Tuesday, 26 November 2019

SQL Query is really hanged or not



 Monitoring Progress of a SQL Execution Plan / sql query is really hanged or not  

How to see the progress a query is making from within the execution plan used. Using this we can find sql query is really hanged or not.

1. Find the active sessions
2. Monitoring Progress of a SQL Execution Plan
3. DBMS_SQLTUNE.REPORT_SQL_MONITOR

1. Find the active seesions

select sid, serial#, username, status, sql_id,to_char(LOGON_TIME, 'DD-MON-YYYY HH24:MI:SS') AS LOGON, event from v$session where username='&username';
SELECT sql_id, status, sql_text FROM v$sql_monitor WHERE  username='&username' and status not like '%DONE%';
Output:
———–
SQL> select sid, serial#, username, status, sql_id, event from v$session where username='SH';

       SID    SERIAL# USERNAME                       STATUS   SQL_ID        EVENT
---------- ---------- ------------------------------ -------- ------------- ----------
        24         23 SH                             ACTIVE   5mxdwvuf9j3vp direct path read
        27         61 SH                             ACTIVE   5mxdwvuf9j3vp direct path read
SQL>

2. Monitoring Progress of a SQL Execution Plan

column plan_line_id format 9999 heading 'LINE'
column plan_options format a10 heading 'OPTIONS'
column status format a10
column output_rows heading 'ROWS'
break on sid on sql_id on status
SELECT sid, sql_id, status, plan_line_id,
plan_operation || ' ' || plan_options operation, output_rows
FROM v$sql_plan_monitor
WHERE status not like '%DONE%' and sid='&sid' <---
ORDER BY 1,4;

-- OR ---

column plan_line_id format 9999 heading 'LINE'
column plan_options format a10 heading 'OPTIONS'
column status format a10
column output_rows heading 'ROWS'
break on sid on sql_id on status
SELECT sid, sql_id, status, plan_line_id,
plan_operation || ' ' || plan_options operation, output_rows
FROM v$sql_plan_monitor
WHERE status not like '%DONE%'
ORDER BY 1,4;
Ouput:
       SID SQL_ID        STATUS      LINE OPERATION                       ROWS
---------- ------------- ---------- ----- ------------------------- ----------
        24 5mxdwvuf9j3vp EXECUTING      0 SELECT STATEMENT                   0
                                        1 SORT AGGREGATE                     0
                                        2 NESTED LOOPS                      10
                                        3 PARTITION RANGE ALL            23714 <---
                                        4 TABLE ACCESS FULL              23714 <---
                                        5 TABLE ACCESS FULL                 10
        27 5mxdwvuf9j3vp EXECUTING      0 SELECT STATEMENT                   0
                                        1 SORT AGGREGATE                     0
                                        2 NESTED LOOPS                      10
                                        3 PARTITION RANGE ALL            23781 <---
                                        4 TABLE ACCESS FULL              23781 <---
                                        5 TABLE ACCESS FULL                 10

12 rows selected.

SQL> /

       SID SQL_ID        STATUS      LINE OPERATION                       ROWS
---------- ------------- ---------- ----- ------------------------- ----------
        24 5mxdwvuf9j3vp EXECUTING      0 SELECT STATEMENT                   0
                                        1 SORT AGGREGATE                     0
                                        2 NESTED LOOPS                      10
                                        3 PARTITION RANGE ALL            23737 <-- see diff
                                        4 TABLE ACCESS FULL              23737 <-- see diff
                                        5 TABLE ACCESS FULL                 10
        27 5mxdwvuf9j3vp EXECUTING      0 SELECT STATEMENT                   0
                                        1 SORT AGGREGATE                     0
                                        2 NESTED LOOPS                      10
                                        3 PARTITION RANGE ALL            23804 <--- see diff
                                        4 TABLE ACCESS FULL              23804 <--- see diff
                                        5 TABLE ACCESS FULL                 10

12 rows selected.

