Runtime Debugging

NOTE All other debug namespace APIs EXCEPT FOR the following APIs are restricted with rpc.unsafe-debug.disable flag:
​VM Tracing APIs, however with limited functionality (only pre-defined tracers are allowed)
debug_dumpBlock, debug_dumpStateTrie, debug_getBlockRlp, debug_getModifiedAccountsByHash, debug_getModifiedAccountsByNumber, debug_getBadBlocks, debug_getModifiedStorageNodesByNumber
debug_metrics
debug_freeOSMemory
Returns unused memory to the OS.
Client
Method Invocation
Console
debug.freeOSMemory()
RPC
{"method": "debug_freeOSMemory"}
Parameters
None
Return Value
None
Example
Console
> debug.freeOSMemory()
null
HTTP RPC
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_freeOSMemory","id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":null}
debug_gcStats
Returns GC statistics.
Client
Method Invocation
Console
debug.gcStats()
RPC
{"method": "debug_gcStats", "params": []}
Parameters
None
Return Value
See https://golang.org/pkg/runtime/debug/#GCStats for information about the fields of the returned object.
Example
Console
> debug.gcStats()
{
  LastGC: "2018-10-08T14:27:34.030659164Z",
  NumGC: 40,
  Pause: [4582691, 2863122, 1578188, 459447, 197699, 1688008, 678298, 117924, 6871625, 298523, 1281135, 616022, 2513029, 265029, 704801, 685752, 383625, 677657, 1135878, 1730593, 603201, 2667691, 1901266, 1035406, 1624233, 1112526, 397637, 158158, 596931, 2675197, 4421722, 745039, 847417, 4423680, 653433, 281915, 605418, 8127664, 138283, 1810200],
  PauseEnd: ["2018-10-08T14:27:34.030659164Z", "2018-10-08T14:25:34.032422737Z", "2018-10-08T14:23:34.015065773Z", "2018-10-08T14:21:34.031893519Z", "2018-10-08T14:19:33.791324489Z", "2018-10-08T14:19:01.028883257Z", "2018-10-08T14:17:01.054270356Z", "2018-10-08T14:15:01.032846304Z", "2018-10-08T14:13:01.07313761Z", "2018-10-08T14:11:01.042653342Z", "2018-10-08T14:09:01.034458873Z", "2018-10-08T14:07:01.022701083Z", "2018-10-08T14:05:01.046456415Z", "2018-10-08T14:03:01.030075376Z", "2018-10-08T14:01:01.027838941Z", "2018-10-08T13:59:01.033363592Z", "2018-10-08T13:57:01.032853252Z", "2018-10-08T13:55:01.06825876Z", "2018-10-08T13:53:01.071426346Z", "2018-10-08T13:51:01.099618831Z", "2018-10-08T13:49:01.016314071Z", "2018-10-08T13:47:01.031721975Z", "2018-10-08T13:45:01.029069094Z", "2018-10-08T13:43:01.026156953Z", "2018-10-08T13:41:01.019240344Z", "2018-10-08T13:39:01.026699743Z", "2018-10-08T13:37:01.02642045Z", "2018-10-08T13:35:00.997556262Z", "2018-10-08T13:33:01.023605742Z", "2018-10-08T13:31:01.025436347Z", "2018-10-08T13:29:01.024808072Z", "2018-10-08T13:27:01.01508169Z", "2018-10-08T13:25:01.023461518Z", "2018-10-08T13:23:01.0144789Z", "2018-10-08T13:21:01.022121597Z", "2018-10-08T13:19:30.748905748Z", "2018-10-08T13:19:29.588457028Z", "2018-10-08T13:19:29.461820065Z", "2018-10-08T13:19:29.436792038Z", "2018-10-08T13:19:29.408990947Z"],
  PauseQuantiles: null,
  PauseTotal: 64156063
}
HTTP RPC
