Streams AQ: qmn Coordinator waiting for slave to start

This wait event is reported in the top 5 timed events of node2 with a set of 10g RAC (10.2.0.5) today.

Top 5 timed events

Event	Waits	Time (s)	AVG wait (MS)	% Total call time	Wait class
CPU time		78		123.5
Streams AQ: qmn Coordinator waiting for slave to start	1	6	6,326	10.0	Other
GC Cr block 2-way	11,434	3	0	4.3	Cluster
Control File sequential read	5,090	2	0	2.8	System I/O
DB file sequential read	238	1	4	1.5	User I/O

According to the actual situation, node2 is mainly used for web queries and is the owner of the DMS master. The stream function is not deployed, which is a bit strange.

Analysis Method:

1. check the parameter aq_tm_processes related to stream and find that the value is 0. According to the 10g official documentation, aq_tm_processes = 0 and the qmn monitoring process is not started, it can be started only when it is set to 1 to 10, that is, alter system set aq_tm_processes = 1. You can set it according to the actual situation.

2. As the online master said, "The database load is very low." We have a very low node2.

Note:

The default value and maximum setting range of this parameter are different for 10g and 11g.

The default value of 10g is 0, the range is 1-10, the default value of 11g is 1, and the range is 1-40.

Spam:

The 10g Official documentation really requires the search function to find the parameter definitions. The 11g clearly put the initialization parameter file in a document.