How to find Current open Cursors in Oracle

Question

What is the query to find the number of current open cursors in an Oracle Instance?

Also, what is the accuracy/update frequency of this data?

I am using Oracle 10gR2

Troche

Answer 1

Total cursors open, by session:

select a.value, s.username, s.sid, s.serial#
from v$sesstat a, v$statname b, v$session s
where a.statistic# = b.statistic#  and s.sid=a.sid
and b.name = 'opened cursors current';

Source: http://www.orafaq.com/node/758

As far as I know queries on v$ views are based on pseudo-tables ("x$" tables) that point directly to the relevant portions of the SGA, so you can't get more accurate than that; however this also means that it is point-in-time (i.e. dirty read).

Mongoloid

These 'opened cursors current' are lazily reaped by the Oracle table server; so the number you see for your application may be anomalously high without meaning you made a mistake. See orafaq.com/node/758 – Pandybat

If this doesn't work for you, try first granting yourself the required privileges with command: sqlplus "/ as sysdba" – Clastic

Answer 2

select  sql_text, count(*) as "OPEN CURSORS", user_name from v$open_cursor
group by sql_text, user_name order by count(*) desc;

appears to work for me.

Conjugation

Answer 3

Here's how to find open cursors that have been parsed. You need to be logged in as a user with access to v$open_cursor and v$session.

COLUMN USER_NAME FORMAT A15

SELECT s.machine, oc.user_name, oc.sql_text, count(1) 
FROM v$open_cursor oc, v$session s
WHERE oc.sid = s.sid
GROUP BY user_name, sql_text, machine
HAVING COUNT(1) > 2
ORDER BY count(1) DESC
;

If gives you part of the SQL text so it can be useful for identifying leaky applications. If a cursor has not been parsed, then it does not appear here. Note that Oralce will sometimes keep things open longer than you do.

Onesided

Actually, this is a complex situation. v$open_cursor happens to show cached statements. Open cursors (the resource that can be hammered if you have a cursor / ResultSet leak) is in v$sessstat in a row named 'opened cursors current'. – Pandybat

@Ollie: But how does that help you identify the SQL statement that is leaking? – Onesided

This select shows you the actual SQL code that opened the cursors, great for debugging ! +1 from me – Heaviside

Answer 4

1)your id should have sys dba access 2)

select sum(a.value) total_cur, avg(a.value) avg_cur, max(a.value) max_cur, 
 s.username, s.machine
 from v$sesstat a, v$statname b, v$session s 
 where a.statistic# = b.statistic# and s.sid=a.sid
 and b.name = 'opened cursors current' 
 group by s.username, s.machine
 order by 1 desc;

Rwanda

Answer 5

Oracle has a page for this issue with SQL and trouble shooting suggestions.

"Troubleshooting Open Cursor Issues" http://docs.oracle.com/cd/E40329_01/admin.1112/e27149/cursor.htm#OMADM5352

Cassimere

Answer 6

I would use this quick SQL to compare the highest current use compared to the max allowed. This will allow you to immediately see if any process has a dangerously high use of cursors.

SELECT MAX (a.VALUE) AS highest_open_cur, p.VALUE AS max_open_cur
FROM v$sesstat a, v$statname b, v$parameter p
WHERE a.statistic# = b.statistic#
AND b.name = 'opened cursors current'
AND p.name = 'open_cursors'
GROUP BY p.VALUE;

As is probably clear from the above SQL, the OPEN_CURSORS value is an Oracle parameter and can be found at runtime like this.

SELECT * FROM v$parameter WHERE NAME = 'open_cursors';

You may need to be sysdba or equivalent to query the above tables.

Sassanid

Answer 7

I use something like this:

select 
  user_name, 
  count(*) as "OPEN CURSORS" 
from 
  v$open_cursor 
group by 
  user_name;

Paymaster

Answer 8

This could work:

SELECT    sql_text "SQL Query", 
          Count(*) AS "Open Cursors" 
FROM      v$open_cursor 
GROUP BY  sql_text 
HAVING    Count(*) > 2 
ORDER BY  Count(*) DESC; 

Kagu