Oracle 参数 MAX_DUMP_FILE_SIZE 官方解释，作用，如何配置最优化建议
本站中文解释
MAX_DUMP_FILE_SIZE参数用于控制会话或服务器发生故障时生成的各种dump文件（alert文件和trace文件）中单个dump文件的大小，单位是字节。
MAX_DUMP_FILE_SIZE参数的默认值是10M，但也可以设置为0，表示不限制单个dump文件的大小。可以在pfile或spfile中通过如下语句设置MAX_DUMP_FILE_SIZE参数：ALTER SYSTEM SET MAX_DUMP_FILE_SIZE=10485760 SCOPE=SPFILE；
最佳实践建议为，在设置MAX_DUMP_FILE_SIZE参数的时候，要适当调整这个值，以确保dump文件在记录完整信息的情况下，又不会太大，从而拖慢系统性能，将磁盘空间浪费太多。
官方英文解释
MAX_DUMP_FILE_SIZE specifies the maximum size of trace files (excluding the alert log).
| Property | Description |
|---|---|
|
Parameter type |
String |
|
Syntax |
|
|
Default value |
|
|
Modifiable |
|
|
Modifiable in a PDB |
Yes |
|
Range of values |
0 to unlimited, or |
|
Basic |
No |
You can change this limit if you are concerned that trace files may use too much space.
-
A numeric value for
MAX_DUMP_FILE_SIZEspecifies the maximum size in operating system blocks. -
A numeric value followed by a
KorMorGsuffix specifies the file size in kilobytes, megabytes, or gigabytes. -
The special value string
UNLIMITEDmeans that there is no upper limit on trace file size. Thus, dump files can be as large as the operating system permits.
When the trace file is limited in size, it may be automatically split into multiple files, called segments, if needed. This process is call trace file segmentation. The segments will have the same file name as the active trace file, but with an extra segment number appended.
The trace file can be split into a maximum of 5 segments, and the size of each segment will typically be 1/5th of the trace file limit.
When the combined size of all the trace file segments exceeds the specified limit, the oldest segment is deleted, and a new, empty segment is created. Thus, the trace file always contains the most recent trace information. The first segment is never deleted, because it may contain relevant information about the initial state of the process.
Note that trace file segmentation will not occur when this parameter is set to a value less than 25 MB.
See Also:
Oracle Database
Administrator’s Guide and Oracle Database SQL Tuning
Guide for more information on setting this parameter