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_gcStats","params":[],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":{"LastGC":"2018-10-15T00:42:08.2787037Z","NumGC":14,"PauseTotal":292805500,"Pause":[3384700,60164200,259500,354600,62331200,241700,29701500,4868200,8242800,35177700,27621100,12647400,38250100,9560800],"PauseEnd":["2018-10-15T00:42:08.2787037Z","2018-10-15T00:40:19.3302813Z","2018-10-15T00:38:41.2202755Z","2018-10-15T00:36:41.2785669Z","2018-10-15T00:36:18.3196569Z","2018-10-15T00:34:48.2073609Z","2018-10-15T00:33:01.3309817Z","2018-10-15T00:31:28.3465898Z","2018-10-15T00:30:05.4245261Z","2018-10-15T00:28:58.6377593Z","2018-10-15T00:27:55.315809Z","2018-10-15T00:27:45.075085Z","2018-10-15T00:27:44.9164574Z","2018-10-15T00:27:44.8406572Z"],"PauseQuantiles":null}}
debug_memStats
Returns detailed runtime memory statistics.
Client
Method Invocation
Console
debug.memStats()
RPC
{"method": "debug_memStats", "params": []}
Parameters
None
Return Value
See https://golang.org/pkg/runtime/#MemStats for information about the fields of the returned object.
Example
Console
> debug.memStats()
{
  Alloc: 132244280,
  BuckHashSys: 1922010,
  BySize: [{
      Frees: 0,
      Mallocs: 0,
      Size: 0
  }, {
      Frees: 496599,
      Mallocs: 499580,
      Size: 8
  },
  ...
  StackSys: 1195456,
  Sys: 107909880,
  TotalAlloc: 2105944960
}
HTTP RPC
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_memStats","params":[],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":{"Alloc":265525152,"TotalAlloc":3548997112,"Sys":756177144,"Lookups":2165,"Mallocs":25572268,"Frees":24933943,
...
"Frees":36},{"Size":16384,"Mallocs":123,"Frees":122},{"Size":18432,"Mallocs":11,"Frees":3},{"Size":19072,"Mallocs":2,"Frees":1}]}}
debug_metrics
Retrieves all the known system metrics collected by the node.
Client
Method Invocation
Console
debug.metrics(raw)
RPC
{"method": "debug_metrics", "params": [raw]}
Parameters
Name
Type
Description
raw
bool
true If raw data is output as it is, false If not
Return Value
Type
Description
JSON string
The structured metrics collected by the node.
Example
Console
> debug.metrics(true)
debug.metrics(true)
{
...
chain: {
  inserts: {
    AvgRate01Min: 0.9999999999999988,
    AvgRate05Min: 0.9999950225324217,
    AvgRate15Min: 0.9963720514881304,
    MeanRate: 0.9936029165254054,
    Overall: 5122,
    Percentiles: {
      20: 6266950,
      5: 5950439.75,
      50: 6682947,
      80: 7255046,
      95: 9365905.249999994
    }
  }
},
...
system: {
  disk: {
    readcount: {
      AvgRate01Min: 56.44435697476854,
      AvgRate05Min: 55.584662531212246,
      AvgRate15Min: 55.34119664885956,
      MeanRate: 47.632311872105376,
      Overall: 245543
    },
    readdata: {
      AvgRate01Min: 12317.25061664709,
      AvgRate05Min: 12166.068673100728,
      AvgRate15Min: 12672.361505927352,
      MeanRate: 15647.98456421136,
      Overall: 80664847
    },
    writecount: {
      AvgRate01Min: 181.87825585990814,
      AvgRate05Min: 179.42841085089034,
      AvgRate15Min: 177.29930723824663,
      MeanRate: 145.6261462083422,
      Overall: 750698
    },
    writedata: {
      AvgRate01Min: 24683.661802447285,
      AvgRate05Min: 24302.28523786675,
      AvgRate15Min: 24142.37073674183,
      MeanRate: 25207.081062276873,
      Overall: 129941675
    }
  }
}
HTTP RPC
