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Real-Time SQL Monitoring using DBMS_SQLTUNE

2017-08-04 16:21 369 查看

Real-Time SQL Monitoring reports are available from three locations:

  • Enterprise Manager - Click the "Performance" tab, then the "SQL Monitoring" link at the bottom-right of the page to display the "Monitored SQL Executions" screen. Click the 
    SQL_ID
     of interest to display the SQL monitoring report.
  • SQL Developer - Available from the "Tools > Monitor SQL" menu.
  • DBMS_SQLTUNE package.

In this article I will demonstrate the use of the 

DBMS_SQLTUNE
 package to display SQL monitoring reports without using Enterprise Manager or SQL Developer. This article has been updated to include additional functionality introduced in Oracle 11g Release 2.

Related articles.

Introduction

Oracle 11g automatically monitors SQL statements if they are run in parallel, or consume 5 or more seconds of CPU or I/O in a single execution. This allows resource intensive SQL to be monitored as it is executing, as well as giving access to detailed information about queries once they are complete.

SQL monitoring requires the 

STATISTICS_LEVEL
 parameter to be set to 'TYPICAL' or 'ALL', and the 
CONTROL_MANAGEMENT_PACK_ACCESS
 parameter set to 'DIAGNOSTIC+TUNING'.

SQL> CONN / AS SYSDBA
Connected.
SQL> SHOW PARAMETER statistics_level

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
statistics_level		     string	 TYPICAL

SQL> SHOW PARAMETER control_management_pack_access

NAME				     TYPE	 VALUE
------------------------------------ ----------- ------------------------------
control_management_pack_access	     string	 DIAGNOSTIC+TUNING

SQL>

MONITOR Hint

The 

MONITOR
 hint switches on SQL monitoring for statements that would not otherwise initiate it.

SELECT /*+ MONITOR */ d.dname, WM_CONCAT(e.ename) AS employees
FROM   emp e
JOIN dept d ON e.deptno = d.deptno
GROUP BY d.dname
ORDER BY d.dname;

REPORT_SQL_MONITOR

The 

REPORT_SQL_MONITOR
 function is used to return a SQL monitoring report for a specific SQL statement. The SQL statement can be identified using a variety of parameters, but it will typically be identified using the 
SQL_ID
 parameter.

The function can accept many optional parameters, shown here, but most of the time you will probably only use the following.

  • SQL_ID
     - The 
    SQL_ID
     of the query of interest. When NULL (the default) the last monitored statement is targeted.
  • SQL_EXEC_ID
     - When the 
    SQL_ID
     is specified, the 
    SQL_EXEC_ID
     indicates the individual execution of interest. When NULL (the default) the most recent execution of the statement targeted by the 
    SQL_ID
     is assumed.
  • REPORT_LEVEL
     - The amount of information displayed in the report. The basic allowed values are 'NONE', 'BASIC', 'TYPICAL' or 'ALL', but the information displayed can be modified further by adding (+) or subtracting (-) named report sections (eg. 'BASIC +PLAN +BINDS' or 'ALL -PLAN'). This is similar to the way DBMS_XPLAN output can be tailored in the later releases. I almost always use 'ALL'.
  • TYPE
     - The format used to display the report ('TEXT', 'HTML', 'XML' or 'ACTIVE'). The 'ACTIVE' setting is new to Oracle 11g Release 2 and displays the output using HTML and Flash, similar to the way it is shown in Enterprise Manager.
  • SESSION_ID
     - Targets a subset of queries based on the specified SID. Use 
    SYS_CONTEXT('USERENV','SID')
     for the current session.

The report accesses several dynamic performance views, so you will most likely access it from a privileged user, or a user granted the 

SELECT_CATALOG_ROLE
 role.

To see it in action, first we make sure we have a monitored statement to work with.

CONN scott/tiger

SELECT /*+ MONITOR */ d.dname, WM_CONCAT(e.ename) AS employees
FROM   emp e
JOIN dept d ON e.deptno = d.deptno
GROUP BY d.dname
ORDER BY d.dname;

Monitored statements can be identified using the 

V$SQL_MONITOR
 view. This view was present in Oracle 11g Release 1, but has additional columns in Oracle 11g Release 2, making it much more useful. It contains an entry for each execution monitored, so it can contain multiple entries for individual SQL statements.

CONN / AS SYSDBA

-- 11gR1
SELECT sql_id, status
FROM   v$sql_monitor;

SQL_ID	      STATUS
------------- -------------------
526mvccm5nfy4 DONE (ALL ROWS)

SQL>

-- 11gR2
SET LINESIZE 200
COLUMN sql_text FORMAT A80

SELECT sql_id, status, sql_text
FROM   v$sql_monitor
WHERE  username = 'SCOTT';

SQL_ID        STATUS              SQL_TEXT
------------- ------------------- --------------------------------------------------------------------------------
526mvccm5nfy4 DONE (ALL ROWS)     SELECT /*+ MONITOR */ d.dname, WM_CONCAT(e.ename) AS employees
FROM   emp e
JOIN dept d ON e.deptno = d.deptno
GROUP BY d.dname
ORDER BY d.dname

SQL>

Once the 

SQL_ID
 is identified, we can generate a report using the 
REPORT_SQL_MONITOR
 function.

