简单的引出最近工作的重点内容：后面有机会将会给出一个详细的介绍
When do index pages splits happen?
Index page splits are a part of the DB2 INSERT process. A split happens when DB2 can’t find enough space to save a record in a candidate leaf page. DB2 then splits the page a 50/50 split into two pages (since V9 in case of sequential key inserts we get an asymmetrical page split instead). The process is considered expensive and is even more costly when running in a Data Sharing environment.
How do I find out if I have a problem with splits?
From an accounting trace perspective, a good indication to the number of splits in a Data Sharing environment is an increase in log records written by a task (QWACLRN,QWACLRAB), since DB2 forces two synchronous log writes for each page split.
From a statistics perspective Latch class 6 (QVLSLC06) will be a good indication for a high number of splits in the system.
Since DB2 10 you can also open a special Performance Trace (IFCID 359) to monitor your index splits in a program.
ref:
阅读(1900) | 评论(0) | 转发(0) |