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_metrics","params":[true],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":{"blockchain":{"block":{"tx":{"counter":{"Overall":98307},"rate":{"AvgRate01Min":19.99999999999893,"AvgRate05Min":19.999669059400787,"AvgRate15Min":19.91097896398045,"MeanRate":16.321034565305364,"Overall":98307}}},"head":{"blocknumber":"Unknown metric type"}},"bridgeTxpool":{"refuse":{"Overall":0}}, ...{"AvgRate01Min":0.9999999999999988,"AvgRate05Min":0.9999997215208508,"AvgRate15Min":0.9986124269288207,"MeanRate":0.9946322927570416,"Overall":5991,"Percentiles":{"20":6229668,"5":5986862.3,"50":6585653,"80":6864326.2,"95":7486187.249999999}}}}
debug_setGCPercent
Sets the garbage collection target percentage. It returns the previous setting. A negative value disables GC.
Parameters
Name
Type
Description
Percent
integer
Garbage collection target percentage.
Return Value
Type
Description
integer
Previous garbage collection target percentage.
Example Console
> debug.setGCPercent(50)
100
> debug.setGCPercent(70)
50
> debug.setGCPercent(100)
70
HTTP RPC
curl -X POST -H "Content-Type: application/json" --data '{"jsonrpc":"2.0", "method":"debug_setGCPercent", "params":[100],"id":73}' https://public-en-baobab.klaytn.net
​
{
  "jsonrpc":"2.0",
  "id":73,
  "result":70
}
debug_stacks
Returns a printed representation of the stacks of all goroutines.
Client
Method Invocation
Console
debug.stacks()
RPC
{"method": "debug_stacks", "params": []}
Parameters
None
Return Value
Type
Description
string
The stack information of all goroutines.
Example
Console
> debug.stacks()
goroutine 163577 [running]:
/api/debug.(*HandlerT).Stacks(0xc4200a4780, 0x0, 0x0)
	/klaytn/build/_workspace/src/github.com/klaytn/klaytn/api/debug/api.go:173 +0x74
reflect.Value.call(0xc4213a80c0, 0xc42134d1f0, 0x13, 0xf050ec, 0x4, 0xc4233957a0, 0x1, 0x1, 0x474401, 0xc4233956c8, ...)
...
HTTP RPC
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_stacks","params":[],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":"goroutine 76176 [running]:\ngithub.com/klaytn/klaytn/api/debug.(*HandlerT).Stacks(0xc0002ce050, 0x0, 0x0)\n\t/private/tmp/klaytn-20181001-13887-zbyv2z/build/_workspace/src/github.com/klaytn/klaytn/api/debug/api.go:173 +0x74\nreflect.Value.call(0xc01867c660, 0xc000231bd8, 0x13, 0x4b26ca7, 0x4, 0xc008d8b7c0, 0x1, 0x1, 0x30, 0xc0323211d0 ..."}

Client	Method Invocation
Console	`debug.freeOSMemory()`
RPC	`{"method": "debug_freeOSMemory"}`

Client	Method Invocation
Console	`debug.gcStats()`
RPC	`{"method": "debug_gcStats", "params": []}`

Client	Method Invocation
Console	`debug.memStats()`
RPC	`{"method": "debug_memStats", "params": []}`

Client	Method Invocation
Console	`debug.metrics(raw)`
RPC	`{"method": "debug_metrics", "params": [raw]}`

Name	Type	Description
raw	bool	`true` If raw data is output as it is, `false` If not

Type	Description
JSON string	The structured metrics collected by the node.

Name	Type	Description
Percent	integer	Garbage collection target percentage.

Type	Description
integer	Previous garbage collection target percentage.

Client	Method Invocation
Console	`debug.stacks()`
RPC	`{"method": "debug_stacks", "params": []}`

Type	Description
string	The stack information of all goroutines.

Runtime Tracing

VM Tracing

Last modified 4mo ago