SQL> /

       SID SQL_ID        STATUS      LINE OPERATION                       ROWS
---------- ------------- ---------- ----- ------------------------- ----------
        24 5mxdwvuf9j3vp EXECUTING      0 SELECT STATEMENT                   0
                                        1 SORT AGGREGATE                     0
                                        2 NESTED LOOPS                      10
                                        3 PARTITION RANGE ALL            23794 <-- see diff
                                        4 TABLE ACCESS FULL              23794 <-- see diff
                                        5 TABLE ACCESS FULL                 10
        27 5mxdwvuf9j3vp EXECUTING      0 SELECT STATEMENT                   0
                                        1 SORT AGGREGATE                     0
                                        2 NESTED LOOPS                      10
                                        3 PARTITION RANGE ALL            23861 <--- see diff
                                        4 TABLE ACCESS FULL              23861 <--- see diff
                                        5 TABLE ACCESS FULL                 10

12 rows selected.

SQL>

We can see the difference. Hence the query is not hanged

3. REPORT_SQL_MONITOR in HTML (OR) TEXT format
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 report_sql_monitor.txt
SELECT DBMS_SQLTUNE.report_sql_monitor(
  sql_id       => '5mxdwvuf9j3vp', <--- SQLID
  type         => 'TEXT',         <--- HTML
  report_level => 'ALL') AS report
FROM dual;
SPOOL OFF

Output
=======
SQL Monitoring Report

SQL Text
------------------------------
SELECT ......

Global Information
------------------------------
 Status              :  EXECUTING <----
 Instance ID         :  1
 Session             :  SH (27:61)
 SQL ID              :  5mxdwvuf9j3vp
 SQL Execution ID    :  16777216
 Execution Started   :  10/26/2016 20:19:01 <---
 First Refresh Time  :  10/26/2016 20:19:05
 Last Refresh Time   :  10/26/2016 20:38:25
 Duration            :  1164s <---
 Module/Action       :  SQL*Plus/-
 Service             :  SYS$USERS
 Program             :  sqlplus@rac2.amitpawardba.com (TNS V1-V3)

Global Stats
======================================================================
| Elapsed |   Cpu   |    IO    | Concurrency | Buffer | Read | Read  |
| Time(s) | Time(s) | Waits(s) |  Waits(s)   |  Gets  | Reqs | Bytes |
======================================================================
|    1172 |      77 |     1095 |        0.00 |    15M | 537K | 114GB |
======================================================================

SQL Plan Monitoring Details (Plan Hash Value=2043253752)
===========================================================================================================================================================
| Id   |        Operation        |   Name    |  Rows   | Cost |   Time    | Start  | Execs |   Rows   | Read | Read  | Activity |     Activity Detail     |
|      |                         |           | (Estim) |      | Active(s) | Active |       | (Actual) | Reqs | Bytes |   (%)    |       (# samples)       |
===========================================================================================================================================================
|    0 | SELECT STATEMENT        |           |         |      |           |        |     1 |          |      |       |          |                         |
|    1 |   SORT AGGREGATE        |           |       1 |      |       811 |   +220 |     1 |        0 |      |       |          |                         |
| -> 2 |    NESTED LOOPS         |           |    5557 | 370M |      1167 |     +4 |     1 |        4 |      |       |          |                         |
| -> 3 |     PARTITION RANGE ALL |           |    919K |  499 |      1167 |     +4 |     1 |    10325 |      |       |          |                         |
| -> 4 |      TABLE ACCESS FULL  | SALES     |    919K |  499 |      1167 |     +4 |     5 |    10325 |    1 | 208KB |          |                         |
| -> 5 |     TABLE ACCESS FULL   | CUSTOMERS |       1 |  403 |      1170 |     +1 | 10326 |        4 | 535K | 114GB |   100.00 | Cpu (35)                |
|      |                         |           |         |      |           |        |       |          |      |       |          | direct path read (1128) |
===========================================================================================================================================================

I hope this article helped you. Your suggestions/feedback are most welcome.


Keep learning... Have a great day!!!







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