
114468
81
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select /*+ GATHER_PLAN_STATISTICS */ count(*)
2 from VEHICLE
3 where MAKE = 'HYUNDAI' and MODEL = 'IONIC';
COUNT(*)
----------
114468
SQL> SELECT * FROM TABLE(DBMS_XPLAN.DISPLAY_CURSOR(
2 NULL, NULL, 'ALLSTATS LAST'));
-----------------------------------------------------------------
| Id | Operation | Name | Starts | E-Rows | A-Rows |
-----------------------------------------------------------------
| 1 | SORT AGGREGATE | | 1 | 1 | 1 |
|* 2 | TABLE ACCESS FULL| VEHICLE | 1 | 20K| 114K|
-----------------------------------------------------------------
82
81
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42. 29/01/2019
42
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
tracing
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43. 29/01/2019
43
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
alter session set sql_trace = true
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
C:oraclediagrdbmsdb122db122trace>dir *.trc
Volume in drive C is OS
Volume Serial Number is 9CB0-0212
Directory of C:oraclediagrdbmsdb122db122trace
27/09/2018 09:18 PM 1,314 db122_ora_10020.trc
20/10/2018 06:21 PM 2,691 db122_ora_10048.trc
30/09/2018 12:21 AM 1,345 db122_ora_10104.trc
29/09/2018 03:18 PM 1,314 db122_ora_10144.trc
21/10/2018 06:21 AM 1,346 db122_ora_10156.trc
11/10/2018 05:18 PM 1,312 db122_ora_1016.trc
02/10/2018 08:49 PM 1,346 db122_ora_10192.trc
29/09/2018 12:21 PM 1,345 db122_ora_10320.trc
12/10/2018 12:21 AM 1,501 db122_ora_10348.trc
15/10/2018 12:18 AM 1,314 db122_ora_10352.trc
13/10/2018 11:21 AM 1,499 db122_ora_1036.trc
28/09/2018 05:18 AM 1,315 db122_ora_10368.trc
18/10/2018 05:18 PM 1,824 db122_ora_10384.trc
05/10/2018 05:18 AM 1,178 db122_ora_10388.trc
28/09/2018 11:21 PM 1,346 db122_ora_10400.trc
14/10/2018 11:21 PM 1,501 db122_ora_10404.trc
30/09/2018 06:25 AM 1,346 db122_ora_10440.trc
04/10/2018 01:18 PM 1,313 db122_ora_10460.trc
04/10/2018 12:18 PM 1,313 db122_ora_10464.trc
08/10/2018 09:18 AM 1,314 db122_ora_10484.trc
27/09/2018 10:21 PM 1,344 db122_ora_10492.trc
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
09/10/2018 12:18 PM 3,138 db122_ora_11280.trc
15/10/2018 01:18 PM 1,314 db122_ora_11300.trc
16/10/2018 04:21 AM 1,501 db122_ora_11312.trc
06/10/2018 03:21 AM 1,346 db122_ora_11320.trc
15/10/2018 02:22 PM 1,501 db122_ora_11348.trc
18/10/2018 03:21 PM 1,347 db122_ora_11388.trc
16/10/2018 01:21 AM 1,501 db122_ora_11460.trc
06/10/2018 05:21 AM 1,346 db122_ora_11464.trc
18/10/2018 02:21 PM 1,347 db122_ora_11476.trc
15/10/2018 03:21 AM 1,501 db122_ora_11480.trc
29/09/2018 11:21 AM 1,343 db122_ora_1152.trc
04/10/2018 07:21 AM 1,346 db122_ora_11524.trc
07/10/2018 03:21 AM 1,345 db122_ora_11532.trc
28/09/2018 09:18 AM 1,178 db122_ora_11548.trc
02/10/2018 04:21 AM 1,346 db122_ora_11556.trc
20/10/2018 04:18 PM 1,313 db122_ora_11568.trc
05/10/2018 06:21 AM 1,346 db122_ora_11588.trc
28/09/2018 02:18 PM 1,315 db122_ora_11616.trc
16/10/2018 07:21 PM 2,813 db122_ora_11620.trc
30/09/2018 09:21 PM 1,346 db122_ora_11624.trc
15/10/2018 03:18 PM 2,658 db122_ora_11636.trc
01/10/2018 09:21 PM 1,346 db122_ora_11644.trc
18/10/2018 01:21 PM 1,345 db122_ora_11688.trc
07/10/2018 04:21 PM 1,343 db122_ora_1172.trc
18/10/2018 04:21 PM 1,346 db122_ora_11720.trc
23/10/2018 11:21 PM 1,344 db122_ora_11724.trc
20/10/2018 10:21 AM 1,346 db122_ora_11768.trc
05/10/2018 02:21 PM 1,345 db122_ora_11776.trc
28/09/2018 08:18 AM 1,313 db122_ora_11808.trc
11/10/2018 09:21 AM 1,656 db122_ora_11856.trc
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
too many trace files
87
88

