The first step: analysis of the reason
In statspack report, found a lot of the Insert, refer to the result is:
Entities LOB large object table of concurrent insert, update caused by LOB Segment High Water Mark is a common LOB concurrency contention,
In SQL text insert fields were discovered the LOB field,
Countermeasures:
1. The ALTER TABLE & lt; Lob_table & gt;
The MODIFY LOB (& lt; Column_name & gt;) (the allocate among (size & lt; Among other size>) );
Causes of high water level lock because among small, and there are a large number of concurrent insert, then we can move through the increase among to ease frequent high water level,
But this among the size increase how much, I know it is not to judge, according to what
2. The introduction of 44951 event
44951 event LEVEL parameter defines when a LOB under ASSM segment of HWM rises at a time to obtain the number of chunks, generally recommend set to 1024, 1024 the chunk get in a short period of time, due to a single jump HWM higher, this let into enq HW - less contention waiting for chance, it is important to note the 44951 event only to LOB in ASSM tablespace segment effectively,
The alter system set events' 44951 trace name context forever, level 1024 ';
3. BasicFiles migration into SecureFiles storage
Oracle 11 g new function, specific steps slightly!
Above is the project of several conclusions, please forgive me for the first time to write, deficiencies still
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