mysqld --debug=d:t:i:O:n --user=mysql （源码调试)

 --debug=d:t
--debug=d:f,main,subr1:F:L:t,20
--debug=d,input,output,files:n
--debug=d:t:i:O,\mysqld.trace
--debug=d:t:i:O

o	Redirect the debugger output stream to the specified file. The default output is stderr.
O	Like o, but the file is really flushed between each write. When needed, the file is closed and reopened between each write.

--debug=d:t --debug=d:f,main,subr1:F:L:t,20

--debug=d,input,output,files:n

--debug=d:t:i:O,\mysqld.trace

--debug=d:t:i:O

./mysqld  --debug=d:t:i:O:F:L:t:n --user=mysql  详细信息

./mysqld  --debug=d:t:i:O:n --user=mysql      函数调用框架

./mysqld   --debug=d:t:i:O:n:D,20 --user=mysql 延迟两秒

general: Command on socket (7) = 2 (Init DB)   日志中定位命令开始

Flag   Description  

d   Enable output from DBUG_XXX macros for the current state. May be followed by a list of keywords, which enables output only for the DBUG macros with that keyword. An empty list

of keywords enables output for all macros.

In MySQL, common debug macro keywords to enable are enter, exit, error, warning, info, and loop.  

D   Delay after each debugger output line. The argument is the delay, in tenths of seconds, subject to machine capabilities. For example, D,20 specifies a delay of two seconds.  

f   Limit debugging, tracing, and profiling to the list of named functions. An empty list enables all functions. The appropriate d or t flags must still be given; this flag only

limits their actions if they are enabled.  

F   Identify the source file name for each line of debug or trace output.  

i   Identify the process with the PID or thread ID for each line of debug or trace output.  

L   Identify the source file line number for each line of debug or trace output.  

n   Print the current function nesting depth for each line of debug or trace output.  

N   Number each line of debug output.  

o   Redirect the debugger output stream to the specified file. The default output is stderr.  

O   Like o, but the file is really flushed between each write. When needed, the file is closed and reopened between each write.  

p   Limit debugger actions to specified processes. A process must be identified with the DBUG_PROCESS macro and match one in the list for debugger actions to occur.  

P   Print the current process name for each line of debug or trace output.  

r   When pushing a new state, do not inherit the previous state's function nesting level. Useful when the output is to start at the left margin.  

S   Do function _sanity(_file_,_line_) at each debugged function until _sanity() returns something that differs from 0. (Mostly used with safemalloc to find memory leaks.)  

t   Enable function call/exit trace lines. May be followed by a list (containing only one modifier) giving a numeric maximum trace level, beyond which no output occurs for either

debugging or tracing macros. The default is a compile time option