# Blockchain Inspection

**NOTE** All other debug namespace APIs **EXCEPT FOR** the following APIs are restricted with `rpc.unsafe-debug.disable` flag:

* [VM Tracing](/content/dapp/json-rpc/api-references/debug/tracing.md) APIs, however with limited functionality (only [pre-defined tracers](/content/dapp/json-rpc/api-references/debug/tracing.md#tracing-options) are allowed)
* debug\_dumpBlock, debug\_dumpStateTrie, debug\_getBlockRlp, debug\_getModifiedAccountsByHash, debug\_getModifiedAccountsByNumber, debug\_getBadBlocks, debug\_getModifiedStorageNodesByNumber
* debug\_metrics

## debug\_dumpBlock <a href="#debug_dumpblock" id="debug_dumpblock"></a>

Retrieves the state that corresponds to the block number and returns a list of accounts (including storage and code).

**NOTE**: This function correctly returns the state for a few latest, currently 4, block numbers. Retrieving older block state is restricted depending on the value set for the command-line option `--state.block-interval` (default: 128). This means that the function performs the state retrieval against only the block numbers that are multiples of state.block-interval. For example, when state.block-interval is 128, this function returns the state for the block numbers "0x0", "0x80", "0x100", "0x180", and so on. If the block number is not a multiple of state.block-interval, it returns 'missing trie node' error.

|  Client | Method Invocation                                   |
| :-----: | --------------------------------------------------- |
| Console | `debug.dumpBlock(number)`                           |
|   RPC   | `{"method": "debug_dumpBlock", "params": [number]}` |

**Parameters**

| Name                 | Type                    | Description                                                                                                                                                                                                                     |
| -------------------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| block number or hash | QUANTITY \| TAG \| HASH | Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter), or block hash. |

{% hint style="success" %}
NOTE: In versions earlier than Klaytn v1.7.0, only hex string type is available.
{% endhint %}

**Return Value**

| Type        | Description            |
| ----------- | ---------------------- |
| JSON string | The block information. |

**Example**

Console

```javascript
> debug.dumpBlock("0x80")
{
  accounts: {
    0000000000000000000000000000000000000035: {
      balance: "12800000000000000000",
      code: "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",
      codeHash: "62b00472fac99d94ccc52f5addac43d54c129cd2c6d2357c9557abea67efdec5",
      nonce: 0,
      root: "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
      storage: {}
    },
    /...(skipped).../
      codeHash: "3f34b5d7038ae652086ba4847ede2668b26a50107c5258d1412f764b942e2661",
      nonce: 1,
      root: "56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
      storage: {}
    }
  },
  root: "70383c826d1161ec2f12d799023317d8da7775dd47b8502d2d7ef646d094d3a5"
}

> debug.dumpBlock("0x81")
Error: missing trie node a573119868e0898fe5526732a079dd713c005fcbcce38dec5cae75af0378e4d3 (path )
    at web3.js:3239:20
    at web3.js:6447:15
    at web3.js:5181:36
    at <anonymous>:1:1
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_dumpBlock","params":["0x80"],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":{"root":"70383c826d1161ec2f12d799023317d8da7775dd47b8502d2d7ef646d094d3a5","accounts":{"0000000000000000000000000000000000000035":{"balance":"12800000000000000000","nonce":0,"root":"56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421","codeHash":"62b00472fac99d94ccc52f5addac43d54c129cd2c6d2357c9557abea67efdec5","code":"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","storage":{}},...(skipped)...}}}
```

## debug\_dumpStateTrie <a href="#debug_dumpstatetrie" id="debug_dumpstatetrie"></a>

Retrieves all state/storage tries of the given state root.

|  Client | Method Invocation                                       |
| :-----: | ------------------------------------------------------- |
| Console | `debug.dumpStateTrie(number)`                           |
|   RPC   | `{"method": "debug_dumpStateTrie", "params": [number]}` |

**Parameters**

| Name   | Type | Description       |
| ------ | ---- | ----------------- |
| number | int  | The block number. |

**Return Value**

| Type        | Description            |
| ----------- | ---------------------- |
| JSON string | Dump state Trie result |