45. 29/01/2019
45
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter session
2 set tracefile_identifier = SALESPGM;
Session altered.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter session
2 set tracefile_identifier = SALESPGM;
Session altered.
SQL> host ls *.trc
db10r2_ora_3248.trc
db10r2_ora_3284.trc
db10r2_ora_3356.trc
db10r2_ora_3492.trc
db10r2_ora_3504_SALESPGM.trc
db10r2_ora_3608.trc
db10r2_ora_3620.trc
...
...
89
90

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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
bonus tip
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select name, value from v$diag_info;
91
92

47. 29/01/2019
47
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select name, value from v$diag_info;
NAME VALUE
------------------------ ------------------------------------------
Diag Enabled TRUE
ADR Base C:ORACLE
ADR Home C:ORACLEdiagrdbmsdb122db122
Diag Trace C:ORACLEdiagrdbmsdb122db122trace
Diag Alert C:ORACLEdiagrdbmsdb122db122alert
Diag Incident C:ORACLEdiagrdbmsdb122db122incident
Diag Cdump c:oraclediagrdbmsdb122db122cdump
Health Monitor C:ORACLEdiagrdbmsdb122db122hm
Default Trace File C:ORACLE...tracedb122_ora_17296.trc
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
93
94

48. 29/01/2019
48
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
too much trace data
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter session
2 set events
3 'immediate trace name trace_buffer_on level 1048576';
Session altered.
SQL> host ls –l *.trc
drw------- oracle dba Jun17 15:10 1048576 db10r2_ora_3248.trc
rolling trace window
95
96

49. 29/01/2019
49
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select PAYLOAD
2 from V$DIAG_TRACE_FILE_CONTENTS
3 where TRACE_FILENAME = 'db122_ora_12484.trc';
PAYLOAD
----------------------------------------------------------------------------
Trace file C:ORACLEdiagrdbmsdb122db122tracedb122_ora_12484.trc
Oracle Database 12c Enterprise Edition Release 12.2.0.1.0 - 64bit Production
Build label: RDBMS_12.2.0.1.0WINDBBP_WINDOWS.X64_180202
Windows NT Version V6.2
ORACLE_HOME = c:oracleproduct12.2.0.1
Node name : XPS13
CPU : 4 - type 8664, 2 Physical Cores
Process Affinity : 0x0x0000000000000000
Memory (Avail/Total): Ph:9411M/16235M, Ph+PgF:4292M/20985M
Instance name: db122
Redo thread mounted by this instance: 1
...
...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
97
98

50. 29/01/2019
50
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
19c
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
automatic indexing
99
100

51. 29/01/2019
51
Copyright © 2019, Oracle and/or its affiliates. All rights reserved. |
• The Automatic Indexing
methodology is based on a common
approach to manual SQL tuning
• It identifies candidate indexes and
validates them before implementing
• The entire process is full automatic
• Transparency is equally important as
sophisticated automation
– All tuning activities are auditable via
reporting
87
Automatic Indexing Methodology
Monitor
Online
Validation
Capture
Identify
Verify
Decide
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
until then ...
101
102

52. 29/01/2019
52
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
“I need a new index
on this 6TB table...”
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
“will it speed up things ?”
103
104

53. 29/01/2019
53
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
“I think so”
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
virtual indexes
105
106

54. 29/01/2019
54
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> create index TEST on
2 MYTAB ( SALES_DATE ) NOSEGMENT;
Index created.
data dictionary only
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> begin
2 dbms_stats.generate_stats(
3 'SCOTT',
4 'MYTAB');
5 end;
6 /
107
108

