{{about|the command that runs time profiler and function trace|the performance profiler|Commands/perf|the jvm profiler|Commands/jfr|other uses of "debug"|Debug}}
{{exclusive|java}}
{{Infobox command
|name=debug
|oplevel=3
}}

Starts or stops a time profiler session. Gets more detailed information of function execution.

== Syntax ==
<code>debug start</code>
: Starts a new debug time profiler session.
<code>debug stop</code>
: Stops the active debug time profiler session.
<code>debug function <name></code>
: Used the same way as [[Commands/function|/function]] to get more detailed information of commands' execution. Could not be called directly or indirectly by {{cmd|return run}} or another {{cmd|debug function}}.

== Arguments ==
{{argument|name|function}}
: {{arg desc|je=function}}

== Result ==
{{Result table|onlyje=1}}
{{Result table|The command is incomplete, or any argument is not specified correctly.|unparseable}}
{{Result table|cmd=/debug start|A debug profiling session has already been started.|fail}}
{{Result table|cmd=/debug stop|There's no debug profiling session running.}}
{{Result table|cmd=/debug function|The specified functions or function tags do not exist.}}
{{Result table|cmd=/debug function|This command execution is caused by {{cmd|return run}} or another {{cmd|debug function}}.}}
{{Result table|cmd=|succeed}}
{{Result table}}

== Output ==
{{Output table}}
{{Output table|edition=je|On fail|N/A|0|0}}
{{Output table|cmd=/debug start|On success|N/A|1|0}}
{{Output table|cmd=/debug stop|On success|N/A|1|the average tps (ticks per second) during debug profiling}}
{{Output table|cmd=/debug function|On success|N/A|1|the total number of commands in the functions}}
{{Output table}}

== File structure ==
=== Function trace ===
When using {{cmd|debug function|link=none}}, a txt file titled '''debug-trace-yyyy-MM-dd_HH.mm.ss.txt''' is created in <samp>.minecraft/debug</samp>.

In this file,
*<code>[C] <command></code> means the <code><command></code> is executed.
*<code>[M] <message></code> means a message is returned.
*<code>[E] <message></code> means a failure message is returned.
*<code>[R = <num>] <command></code> means the <code><command></code> returns a '''brigadier return value'''.
*<code>[C] <command> -> <num></code> means the <code><command></code> is executed and returns a '''brigadier return value'''.
*<code>[F] <function> size=<num></code> means a function is called.

For most of commands, the '''brigadier return value''' is equal to the result value that can be stored with <code>/execute store result</code>.

But for <code>/execute ...</code> '''with one or more of the following subcommands''', each branch returns its success value as its '''brigadier return value''':
* <code>... if ...</code> (not at the end)
* <code>... unless ...</code> (not at the end)
* <code>... as <targets> ...</code>
* <code>... at <targets> ...</code>
* <code>... positioned as <targets> ...</code>
* <code>... rotated as <targets> ...</code>
* <code>... facing entity <targets> <anchor> ...</code>

Some commands like <code>/return</code> and <code>/function</code> has no brigadier return value。

=== Profile result ===
{{Outdated feature|section=1}}
When using {{cmd|debug stop|link=none}}, a txt file titled '''profile-results-yyyy-MM-dd_HH.mm.ss.txt''' is created in <samp>.minecraft/debug</samp>, which includes the result of profile dump.
=== Report ===
{{Outdated feature|section=1}}
When using {{cmd|debug report|link=none}}, a ZIP file is created with in <samp>.minecraft/debug/profiling</samp> the following structure:
<div class=treeview>
* '''debug-report-yyyy-MM-dd_HH.mm.ss.zip'''
** '''levels'''
*** '''minecraft''' or '''<other custom namespaces>'''
**** '''overworld''' or '''the_end''' or '''the_nether''' or '''<other custom dimensions>'''
***** '''block_entities.csv''': Contains a list of [[block entities]] in the world in the format <code>x,y,z,type</code>.
***** '''chunks.csv''': Contains a list of chunk information in the format {{cd|x,z,level,in_memory,status,full_status,accessible_ready,ticking_ready,entity_ticking_ready,ticket,spawning,entity_count,block_entity_count}}.
***** '''entities.csv''': Contains a list of [[entities]] in the world in the format {{cd|x,y,z,uuid,type,alive,custom_name}}.
***** '''example_crash.txt''': An example crash file.
***** '''stats.txt''': Contains some stats.
** '''classpath.txt''': Contains the file paths of the external jars ''Minecraft'' uses.
** '''example_crash.txt''': An example crash file.
** '''gamerules.txt''': A plain text file containing a list of [[game rule]]s and their values (<code><gamerule>=<value></code>).
** '''stats.txt''': Contains some stats.
** '''threads.txt''': All running threads.
</div>

== History ==
{{HistoryTable
|{{HistoryLine|java}}
|{{HistoryLine||1.3.1|dev=12w27a|Added {{cmd|debug|link=none}}.}}
|{{HistoryLine||1.8|dev=14w31a|{{cmd|debug|link=none}} can now be run in single-player.
|Added {{cmd|debug chunk|link=none}}.}}
|{{HistoryLine||1.8.1|dev=pre1|Removed {{cmd|debug chunk|link=none}}.}}
|{{HistoryLine||1.13|dev=18w03a|Added commands to the profiler.}}
|{{HistoryLine||1.14.4|dev=pre1|Added {{cmd|debug report|link=none}}, used to get more detailed information while debugging performance.}}
|{{HistoryLine||1.17|dev=21w15a|Added {{cmd|debug function|link=none}}.}}
|{{HistoryLine|||dev=Pre-release 1|Removed {{cmd|debug report|link=none}}. Replaced by F3+L and {{cmd|perf|link=none}}.}}
|{{HistoryLine||1.20.3|dev=23w41a|Now the result value of {{cmd|debug function|link=none}} is the total number of commands in the functions.
|Now {{cmd|debug function|link=none}} cannot be called by {{cmd|debug function|link=none}}.}}
|{{HistoryLine|||dev=23w44a|Now {{cmd|debug function|link=none}} cannot be called by {{cmd|return run}}.}}
}}

== Navigation ==
{{Navbox commands}}

[[de:Befehl/debug]]
[[ja:コマンド/debug]]
[[pt:Comandos/debug]]
[[ru:Команды консоли/debug]]
[[zh:命令/debug]]