**Example**

Console

```javascript
> debug.dumpStateTrie(10)
{
    root: "70383c826d1161ec2f12d799023317d8da7775dd47b8502d2d7ef646d094d3a5",
    tries: [...]
}
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_dumpStateTrie","params":["0x80"],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":{"root":"70383c826d1161ec2f12d799023317d8da7775dd47b8502d2d7ef646d094d3a5","tries":[...]}}
```

## debug\_getBlockRlp <a href="#debug_getblockrlp" id="debug_getblockrlp"></a>

Retrieves and returns the RLP-encoded block by the block number.

|  Client | Method Invocation                                     |
| :-----: | ----------------------------------------------------- |
| Console | `debug.getBlockRlp(number)`                           |
|   RPC   | `{"method": "debug_getBlockRlp", "params": [number]}` |

References: [RLP](https://github.com/ethereum/wiki/wiki/RLP)

**Parameters**

| Name                 | Type                    | Description                                                                                                                                                                                                                     |
| -------------------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| block number or hash | QUANTITY \| TAG \| HASH | Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter), or block hash. |

{% hint style="success" %}
NOTE: In versions earlier than Klaytn v1.7.0, only integer type is available.
{% endhint %}

**Return Value**

| Type   | Description            |
| ------ | ---------------------- |
| string | The RLP-encoded block. |

**Example**

Console

```javascript
> debug.getBlockRlp(100)
"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"
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_getBlockRlp","params":['200'],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":"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"}
```

## debug\_getModifiedAccountsByHash <a href="#debug_getmodifiedaccountsbyhash" id="debug_getmodifiedaccountsbyhash"></a>

Returns all accounts that have changed between the two blocks specified by their block hashes. Changes made in `endBlockHash` are included, but changes made in `startBlockHash` are not. If `endBlockHash` is not given, it returns the accounts modified in the `startBlockHash`. A change is defined as a difference in nonce, balance, code hash, or storage hash.

|  Client | Method Invocation                                                                           |
| :-----: | ------------------------------------------------------------------------------------------- |
| Console | `debug.getModifiedAccountsByNumber(startBlockHash, endBlockHash)`                           |
|   RPC   | `{"method": "debug_getModifiedAccountsByNumber", "params": [startBlockHash, endBlockHash]}` |

**Parameters**

| Name           | Type         | Description                                  |
| -------------- | ------------ | -------------------------------------------- |
| startBlockHash | 32-byte DATA | The first block hash of the range to check.  |
| endBlockHash   | 32-byte DATA | (optional) The last block hash of the range. |

**Return Value**

| Type        | Description                                             |
| ----------- | ------------------------------------------------------- |
| JSON string | The list of addresses modified between the given range. |

**Example**

Console

```javascript
> debug.getModifiedAccountsByHash("0x583a02df4222c82d4ffe5d3658d0f7ac233f4dc5de83f6430d74199038b606b6", "0x69833f0fc012dc36be910aa6909f5395cd35136dbeae29ed2170a7d4162a009c")

["0x31b93ca83b5ad17582e886c400667c6f698b8ccd", "0xb7fe15c42e66bd71835b07dc6e7daee7729f6235", "0xe31a0edb11357dba71377e625fc6174da4ef4321", "0x16b11cf9c2186a117b0da38315b42b1eaa03bbe5", "0xd3ec3c7e4cad042dbdcb6a7e0fdbc55a92276f12", "0xa4e0d726ce51572e66295756ad93206592c43a59", "0xf65e07b6626ab43ecea744803fa46bd4a89bfdb6", "0xaac56dfe44f9894d4f536cd17acfbc44bf81a843", "0x3855407fa65c4c5104648b3a9e495072df62b585", "0x61a7cbdd597848494fa85cbb76f9c63ad9c06cad", "0xa4845491cb0dad5bd6707a33c02af0d9db435c15", "0x026e8f70a26b6e5c8bec25e23869846edfdd6728", "0x3cf3e8caea91501321feee0f0692fcd98f1c6292", "0x18822790d7baf2fa6bbca6ad8baa46985abeb81b"]
```