55. 29/01/2019
55
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter session
2 set "_use_nosegment_indexes" = true;
SQL> explain plan for
2 select * from MYTAB
3 where sales_date > sysdate-7;
--------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
--------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 950 | 90109 | 962 (34)|
| 1 | TABLE ACCESS BY INDEX ROWID| MYTAB | 950 | 90109 | 962 (34)|
|* 2 | INDEX RANGE SCAN | TEST | 950 | | 962 (50)|
--------------------------------------------------------------------------
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
109
110

56. 29/01/2019
56
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
97
invisible indexes
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
98
SQL> create table T
2 as select * from all_objects;
Table created.
SQL> create index OBJ_IX on T ( OBJECT_ID );
Index created.
SQL> exec dbms_stats.gather_table_stats('','T')
PL/SQL procedure successfully completed.
111
112

57. 29/01/2019
57
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
99
SQL> set autotrace traceonly explain
SQL> select * from T
2 where OWNER = 'SCOTT'
3 and created > sysdate - 1
4 /
---------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
---------------------------------------------------------------
| 0 | SELECT STATEMENT | | 6 | 546 | 281 (1)|
|* 1 | TABLE ACCESS FULL| T | 6 | 546 | 281 (1)|
---------------------------------------------------------------
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
100
“Can I index OWNER..”
113
114

58. 29/01/2019
58
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
101
“will it speed up things ?”
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
102
“I know so”
115
116

59. 29/01/2019
59
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
103
SQL> create index NEW_IX on T ( OWNER );
Index created.
SQL> select * from T
2 where OWNER = 'SCOTT'
3 and created > sysdate - 1
4 /
---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 6 | 546 | 122 (0)|
|* 1 | TABLE ACCESS BY INDEX ROWID| T | 6 | 546 | 122 (0)|
|* 2 | INDEX RANGE SCAN | NEW_IX | 4107 | | 10 (0)|
---------------------------------------------------------------------------
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
104
117
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
105
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
106
everyone elses queries
119
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61. 29/01/2019
61
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
106
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
107
before the new index
121
122

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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
108
SQL> set autotrace traceonly explain
SQL> select * from T
2 where OWNER = 'SYS'
3 and OBJECT_ID between 10 and 8000
4 /
---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 462 | 42042 | 143 (0)|
|* 1 | TABLE ACCESS BY INDEX ROWID| T | 462 | 42042 | 143 (0)|
|* 2 | INDEX RANGE SCAN | OBJ_IX | 7851 | | 20 (0)|
---------------------------------------------------------------------------
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
109
SQL> set autotrace traceonly stat
SQL> select * from T
2 where owner = 'SYS'
3 and object_id between 10 and 8000;
4967 rows selected.
Statistics
-----------------------------------------------------
0 recursive calls
0 db block gets
784 consistent gets
15 physical reads
0 redo size
123
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
110
after the new index
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
111
SQL> select * from T
2 where owner = 'SYS'
3 and object_id between 10 and 8000
4 /
---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 462 | 42042 | 122 (0)|
|* 1 | TABLE ACCESS BY INDEX ROWID| T | 462 | 42042 | 122 (0)|
|* 2 | INDEX RANGE SCAN | NEW_IX | 4105 | | 10 (0)|
---------------------------------------------------------------------------
the new index
125
126

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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
112
SQL> set autotrace traceonly stat
SQL> select * from T
2 where owner = 'SYS'
3 and object_id between 10 and 8000;
4967 rows selected.
Statistics
------------------------------------------------------
0 recursive calls
0 db block gets
1522 consistent gets
62 physical reads
0 redo size
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
113
127
128

65. 29/01/2019
65
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
114
the solution ?
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
115
invisible indexes
129
130

66. 29/01/2019
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
116
SQL> alter index NEW_IX invisible;
Index altered.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
117
SQL> select * from T
2 where owner = 'SYS'
3 and object_id between 10 and 8000
4 /
----------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
----------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 462 | 42042 | 143 (0)|
|* 1 | TABLE ACCESS BY INDEX ROWID| T | 462 | 42042 | 143 (0)|
|* 2 | INDEX RANGE SCAN | OBJ_IX | 7851 | | 20 (0)|
----------------------------------------------------------------------------
131
132

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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
118
“gee... thanks for nothing”
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
119
SQL> set autotrace traceonly explain
SQL> select * from T
2 where OWNER = 'SCOTT'
3 and created > sysdate - 1
4 /
---------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
---------------------------------------------------------------
| 0 | SELECT STATEMENT | | 6 | 546 | 281 (1)|
|* 1 | TABLE ACCESS FULL| T | 6 | 546 | 281 (1)|
---------------------------------------------------------------
133
134

