Enqueue Wait events and their descriptions in Oracle Database 10g Enqueue Wait events and their descriptions in Oracle Database 10g Enqueue waits events usually causes problems in busy Oracle databases. But oracle online document only have some of them until 11gR2, not sure why. enq: TX - contention / Oracle / Sql.ru Waits for TX in mode 4 can occur if the session is waiting for an ITL (interested transaction list) slot in a block. This happens when the session wants to lock a row in the block but one or more other sessions have rows locked in the same block, and there is no free ITL slot in the block. Usually, Oracle dynamically adds another ITL slot. Deadlock | Charles Hooper's Oracle Notes Posts about Deadlock written by Charles Hooper. December 6, 2009. Did you know that it is possible for multiple sessions to incorrectly trigger a deadlock on Oracle 11.1.0.6, 11.1.0.7, and 11.2.0.1 by executing a sequence of commands, when the same sequence of commands does not trigger a deadlock on 10.2.0.4?
Week 11: Oracle Database 10g Top 20 DBA Features: Week 11
for 'enq: TX - allocate ITL entry' count=1 wait_time=2929729. name|mode=54580004, usn<<16 | slot=180024, sequence=a720c. After reviewing this trace & related posts from asktom/oracle site we increased initrans value to 15 for the default partitions, considering we could have 15 concurrent sessions of pl/sql procedure. Refer Me for Oracle: Locking issues 47 11 1u6pm5aay1kcm enq: TX - row lock contention name|mode usn<<16 | slot sequence 1415053318 524313 2611 delete from emp where empno = 1 -- Show the second session is waiting cause of row lock contention. Christmas Explain Plan Patterns - Kerry Osborne's Oracle Blog Hi Fei, My experience with obj# in wait events is that the developers were not very consistent about cleaning up after themselves. It is pretty common to see events that are not related to individual objects that have an obj# (presumably because the developers didn’t clear the field), -1 is generally used when an obj# does not apply and the developers have taken the time to set it. Ask TOM Process getting deadlock while updating a table in ... The minimum number of slots is determined by the initrans setting. You've got four sessions (x4 because the update is parallelized too?) updating the rows. These may be filling blocks so there's no space left to record the ITL info. To resolve this, increase the initrans parameter for your table, e.g.: alter table t initrans 16;
Tool I just learned from AOT training that v$session is a gold mine and has lot of information about blocking session and final blocking session. So it was time for me to modify my old blocking lock script. If the script is run on 10g it will only display blocking session. If it is run on…
Ask TOM Process getting deadlock while updating a table in ...
ASH Report - From 12-Feb-08 15:08:55 To 12-Feb-08 15:38:55
... row lock contention' ela= 2992863 name|mode=1415053316 usn<<16 | slot=524310 sequence=1198593 obj#=-1 tim=4185018039 WAIT #2: nam='enq : TX - row lock contention' ela= 2999090 name|mode=1415053316 usn<<16 | slot=524310 sequence ... oracle10g enq:TX - contention等待事件 - 一江水 - 博客园 enq: TX - contention name|mode usn<<16 | slot sequence 从上述结果中可以看到： parameter1表示enqueue的name和mode。parameter2的高16位表示事务的xidusn,低16位表示事务的xidslot,parameter3表示事务的xidsqn，即p2,p3 ... ASH Report - From 12-Feb-08 15:08:55 To 12-Feb-08 15:38:55 ASH Report For BHDB/BHDB4 (1 Report Target Specified) DB Name DB Id Instance Inst num Release RAC Host BHDB 391220044 BHDB4 4 10.2.0.3.0 YES acsdb803 CPUs SGA Size ... Refer Me for Oracle: Locking issues
p1 denotes name|mode ( Type of the lock and lock mode -- 5458 denotes the type and 0006 the mode which is exclusive).select username, v$lock.sid, trunc(id1/power(2,16)) rbs, bitand(id1,to_number('ffff','xxxx'))+0 slotUsername sid RBS slot seq lmode request...
Week 11 Wait Interface. For immediate performance problems not yet captured by ADDM, the 10g wait interface provides valuable data for diagnosis "The database is too slow!" These words are usually uttered with grimness by an unhappy user. Oracle Trace File Interpretation: enq: TX - index ... WAIT #47156432773600: nam='enq: TX - index contention' ela= 113183 name|mode=1415053316 usn<<16 | slot=4259845 sequence=43226 obj#=-1 tim=1329387810694927 I don't understand how to interpret this line. Googling has yielded that name|mode=1415053316 means Transaction in share mode (hex TX04), and that obj# would reference the object in SYS.OBJ$.
Finding the object causing the wait . Here is a query to display the object from the 'enq: TX - allocate ITL entry' wait event (you must have an ASH license to run this SQL script): Oracle Trace File Interpretation: enq: TX - index contention ... WAIT #47156432773600: nam='enq: TX - index contention' ela= 113183 name|mode=1415053316 usn<<16 | slot=4259845 sequence=43226 obj#=-1 tim=1329387810694927 I don't understand how to interpret this line. Googling has yielded that name|mode=1415053316 means Transaction in share mode (hex TX04), and that obj# would reference the object in SYS.OBJ$.