HTTP RPC

```shell
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_getModifiedAccountsByHash","params":["0x583a02df4222c82d4ffe5d3658d0f7ac233f4dc5de83f6430d74199038b606b6", "0x69833f0fc012dc36be910aa6909f5395cd35136dbeae29ed2170a7d4162a009c"],"id":1}' https://public-en-baobab.klaytn.net

{"jsonrpc":"2.0","id":1,"result":["0x31b93ca83b5ad17582e886c400667c6f698b8ccd","0xb7fe15c42e66bd71835b07dc6e7daee7729f6235","0xe31a0edb11357dba71377e625fc6174da4ef4321","0x16b11cf9c2186a117b0da38315b42b1eaa03bbe5","0xd3ec3c7e4cad042dbdcb6a7e0fdbc55a92276f12","0xa4e0d726ce51572e66295756ad93206592c43a59","0xf65e07b6626ab43ecea744803fa46bd4a89bfdb6","0xaac56dfe44f9894d4f536cd17acfbc44bf81a843","0x3855407fa65c4c5104648b3a9e495072df62b585","0x61a7cbdd597848494fa85cbb76f9c63ad9c06cad","0xa4845491cb0dad5bd6707a33c02af0d9db435c15","0x026e8f70a26b6e5c8bec25e23869846edfdd6728","0x3cf3e8caea91501321feee0f0692fcd98f1c6292","0x18822790d7baf2fa6bbca6ad8baa46985abeb81b"]}
```

## debug\_getModifiedAccountsByNumber <a href="#debug_getmodifiedaccountsbynumber" id="debug_getmodifiedaccountsbynumber"></a>

Returns all accounts that have changed between the two blocks specified by their block numbers. Changes made in `endBlockNum` are included, but changes made in `startBlockNum` are not. If `endBlockNum` is not given, it returns the accounts modified in the `startBlockNum`. A change is defined as a difference in nonce, balance, code hash, or storage hash.

|  Client | Method Invocation                                                                         |
| :-----: | ----------------------------------------------------------------------------------------- |
| Console | `debug.getModifiedAccountsByNumber(startBlockNum, endBlockNum)`                           |
|   RPC   | `{"method": "debug_getModifiedAccountsByNumber", "params": [startBlockNum, endBlockNum]}` |

**Parameters**

| Name          | Type | Description                                    |
| ------------- | ---- | ---------------------------------------------- |
| startBlockNum | int  | The first block number of the range to check.  |
| endBlockNum   | int  | (optional) The last block number of the range. |

**Return Value**

| Type        | Description                                             |
| ----------- | ------------------------------------------------------- |
| JSON string | The list of addresses modified between the given range. |

**Example**

Console

```javascript
> debug.getModifiedAccountsByNumber(171904, 172160)
["0x31b93ca83b5ad17582e886c400667c6f698b8ccd", "0xb7fe15c42e66bd71835b07dc6e7daee7729f6235", "0xe31a0edb11357dba71377e625fc6174da4ef4321", "0x16b11cf9c2186a117b0da38315b42b1eaa03bbe5", "0xd3ec3c7e4cad042dbdcb6a7e0fdbc55a92276f12", "0xa4e0d726ce51572e66295756ad93206592c43a59", "0xf65e07b6626ab43ecea744803fa46bd4a89bfdb6", "0xaac56dfe44f9894d4f536cd17acfbc44bf81a843", "0x3855407fa65c4c5104648b3a9e495072df62b585", "0x61a7cbdd597848494fa85cbb76f9c63ad9c06cad", "0xa4845491cb0dad5bd6707a33c02af0d9db435c15", "0x026e8f70a26b6e5c8bec25e23869846edfdd6728", "0x3cf3e8caea91501321feee0f0692fcd98f1c6292", "0x18822790d7baf2fa6bbca6ad8baa46985abeb81b"]
```

HTTP RPC

```shell
curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_getModifiedAccountsByNumber","params":[171904, 172160],"id":1}' https://public-en-baobab.klaytn.net

{"jsonrpc":"2.0","id":1,"result":["0x31b93ca83b5ad17582e886c400667c6f698b8ccd","0xb7fe15c42e66bd71835b07dc6e7daee7729f6235","0xe31a0edb11357dba71377e625fc6174da4ef4321","0x16b11cf9c2186a117b0da38315b42b1eaa03bbe5","0xd3ec3c7e4cad042dbdcb6a7e0fdbc55a92276f12","0xa4e0d726ce51572e66295756ad93206592c43a59","0xf65e07b6626ab43ecea744803fa46bd4a89bfdb6","0xaac56dfe44f9894d4f536cd17acfbc44bf81a843","0x3855407fa65c4c5104648b3a9e495072df62b585","0x61a7cbdd597848494fa85cbb76f9c63ad9c06cad","0xa4845491cb0dad5bd6707a33c02af0d9db435c15","0x026e8f70a26b6e5c8bec25e23869846edfdd6728","0x3cf3e8caea91501321feee0f0692fcd98f1c6292","0x18822790d7baf2fa6bbca6ad8baa46985abeb81b"]}
```