68. 29/01/2019
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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
120
SQL> alter session set
2 optimizer_use_invisible_indexes = true;
Session altered.
SQL> select * from T
2 where OWNER = 'SCOTT'
3 and created > sysdate - 1
4 /
---------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes | Cost (%CPU)|
---------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 462 | 42042 | 122 (0)|
|* 1 | TABLE ACCESS BY INDEX ROWID| T | 462 | 42042 | 122 (0)|
|* 2 | INDEX RANGE SCAN | NEW_IX | 4105 | | 10 (0)|
---------------------------------------------------------------------------
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
121
wrap your SQL to protect others
135
136

69. 29/01/2019
69
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
122
statement level hint
USE_INVISIBLE_INDEXES
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
137
138

70. 29/01/2019
70
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
better data guard use...
...for free
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> ALTER DATABASE CONVERT TO SNAPSHOT STANDBY;
10.2
139
140

71. 29/01/2019
71
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
open standby read/write
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> ALTER DATABASE CONVERT TO PHYSICAL STANDBY;
SQL> ALTER DATABASE RECOVER MANAGED STANDBY
2 DATABASE DISCONNECT;
10.2
141
142

72. 29/01/2019
72
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
flashback to resetlogs
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
resume managed recovery
143
144

73. 29/01/2019
73
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
archives still transmitted
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
145
146

74. 29/01/2019
74
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
faster queries ... no code changes
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
faster queries ... no code changes
147
148

75. 29/01/2019
75
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> create table cust_trans
2 ( txn_id int,
3 txn_date date,
4 cust_id int,
5 amt number(10,2)
6 );
133
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> insert /*+ APPEND */ into cust_trans
2 select rownum,
3 sysdate-1000+rownum/1000 txn_date,
4 trunc(dbms_random.value(1,1000)) cust_id,
5 dbms_random.value(1,100) amount
6 from
7 ( select 1 from dual
8 connect by level <= 10000000 );
10000000 rows created.
SQL> create index cust_trans_ix
2 on cust_trans (cust_id );
Index created.
134
149
150

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Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select max(amt)
2 from cust_trans
3 where cust_id = 123;
135
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
136
151
152

77. 29/01/2019
77
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select max(amt)
2 from cust_trans
3 where cust_id = 123;
------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 8 |
| 1 | SORT AGGREGATE | | 1 | 8 |
| 2 | TABLE ACCESS BY INDEX ROWID BATCHED| CUST_TRANS | 10010 | 80080 |
|* 3 | INDEX RANGE SCAN | CUST_TRANS_IX | 10010 | |
------------------------------------------------------------------------------
137
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select max(amt)
2 from cust_trans
3 where cust_id = 123;
------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 8 |
| 1 | SORT AGGREGATE | | 1 | 8 |
| 2 | TABLE ACCESS BY INDEX ROWID BATCHED| CUST_TRANS | 10010 | 80080 |
|* 3 | INDEX RANGE SCAN | CUST_TRANS_IX | 10010 | |
------------------------------------------------------------------------------
Statistics
-----------------------------------------------------
0 recursive calls
0 db block gets
8867 consistent gets
8854 physical reads
0 redo size
543 bytes sent via SQL*Net to client
607 bytes received via SQL*Net from client
137
153
154

78. 29/01/2019
78
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
CUST 123 CUST 47 CUST 123 CUST 76 CUST 95 CUST 47 CUST 123
155
156

79. 29/01/2019
79
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> alter table cust_trans
2 add clustering by linear order(cust_id);
Table altered.
SQL> alter table cust_trans move online;
Table altered.
12.1
12.2
139
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select max(amt)
2 from cust_trans
3 where cust_id = 123;
------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 8 |
| 1 | SORT AGGREGATE | | 1 | 8 |
| 2 | TABLE ACCESS BY INDEX ROWID BATCHED| CUST_TRANS | 10010 | 80080 |
|* 3 | INDEX RANGE SCAN | CUST_TRANS_IX | 10010 | |
------------------------------------------------------------------------------
140
157
158

