If you want to know more about the AQ internals (and why explicitly setting aq_tm_processes to a value GREATER than 0 isn’t a good idea either), I suggest the Master Note for AQ Queue Monitor Process (QMON) (Doc ID 305662.1) for further reading. As we could not bounce the instance immediately, we set the parameter to 1 for the time being and also removed the setting from the SPFile: alter system set aq_tm_processes=1 Īlter system reset aq_tm_processes scope=spfile If the still issue still exists then it must be a bug 24560906. SQL> ALTER SYSTEM SET streamspoolsize 150m SCOPEboth Restart the Database and then run the export backup. Resetting requires a restart of the DB instance. We are going to change the memory for the streams pool using the below query. Enlarging the streams pool did not help here, by the way. In my customer’s scenario, resetting this parameter to its default and letting QMNC taking control of spawning processes resolved the Data Pump issue. Select 1 into mycheck from v$parameter where name = 'aq_tm_processes' and value = '0'Īnd (ismodified 'FALSE' OR isdefault='FALSE') ĭbms_output.put_line('The parameter ''aq_tm_processes'' is explicitly set to 0!') ĭbms_output.put_line('The parameter ''aq_tm_processes'' is not explicitly set to 0.' There is also Bug 17365043 filed against Versions >= 11.2.0.3, which is unresolved yet, even in 12c.īUT: it’s worth to first check the setting of AQ_TM_PROCESSES as shown in Oracle Support’s “ Master Note for AQ Queue Monitor Process (QMON) (Doc ID 305662.1)” connect / as sysdba blocked due to flow control - Streams AQ: enqueue blocked on low memory.
This is usually a pointer to “streams_pool_size” being set too low (or having ASMM enabled resulting in a shrink operation on the Streams Pool at some point in time). PMgrp0 grant - gc assume - gc block recovery request - gc buffer. When I click on SQL ID, Information has 'The SQL statement is. When I click on Top Activity, I can see that the session belongs to SYS and Program is ORACLE.EXE (MMON). For the past 2 hours, there are spikes of dark brown (Configuration) on the Performance screen in EM every 5 minutes. Running that job again interactively and checking v$session_wait, it showed the Data Pump Master process waiting on “ Streams AQ: Enqueue Blocked On Low Memory“. Streams AQ: enqueue blocked on low memory. A quick diagnosis of that behaviour was achieved by using the “METRICS=Y” argument for expdp. However, if you don’t reset this parameter afterwards, you might run into the following scenario the next time you do a Data Pump export or import:Īt a customer site, regular export jobs that took only minutes to complete suddenly took 2 1/2 hours, seeming to be stuck at the very beginning.
#Streams aq enqueue blocked on low memory upgrade
Unless, of course, you want to disable the Queue Manager Process (QMNC in Oracle 11.x). Which you may want to do during database upgrades to prevent Streams or Advanced Queueing from interfering with the upgrade process. Using the below query you will get PID against SID in the oracle database.Thou shalt not explicitly set AQ_TM_PROCESSES=0 ! In the Linux platform, every process has its process ID (PID) and a user can easily get PID from SID (Identify OS PID from SID). We want to find out OS PID against sid in the Oracle database to check the performance related to OS and Database.
#Streams aq enqueue blocked on low memory how to
View On WordPress high water mark and low water mark in oracle high water mark in sql server high water mark oracle partition high water mark oracle truncate How do I change the high-water mark in Oracle? How do I find a high-water mark on my table? how to check high water mark in oracle tablespace how to resolve high water mark in oracle low water mark in oracle oracle shrink datafile high water mark What is high level watermark? What&039 s high and low-water marks? When we create a table in oracle the HWM is at starting position. In the Oracle database, the data is stored in blocks, and by default one block size is 8KB so you have a table with 10 extents (80K). How does HWM work in the oracle table, what is the High Water Mark? #ORACLEDBA #ORACLEATABASE #ORACLE article will learn how to reset the High Water Mark in the oracle table. How does HWM work in the oracle table, what is the High Water Mark? Datapump Expdp Or Impdp Slowdown Due To Frequent Waits On Streams AQ: Enqueue Blocked On Low Memory' (Doc ID 2386566.1) Two important information: Select shrinkphaseknlasg from XKNLASG Will return 1 if the stream pool is shrinking and return 0 if such action is finished. If you check the session, you’ll find it frequently waiting on Streams AQ: enqueue blocked on low memory, this is due to the BUG 27634991. How to reset the High Water Mark in the oracle table. Sometimes you might find your export job, out of nowhere, starts taking a lot to finish, like if it normally takes 2 hours to end after 5 hours is still running and it’s not even at half the job done.
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