## debug\_preimage <a href="#debug_preimage" id="debug_preimage"></a>

Returns the preimage for a sha3 hash, if known.

|  Client | Method Invocation                                |
| :-----: | ------------------------------------------------ |
| Console | `debug.preimage(hash)`                           |
|   RPC   | `{"method": "debug_preimage", "params": [hash]}` |

**Parameters**

| Name | Type   | Description |
| ---- | ------ | ----------- |
| hash | string | sha3 hash.  |

**Return Value**

| Name     | Type   | Description               |
| -------- | ------ | ------------------------- |
| preimage | string | Preimage for a sha3 hash. |

**Example**

Console

```javascript
> debug.preimage("0xaf953a2d01f55cfe080c0c94150a60105e8ac3d51153058a1f03dd239dd08586")
"0xdd738d9a7d987a98798123b2322d389470328420bb3d84023a8405a5523cc532235ba325235243242cb9a4758609a8604 ...  98bbd743053d0cbadaaccd4865cc0348685460ada874506ad984506ad80458ad69038fd6f908340fd9af68faf903760"
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_preimage","params":["0xaf953a2d01f55cfe080c0c94150a60105e8ac3d51153058a1f03dd239dd08586"],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":"0xaf953a2d01f55cfe080c0c94150a60105e8ac3d51153058a1f03dd239dd08586")
"0xdd738d9a7d987a98798123b2322d389470328420bb3d84023a8405a5523cc532235ba325235243242cb9a4758609a8604 ...  98bbd743053d0cbadaaccd4865cc0348685460ada874506ad984506ad80458ad69038fd6f908340fd9af68faf903760"}
```

## debug\_getBadBlocks <a href="#debug_getbadblocks" id="debug_getbadblocks"></a>

Returns a list of the last 'bad blocks' that the client has seen on the network.

|  Client | Method Invocation                                |
| :-----: | ------------------------------------------------ |
| Console | `debug.getBadBlocks()`                           |
|   RPC   | `{"method": "debug_getBadBlocks", "params": []}` |

**Parameters**

None

**Return Value**

| Name     | Type | Description               |
| -------- | ---- | ------------------------- |
| badBlock | JSON | JSON list of block-hashes |

**Example**

Console

```javascript
> debug.getBadBlocks()
[]
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_getBadBlocks","params":[],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":[]}
```

## debug\_printBlock <a href="#debug_printblock" id="debug_printblock"></a>

Retrieves a block and returns its pretty printed form.

|  Client | Method Invocation                                    |
| :-----: | ---------------------------------------------------- |
| Console | `debug.printBlock(number)`                           |
|   RPC   | `{"method": "debug_printBlock", "params": [number]}` |

**Parameters**

| Name                 | Type                    | Description                                                                                                                                                                                                                     |
| -------------------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| block number or hash | QUANTITY \| TAG \| HASH | Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter), or block hash. |

{% hint style="success" %}
NOTE: In versions earlier than Klaytn v1.7.0, only integer type is available.
{% endhint %}

**Return Value**

| Type   | Description             |
| ------ | ----------------------- |
| string | Dump of a block struct. |

**Example**

Console

```javascript
> debug.printBlock(65120)
"(*types.Block)(0xc436fad3b0)(Block(#65120): Size: 2.95 kB {\nMinerHash: 7a5f8d37d34be6d9d19c5f161756d607da62227bb725ddb2f372682d7a9f1445\nHeader(e96d6477acfeba8ba865c315020471dcf751aa1bddca77f469334ab0492d218f):\n[\n\tParentHash:      e768b5b7eeb1005fe130c26da744d47e042e9227cee675fa70c89ede38653aea\n\tCoinbase:         0000000000000000000000000000000000000000\n\tRewardbase:       0000000000000000000000000000000000000000\n\tRoot: ... 0xc3be927ae5c0c48a0c83a1dbdf2df737c4a708eb6dae0ccb4a7eb042ea0a6ebf\n\tS:       0x53d8bed6357f88c8bab1f3d83942aa53c14269e58016e284656b12996a5d759a\n\tHex:      f863829d9280825208949619a83fcefc5647736cfd28845fcc4f716ff53b8080820fe7a0c3be927ae5c0c48a0c83a1dbdf2df737c4a708eb6dae0ccb4a7eb042ea0a6ebfa053d8bed6357f88c8bab1f3d83942aa53c14269e58016e284656b12996a5d759a\n]\n}\n)\n"