80. 29/01/2019
80
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> select max(amt)
2 from cust_trans
3 where cust_id = 123;
------------------------------------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
------------------------------------------------------------------------------
| 0 | SELECT STATEMENT | | 1 | 8 |
| 1 | SORT AGGREGATE | | 1 | 8 |
| 2 | TABLE ACCESS BY INDEX ROWID BATCHED| CUST_TRANS | 10010 | 80080 |
|* 3 | INDEX RANGE SCAN | CUST_TRANS_IX | 10010 | |
------------------------------------------------------------------------------
Statistics
-----------------------------------------------------
0 recursive calls
0 db block gets
62 consistent gets
23 physical reads
0 redo size
543 bytes sent via SQL*Net to client
607 bytes received via SQL*Net from client
140
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
"but I'm not on 12.2"
159
160

81. 29/01/2019
81
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
dbms_redefinition
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
the marketing spin...
161
162

82. 29/01/2019
82
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> desc EMP
Name Null? Type
----------------------- -------- ----------------
EMPNO NOT NULL NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
MGR NUMBER(4)
HIREDATE DATE
SAL NUMBER(7,2)
COMM NUMBER(7,2)
DEPTNO NUMBER(2)
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> desc EMP
Name Null? Type
----------------------- -------- ----------------
EMPNO NOT NULL NUMBER(8)
SAL_PLUS_10PCT NUMBER(7,2)
163
164

83. 29/01/2019
83
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
online
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> create table EMP_NEW_DEFN(
2 larger_empno number(8),
3 salary_plus_10pct number(7,2));
165
166

84. 29/01/2019
84
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> create table EMP_NEW_DEFN(
2 larger_empno number(8),
3 salary_plus_10pct number(7,2));
SQL> begin
2 DBMS_REDEFINITION.START_REDEF_TABLE( -
3 UNAME =>'SCOTT',
4 ORIG_TABLE =>'EMP',
5 INT_TABLE =>'EMP_NEW_DEFN',
6 COL_MAPPING=>
'empno larger_empno, sal*1.1 salary_plus_10pct'
7 end;
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> exec DBMS_REDEFINITION.FINISH_REDEF_TABLE( -
'SCOTT','EMP','EMP_NEW_DEFN');
167
168

85. 29/01/2019
85
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> exec DBMS_REDEFINITION.FINISH_REDEF_TABLE( -
'SCOTT','EMP','EMP_NEW_DEFN');
SQL> desc EMP
Name Null? Type
-------------------------- -------- -------------------
LARGER_EMPNO NUMBER(8)
SALARY_PLUS_10PCT NUMBER(7,2)
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
169
170

86. 29/01/2019
86
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
PL/SQL programs
triggers
ProC
Java
Reports
ADF
adhoc scripts
BI Publisher layer
APEX
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
171
172

87. 29/01/2019
87
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> begin
2 DBMS_REDEFINITION.START_REDEF_TABLE( -
3 UNAME =>'SCOTT',
4 ORIG_TABLE =>'EMP',
5 INT_TABLE =>'EMP_SAME_DEFN',
6
7 end;
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> begin
2 DBMS_REDEFINITION.START_REDEF_TABLE( -
3 UNAME =>'SCOTT',
4 ORIG_TABLE =>'EMP',
5 INT_TABLE =>'EMP_SAME_DEFN',
6
7 end;
ORDERBY_COLS=>'ename');
173
174

88. 29/01/2019
88
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
DBMS_XPLAN
175
176

89. 29/01/2019
89
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
SQL> explain plan for ...
SQL> select * from
2 table(dbms_xplan.display_plan)
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
extensions
177
178

90. 29/01/2019
90
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
... the (in)famous hint ignore issue
157
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
158
SQL> select *
2 from emp e,
3 dept d
4 where e.deptno = d.deptno
5 and d.dname = 'SALES';
--------------------------------------------------------
| Id | Operation | Name | Rows |
--------------------------------------------------------
| 0 | SELECT STATEMENT | | 5 |
| 1 | MERGE JOIN | | 5 |
|* 2 | TABLE ACCESS BY INDEX ROWID| DEPT | 1 |
| 3 | INDEX FULL SCAN | PK_DEPT | 4 |
|* 4 | SORT JOIN | | 14 |
| 5 | TABLE ACCESS FULL | EMP | 14 |
--------------------------------------------------------
179
180

