November 2021
Intermediate to advanced
410 pages
12h 1m
Chinese
Content preview from MongoDB权威指南（第3版）
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348
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第
21
章
21.4
日志
默认情况下，
mongod
会将日志发送到标准输出（
stdout
）。大多数初始化脚本会使用
--logpath
选项将日志发送到文件。如果在一台机器上有多个
MongoDB
实例（比如，一个
mongod
和一个
mongos
）
，那么需要确保它们的日志存储在不同的文件中。确保你知道日
志的位置，并具有对文件的读取访问权限。
MongoDB
会输出很多日志消息
，但是不要使用
--quiet
选项（它会隐藏部分日志消息）。
保留默认的日志级别通常可以工作得很好：有足够的信息可以用于基本的调试（为什么这
么慢？为什么不启动？等等），但同时不会占用太多的空间。
如果要调试应用程序的某个特定问题，那么可以使用一些选项从日志中获取更多信息。可
以运行
setParameter
命令以更改日志级别，或者使用
--setParameter
选项将日志级别作为
字符串传递，从而在启动时对其进行设置：
> db.adminCommand({"setParameter" : 1, "logLevel" : 3})
还可以对特定组件的日志级别进行更改。如果要调试应用程序的某个特定方面，并且需要
更多的信息（但仅来自该组件），这种方式就会很有帮助。本例会将默认日志详细信息设
置为
1
，查询组件详细信息设置为
2
：
> db.adminCommand({"setParameter" : 1, logComponentVerbosity:
{ verbosity: 1, query: { verbosity: 2 }}})
在完成调试之后，记得将日志级别调回 ...
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