Help : session stuck with library cache

  • From: "Polarski, Bernard" <Bernard.Polarski@xxxxxxxxxxxxxx>
  • To: <oracle-l@xxxxxxxxxxxxx>
  • Date: Tue, 3 Oct 2006 10:45:40 +0200

I have a connection in perl stuck with latch free latch on 'library
cache' latch# 106:


 Sid       SEQ# Event type                       waits  Time waited
P1         P2         P3 State
----- ---------- ------------------------------ ------- -------------
---------- ---------- ---------- -----------------
   26       7823 latch free                           0             0
1.7199E+10        106          1 WAITING
   60      13128 db file sequential read              0             0
64     151890          1 WAITING
   25         38 SQL*Net message to client           -1             0
1650815232          1          0 WAITED SHORT TIME

Connected to:
Oracle8i Enterprise Edition Release 8.1.7.4.0 - Production
JServer Release 8.1.7.4.0 - Production

SQL> select name from v$latchname where latch#=106 ;
NAME
----------------------------------------------------------------
library cache

Both SQL_HASH_VALUE and PREV_HASH_VALUE are filled in v$session :

SQL   Hash value Sql
---- -----------
------------------------------------------------------------------------
--------
Curr  4174678299 select to_char(hash_value) hv, to_char(piece) pi,
sql_text st from v$sqltext
                                  where hash_value=:hv order by piece

Prev  4174678299 select to_char(hash_value) hv, to_char(piece) pi,
sql_text st from v$sqltext
                                  where hash_value=:hv order by piece

In v$latchholder I got this : 

SID   Latch Address Latch name
--- --------------- -----------
26 000000040123AB50 library cache:

I am a bit stuck, as I can't determine what's happening. The rest of the
DB is advancing. This is on a SAP system with lot of parsing.

Any idea where to search? I would like to determine why session is not
performing the above query or if this query is stuck somewhere.



Regards,

B. Polarski
Oracle DBA


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