91. 29/01/2019
91
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
159
"I want a hash join"
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
160
SQL> select /*+ use_hash(d) */ *
2 from emp e,
3 dept d
4 where e.deptno = d.deptno
5 and d.dname = 'SALES';
--------------------------------------------------------
| Id | Operation | Name | Rows |
--------------------------------------------------------
| 0 | SELECT STATEMENT | | 5 |
| 1 | MERGE JOIN | | 5 |
|* 2 | TABLE ACCESS BY INDEX ROWID| DEPT | 1 |
| 3 | INDEX FULL SCAN | PK_DEPT | 4 |
|* 4 | SORT JOIN | | 14 |
| 5 | TABLE ACCESS FULL | EMP | 14 |
--------------------------------------------------------
181
182

92. 29/01/2019
92
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
? 161
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
162
/*+ use_hash(d) */
183
184

93. 29/01/2019
93
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
162
/*+ use_hash(d) */
if joining into DEPT...
use a hash join
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
we're not...
163
185
186

94. 29/01/2019
94
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
164
--------------------------------------------------------
| Id | Operation | Name | Rows |
--------------------------------------------------------
| 0 | SELECT STATEMENT | | 5 |
| 1 | MERGE JOIN | | 5 |
|* 2 | TABLE ACCESS BY INDEX ROWID| DEPT | 1 |
| 3 | INDEX FULL SCAN | PK_DEPT | 4 |
|* 4 | SORT JOIN | | 14 |
| 5 | TABLE ACCESS FULL | EMP | 14 |
--------------------------------------------------------
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
165
if we want to join into DEPT...
...we must be starting with EMP
187
188

95. 29/01/2019
95
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
166
SQL> select /*+ leading(e) use_hash(d) */ *
2 from emp e,
3 dept d
4 where e.deptno = d.deptno
5 and d.dname = 'SALES';
---------------------------------------------------
| Id | Operation | Name | Rows | Bytes |
---------------------------------------------------
| 0 | SELECT STATEMENT | | 5 | 285 |
|* 1 | HASH JOIN | | 5 | 285 |
| 2 | TABLE ACCESS FULL| EMP | 14 | 518 |
|* 3 | TABLE ACCESS FULL| DEPT | 1 | 20 |
---------------------------------------------------
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
not enough hints
167
189
190

96. 29/01/2019
96
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
168
"hints are like violence…
if they do not work, use more"
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
back to dbms_xplan
169
191
192

97. 29/01/2019
97
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
170
SQL> SELECT *
2 from table(dbms_xplan.display(.... ,
format=>'typical +OUTLINE))
/*+ BEGIN_OUTLINE_DATA
USE_HASH(@"SEL$1" "B"@"SEL$1")
USE_HASH(@"SEL$1" "D"@"SEL$1")
LEADING(@"SEL$1" "E"@"SEL$1" "D"@"SEL$1" "B"@"SEL$1")
FULL(@"SEL$1" "B"@"SEL$1")
FULL(@"SEL$1" "D"@"SEL$1")
FULL(@"SEL$1" "E"@"SEL$1")
OUTLINE_LEAF(@"SEL$1")
ALL_ROWS
DB_VERSION('11.2.0.2')
OPTIMIZER_FEATURES_ENABLE('11.2.0.2')
END_OUTLINE_DATA
*/
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
consider SQL Plan Management
171
193
194

98. 29/01/2019
98
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
bonus tip !
172
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
173
SQL> select /*+ INDEX(accounts_pk) */
2 from ACCOUNTS
3 where ...
SQL> select /*+ INDEX(a) */
2 from ACCOUNTS
3 where ...
SQL> select /*+ INDEX(scott.accounts) */
2 from SCOTT.ACCOUNTS
3 where ...
SQL> select /* INDEX(A) */
2 from SCOTT.ACCOUNTS A
3 where ...
195
196

99. 29/01/2019
99
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
19c
174
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
175
SQL> SELECT *
2 from table(dbms_xplan.display(.... ,
format=>'typical +HINT_REPORT'))
197
198

100. 29/01/2019
100
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
finding bad SQL ...
199
200

101. 29/01/2019
101
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
... is probably bad SQL
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
179
SQL> select sql_fulltext
2 from v$sql
3 where buffer_gets > 1000000 or
4 executions > 10000 or
5 disk_reads > 100000;
SQL_FULLTEXT
-----------------------------------------------
SELECT ...
FROM ...
201
202