```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_printBlock","params":[65120],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":"(*types.Block)(0xc4355b05a0)(Block(#65120): Size: 2.95 kB {\nMinerHash: 7a5f8d37d34be6d9d19c5f161756d607da62227bb725ddb2f372682d7a9f1445\nHeader(e96d6477acfeba8ba865c315020471dcf751aa1bddca77f469334ab0492d218f):\n[\n\tParentHash:       e768b5b7eeb1005fe130c26da744d47e042e9227cee675fa70c89ede38653aea\n\tCoinbase:         0000000000000000000000000000000000000000\n\tRewardbase:  ... 0000000000000000000000000000000000000000\n\tRoot:             4fd68a8f550cbd9ad665bc1a8021882ced5e1859fd9e28a48cb2910532b6ef27\n\tTxSha:            e3dbb8245038adcdc849de54af1d05f0c36c4c20d2710e31d525bd012d20a193\n\tReceiptSha:       212d4f453a897e2a486c86a4b120c1a850e89753865fe7f1aafa4"}
```

## debug\_setHead <a href="#debug_sethead" id="debug_sethead"></a>

Sets the current head of the local chain by block number.

**NOTE**: This is a destructive action and may severely damage your chain. Use with *extreme* caution.

|  Client | Method Invocation                                 |
| :-----: | ------------------------------------------------- |
| Console | `debug.setHead(number)`                           |
|   RPC   | `{"method": "debug_setHead", "params": [number]}` |

**Parameters**

| Name   | Type            | Description                                                                                                                                                                                                      |
| ------ | --------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| number | QUANTITY \| TAG | Integer or hexadecimal block number, or the string `"earliest"`, `"latest"` or `"pending"` as in the [default block parameter](/content/dapp/json-rpc/api-references/klay/block.md#the-default-block-parameter). |

**Return Value**

None

**Example**

Console

```javascript
> debug.setHead("0x100")
null
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_setHead","params":["0x100"],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":null}
```

## debug\_seedHash <a href="#debug_seedhash" id="debug_seedhash"></a>

Retrieves the seed hash of a block.

|  Client | Method Invocation                                  |
| :-----: | -------------------------------------------------- |
| Console | `debug.seedHash(number)`                           |
|   RPC   | `{"method": "debug_seedHash", "params": [number]}` |

**Parameters**

| Name   | Type   | Description       |
| ------ | ------ | ----------------- |
| number | uint64 | The block number. |

**Return Value**

| Name     | Type   | Description          |
| -------- | ------ | -------------------- |
| seedHash | string | The block seed hash. |

**Example**

Console

```javascript
> debug.seedHash(100)
"0x0000000000000000000000000000000000000000000000000000000000000000"
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_seedHash","params":[100],"id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":"0x0000000000000000000000000000000000000000000000000000000000000000"}
```

## debug\_startWarmUp <a href="#debug_startwarmup" id="debug_startwarmup"></a>

The `startWarmUp` iterates the latest state trie to warm-up the trie cache. The iteration will be automatically stopped if 90% of the trie cache is full. The method returns an error if it fails in starting a warm-up, or `null` if it successfully has started it.

|  Client | Method invocation                 |
| :-----: | --------------------------------- |
| Console | `debug.startWarmUp()`             |
|   RPC   | `{"method": "debug_startWarmUp"}` |

**Parameters**

None

**Return Value**

| Type  | Description                                         |
| ----- | --------------------------------------------------- |
| Error | `null` if a warm-up is started, or an error if not. |

**Example**

Console

