mysqli::debug()

(PHP 5, PHP 7)

Performs debugging operations

说明

面向对象风格
mysqli::debug(string $message): bool

过程化风格
mysqli_debug(string $message): bool

Performs debugging operations using the Fred Fish debugging library.

参数

$message

A string representing the debugging operation to perform

返回值

Returns TRUE.

注释

Note:

To use the mysqli_debug() function you must compile the MySQL client library to support debugging.

范例

Example #1 Generating a Trace File

<?php
/* Create a trace file in '/tmp/client.trace' on the local (client) machine: */
mysqli_debug("d:t:o,/tmp/client.trace");
?>

参见

• mysqli_dump_debug_info() 将调试信息输出到日志
• mysqli_report()别名 mysqli_driver->report_mode

can there be more documenation with a small (but working) example script on how to use this ?
Some issues (Ive seen the "same" code example in dozens of tutorials):-
( I'll use capitals for emphasis only)
QUESTION: what does D:T:O mean ? UNEXPLAINED.
QUESTION: Do we *ONLY* use these 3 lines in a self-contained script ? Does this log ALL future MYSQL commands ?
QUESTION :- Do we put that one line just
- immediately after we connect to MYSQL ?
- before we connect to MYSQL ?
- before our suspected error ?

Here are the information about debug options on mysqli_debug()
O,o:MYSQLND_DEBUG_FLUSH
A,a:MYSQLND_DEBUG_APPEND
F:MYSQLND_DEBUG_DUMP_FILE
L:MYSQLND_DEBUG_DUMP_LINE
m:MYSQLND_DEBUG_TRACE_MEMORY_CALLS
n:MYSQLND_DEBUG_DUMP_LEVEL
o:output to file
T:MYSQLND_DEBUG_DUMP_TIME
t:MYSQLND_DEBUG_DUMP_TRACE
x:MYSQLND_DEBUG_PROFILE_CALLS
f:? still investigating
For example, mysqli_debug("T:n:t:m:x:F:L:o,/tmp/client.trace");
mysqlnd will write Time, Level, trace, memory calls, profile calls, File, Line to client.trace file.
22:35:42.704501 ../mysqlnd_connection.c: 269  0:>mysqlnd_connection_init
22:35:42.704538 ../mysqlnd_driver.c:  10  1:| >mysqlnd_driver::get_connection
22:35:42.704549 ../mysqlnd_driver.c:  10  2:| | info : persistent=1
22:35:42.704558 ../mysqlnd_alloc.c:  21  2:| | >_mysqlnd_pecalloc
22:35:42.704570 ../mysqlnd_alloc.c:  23  2:| | <_mysqlnd_pecalloc (total=3 own=3 in_calls=0)
22:35:42.704602 ../mysqlnd_alloc.c:  21  2:| | >_mysqlnd_pecalloc
22:35:42.704626 ../mysqlnd_alloc.c:  23  2:| | <_mysqlnd_pecalloc (total=2 own=2 in_calls=0)
22:35:42.704650 ../mysqlnd_connection.c:  15  2:| | >mysqlnd_error_info_init
22:35:42.704675 ../mysqlnd_connection.c:  10  3:| | | >mysqlnd_error_info::reset
22:35:42.704697 ../mysqlnd_connection.c:  10  3:| | | <mysqlnd_error_info::reset (total=1 own=1 in_calls=0)
22:35:42.704725 ../mysqlnd_connection.c:  16  2:| | <mysqlnd_error_info_init (total=51 own=50 in_calls=1)
22:35:42.704744 ../mysqlnd_connection.c:  21  2:| | >mysqlnd_connection_state_init
If there is anything wrong, please let me know.

Looks like this manual could be referred to:
http://tiebing.blogspot.com.au/2011/10/cc-dbug-library.html
(I haven't tested it)