102. 29/01/2019
102
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
179
SQL> select sql_fulltext
2 from v$sql
3 where buffer_gets > 1000000 or
4 executions > 10000 or
5 disk_reads > 100000;
SQL_FULLTEXT
-----------------------------------------------
SELECT ...
FROM ...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
you can do better
180
203
204

103. 29/01/2019
103
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
181
SQL> select sql_fulltext
2 from v$sqlstats
3 where buffer_gets > 1000000 or
4 executions > 10000 or
5 disk_reads > 100000;
SQL_FULLTEXT
-----------------------------------------------
SELECT ...
FROM ...
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
"The column definitions for columns in V$SQLSTATS are
identical to those in the V$SQL and V$SQLAREA views.
However, the V$SQLSTATS view differs from V$SQL and
V$SQLAREA in that it is faster, more scalable, and has a
greater data retention (the statistics may still appear in
this view, even after the cursor has been aged out of the
shared pool)."
182
205
206

104. 29/01/2019
104
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
184
sqlplus hash tags
207
208

105. 29/01/2019
105
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
185
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
186
SQL> select SAL
2 from EMP
3 where
209
210

106. 29/01/2019
106
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
186
SQL> select SAL
2 from EMP
3 where
"hmmmm....."
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
187
SQL> select SAL
2 from EMP
3 where
211
212

107. 29/01/2019
107
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
187
SQL> select SAL
2 from EMP
3 where
4 #desc EMP
Name Null? Type
----------------------------- -------- -------------
EMPNO NOT NULL NUMBER(4)
ENAME VARCHAR2(10)
JOB VARCHAR2(9)
...
4 job = 'CLERK';
SAL
----------
800
1100
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
188
SQL> declare
2 x int;
3 begin
4 select max(sal)
5 into x
6 from emp;
7
8 dbms_output.put_line(x);
213
214

108. 29/01/2019
108
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
188
SQL> declare
2 x int;
3 begin
4 select max(sal)
5 into x
6 from emp;
7
8 dbms_output.put_line(x);
9 #set serverout on
9 end;
10 /
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
188
SQL> declare
2 x int;
3 begin
4 select max(sal)
5 into x
6 from emp;
7
8 dbms_output.put_line(x);
9 #set serverout on
9 end;
10 /
10000
215
216

109. 29/01/2019
109
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
190
sqlplus error logging
217
218

110. 29/01/2019
110
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
191
SQL> set errorlogging on
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
192
SQL> set errorlogging on
SQL> desc SPERRORLOG
Name Type
------------------------------------- ----------------
USERNAME VARCHAR2(256)
TIMESTAMP TIMESTAMP(6)
SCRIPT VARCHAR2(1024)
IDENTIFIER VARCHAR2(256)
MESSAGE CLOB
STATEMENT CLOB
219
220

111. 29/01/2019
111
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
193
SQL> select * from THE_WRONG_NAME;
select * from THE_WRONG_NAME
*
ERROR at line 1:
ORA-00942: table or view does not exist
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
193
SQL> select * from THE_WRONG_NAME;
select * from THE_WRONG_NAME
*
ERROR at line 1:
ORA-00942: table or view does not exist
SQL> desc THE_WRONG_NAME;
ERROR:
ORA-04043: object THE_WRONG_NAME does not exist
221
222

112. 29/01/2019
112
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
194
SQL> select timestamp, message, statement
2 from SPERRORLOG;
TIMESTAMP
-----------------------------------------------------
MESSAGE
-----------------------------------------------------
STATEMENT
-----------------------------------------------------
01-APR-08 02.29.58.000000 PM
ORA-00942: table or view does not exist
select * from THE_WRONG_NAME
01-APR-08 02.29.58.000000 PM
ORA-04043: object THE_WRONG_NAME does not exist
desc THE_WRONG_NAME;
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
195
installation scripts
SQL> set errorlogging on
SQL> @create_all_objects
223
224

113. 29/01/2019
113
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
197
sqlplus / sqlcl transaction safety
225
226

114. 29/01/2019
114
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
198
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
198
227
228

115. 29/01/2019
115
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
198
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
199
SQL> set exitcommit
229
230

116. 29/01/2019
116
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
wrap up
Copyright © 2019, Oracle and/or its affiliates. All rights reserved.
poaching ideas is fine
231
232

117. 29/01/2019
117
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