```javascript
> debug.startWarmUp()
null
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_startWarmUp","id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":null}
```

## debug\_startContractWarmUp <a href="#debug_startcontractwarmup" id="debug_startcontractwarmup"></a>

The `startContractWarmUp` iterates the latest storage trie of the given contract address to warm-up the trie cache. The iteration will be automatically stopped if 90% of the trie cache is full. The method returns an error if it fails in starting a warm-up or the given address is not a contract address, or `null` if it successfully has started it.

|  Client | Method invocation                                              |
| :-----: | -------------------------------------------------------------- |
| Console | `debug.startContractWarmUp(address)`                           |
|   RPC   | `{"method": "debug_startContractWarmUp", "params": [address]}` |

**Parameters**

| Type         | Description      |
| ------------ | ---------------- |
| 20-byte DATA | Contract address |

**Return Value**

| Type  | Description                                         |
| ----- | --------------------------------------------------- |
| Error | `null` if a warm-up is started, or an error if not. |

**Example**

Console

```javascript
> debug.startContractWarmUp("0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b")
null
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_startContractWarmUp", "params":["0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b"], "id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":null}
```

## debug\_stopWarmUp <a href="#debug_stopwarmup" id="debug_stopwarmup"></a>

The `stopWarmUp` stops the currently running warm-up. This method takes no parameters, and returns `null` or an error depending on a warm-up was stopped or not.

|  Client | Method invocation          |
| :-----: | -------------------------- |
| Console | `debug.stopWarmUp()`       |
|   RPC   | `{"method": "stopWarmUp"}` |

**Parameters**

None

**Return Value**

| Type  | Description                                         |
| ----- | --------------------------------------------------- |
| Error | `null` if a warm-up is stopped, or an error if not. |

**Example**

Console

```javascript
> debug.stopWarmUp()
true
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_stopWarmUp","id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":null}
```

## debug\_startCollectingTrieStats <a href="#debug_startcollectingtriestats" id="debug_startcollectingtriestats"></a>

The `startCollectingTrieStats` iterates the latest state or storage trie to collect trie statistics. It collects storage trie statistics of the contract in the given address. If an empty address(="0x00...00") is given, it collects statistics of the whole state trie. Statistics will be logged every minute before end, containing overall and depth-by-depth information. The method returns an error if it fails in starting a task, or `null` if it successfully has started it.

|  Client | Method invocation                                                   |
| :-----: | ------------------------------------------------------------------- |
| Console | `debug.startCollectingTrieStats(address)`                           |
|   RPC   | `{"method": "debug_startCollectingTrieStats", "params": [address]}` |

**Parameters**

| Type         | Description      |
| ------------ | ---------------- |
| 20-byte DATA | Contract address |

**Return Value**

| Type  | Description                                                               |
| ----- | ------------------------------------------------------------------------- |
| Error | `null` if collecting trie statistics task is started, or an error if not. |

**Example**

Console

```javascript
// empty address to collect whole state trie statistics
> debug.startCollectingTrieStats("0x0000000000000000000000000000000000000000")
null
// contract address to collect storage trie statistics
> debug.startCollectingTrieStats("0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b")
null
```

HTTP RPC

```shell
$ curl -H "Content-Type: application/json" --data '{"jsonrpc":"2.0","method":"debug_startCollectingTrieStats", "params":["0xa94f5374fce5edbc8e2a8697c15331677e6ebf0b"], "id":1}' https://public-en-baobab.klaytn.net
{"jsonrpc":"2.0","id":1,"result":null}
```

Log

```
INFO[03/10,12:03:12 +09] [5] Started collecting trie statistics        blockNum=1491072 root=0x64af12b6374b92f6db457fa1b98fe9522d9f36ba352e3c4e01cdb75f001e8264 len(children)=16
...
INFO[03/10,12:03:12 +09] [5] Finished collecting trie statistics       elapsed=95.152412ms numNodes=133036 numLeafNodes=95948 maxDepth=9
INFO[03/10,12:03:12 +09] [5] number of leaf nodes in a depth           depth=5 numNodes=22098
INFO[03/10,12:03:12 +09] [5] number of leaf nodes in a depth           depth=6 numNodes=65309
INFO[03/10,12:03:12 +09] [5] number of leaf nodes in a depth           depth=7 numNodes=8083
INFO[03/10,12:03:12 +09] [5] number of leaf nodes in a depth           depth=8 numNodes=456
INFO[03/10,12:03:12 +09] [5] number of leaf nodes in a depth           depth=9 numNodes=2
```


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