(PHP 5, PHP 7, PHP 8)
mysqli::debug -- mysqli_debug — Performs debugging operations
Object-oriented style
$options): boolProcedural style
$options): boolPerforms debugging operations using the Fred Fish debugging library.
optionsA string representing the debugging operation to perform
        The debug control string is a sequence of colon separated fields as follows:
        <field_1>:<field_2>:<field_N>
, and comma separated list of modifiers:
        flag[,modifier,modifier,...,modifier]
      
| optioncharacter | Description | 
|---|---|
| O | MYSQLND_DEBUG_FLUSH | 
| A/a | MYSQLND_DEBUG_APPEND | 
| F | MYSQLND_DEBUG_DUMP_FILE | 
| i | MYSQLND_DEBUG_DUMP_PID | 
| 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 | 
   Returns true.
  
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");
?>
Note:
To use the mysqli_debug() function you must compile the MySQL client library to support debugging.