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 ..."}