SET LONG 1000000
SET LONGCHUNKSIZE 1000000
SET LINESIZE 1000
SET PAGESIZE 0
SET TRIM ON
SET TRIMSPOOL ON
SET ECHO OFF
SET FEEDBACK OFF

SPOOL /host/report_sql_monitor.htm
SELECT DBMS_SQLTUNE.report_sql_monitor(
sql_id       => '526mvccm5nfy4',
type         => 'HTML',
report_level => 'ALL') AS report
FROM dual;
SPOOL OFF

Examples of the output for each available 

TYPE
 are displayed below.

  • TEXT
  • HTML
  • XML
  • ACTIVE - Active HTML available in 11gR2 requires a download of Javascript libraries and a Flash movie from an Oracle website, so must be used on a PC connected to the internet, unless you download the relevant libraries and use the 
    BASE_PATH
     parameter in the function call to identify their location.

REPORT_SQL_MONITOR_LIST

The 

REPORT_SQL_MONITOR_LIST
 function was added in Oracle 11g Release 2 to generate a summary screen, similar to that on the "Monitored SQL Executions" page of Enterprise Manager. There are a number of parameters to filer the content of the report (shown here), but most of the time you will probably only use the 
TYPE
 and 
REPORT_LEVEL
 parameters, similar to those in the 
REPORT_SQL_MONITOR
 function. The query below shows how the function can be used.

SET LONG 1000000
SET LONGCHUNKSIZE 1000000
SET LINESIZE 1000
SET PAGESIZE 0
SET TRIM ON
SET TRIMSPOOL ON
SET ECHO OFF
SET FEEDBACK OFF

SPOOL /host/report_sql_monitor_list.htm
SELECT DBMS_SQLTUNE.report_sql_monitor_list(
type         => 'HTML',
report_level => 'ALL') AS report
FROM dual;
SPOOL OFF

Examples of the output for each available 

TYPE
 are displayed below.

  • TEXT
  • HTML
  • XML
  • ACTIVE - Active HTML is not currently supported, but the parameter list, specifically the 
    BASE_PATH
    , suggest it will be supported in future.

REPORT_SQL_DETAIL

Although not documented as part of Real-Time SQL Monitoring, the 

REPORT_SQL_DETAIL
 function added in Oracle 11g Release 2 returns a report containing SQL monitoring information. Once again, it has several parameters (shown here), but you will probably only use a subset of them to target specific SQL statements, as shown below.

SET LONG 1000000
SET LONGCHUNKSIZE 1000000
SET LINESIZE 1000
SET PAGESIZE 0
SET TRIM ON
SET TRIMSPOOL ON
SET ECHO OFF
SET FEEDBACK OFF

SPOOL /host/report_sql_detail.htm
SELECT DBMS_SQLTUNE.report_sql_detail(
sql_id       => '526mvccm5nfy4',
type         => 'ACTIVE',
report_level => 'ALL') AS report
FROM dual;
SPOOL OFF

Examples of the output for each available 

TYPE
 are displayed below.

Active HTML Reports Offline

As mentioned previously, by default Active HTML available in 11gR2 require a download of Javascript libraries and a Flash movie from an Oracle website, so must be used on a PC connected to the internet. An alternative to this is to download the relevant files to a HTTP server on your network (or local machine) and use the 

BASE_PATH
 parameter to reference those files rather than the Oracle website.

To show this I will create a new directory under a HTTP server on my network and download the relevant files to it.

mkdir -p /var/www/html/sqlmon
cd /var/www/html/sqlmon
wget --mirror --no-host-directories --cut-dirs=1 http://download.oracle.com/otn_software/emviewers/scripts/flashver.js
wget --mirror --no-host-directories --cut-dirs=1 http://download.oracle.com/otn_software/emviewers/scripts/loadswf.js
wget --mirror --no-host-directories --cut-dirs=1 http://download.oracle.com/otn_software/emviewers/scripts/document.js
wget --mirror --no-host-directories --cut-dirs=1 http://download.oracle.com/otn_software/emviewers/sqlmonitor/11/sqlmonitor.swf

When calling functions in the 

DBMS_SQLTUNE
 package, I use the 
BASE_PATH
 parameter with the value of "http://192.168.0.4/sqlmon" so the active report will use the local copies of the files, rather than accessing them from the internet.

SET LONG 1000000
SET LONGCHUNKSIZE 1000000
SET LINESIZE 1000
SET PAGESIZE 0
SET TRIM ON
SET TRIMSPOOL ON
SET ECHO OFF
SET FEEDBACK OFF

SPOOL /host/report_sql_monitor.htm
SELECT DBMS_SQLTUNE.report_sql_monitor(
sql_id       => '526mvccm5nfy4',
type         => 'ACTIVE',
report_level => 'ALL',
base_path    => 'http://192.168.0.4/sqlmon') AS report
FROM dual;
SPOOL OFF

Views

The SQL monitoring functionality accesses a number of existing views, but two new dynamic performance views have been added specifically as part of it.

For more information see:

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