debug
The debug API gives you access to several non-standard RPC methods, which will allow you to inspect, debug and set certain debugging flags during runtime.
debug_accountRange
debug_accountRange
Enumerates all accounts at a given block with paging capability. maxResults are returned in the page and the items have keys that come after the start key (hashed address).
If incompletes is false, then accounts for which the key preimage (i.e: the address) doesn't exist in db are skipped. NB: geth by default does not store preimages.
Console
debug.accountRange(blockNrOrHash, start, maxResults, nocode, nostorage, incompletes)
RPC
{"method": "debug_accountRange", "params": [blockNrOrHash, start, maxResults, nocode, nostorage, incompletes]}
debug_backtraceAt
debug_backtraceAt
Sets the logging backtrace location. When a backtrace location is set and a log message is emitted at that location, the stack of the goroutine executing the log statement will be printed to stderr.
The location is specified as <filename>:<line>.
Console
debug.backtraceAt(string)
RPC
{"method": "debug_backtraceAt", "params": [string]}
Example:
debug_blockProfile
debug_blockProfile
Turns on block profiling for the given duration and writes profile data to disk. It uses a profile rate of 1 for most accurate information. If a different rate is desired, set the rate and write the profile manually using debug_writeBlockProfile.
Console
debug.blockProfile(file, seconds)
RPC
{"method": "debug_blockProfile", "params": [string, number]}
debug_chaindbCompact
debug_chaindbCompact
Flattens the entire key-value database into a single level, removing all unused slots and merging all keys.
Console
debug.chaindbCompact()
RPC
{"method": "debug_chaindbCompact", "params": []}
debug_chaindbProperty
debug_chaindbProperty
Returns leveldb properties of the key-value database.
Console
debug.chaindbProperty(property string)
RPC
{"method": "debug_chaindbProperty", "params": [property]}
debug_cpuProfile
debug_cpuProfile
Turns on CPU profiling for the given duration and writes profile data to disk.
Console
debug.cpuProfile(file, seconds)
RPC
{"method": "debug_cpuProfile", "params": [string, number]}
debug_dbAncient
debug_dbAncient
Retrieves an ancient binary blob from the freezer. The freezer is a collection of append-only immutable files. The first argument kind specifies which table to look up data from. The list of all table kinds are as follows:
headers: block headers
hashes: canonical hash table (block number -> block hash)
bodies: block bodies
receipts: block receipts
diffs: total difficulty table (block number -> td)
Console
debug.dbAncient(kind string, number uint64)
RPC
{"method": "debug_dbAncient", "params": [string, number]}
debug_dbAncients
debug_dbAncients
Returns the number of ancient items in the ancient store.
Console
debug.dbAncients()
RPC
{"method": "debug_dbAncients"}
debug_dbGet
debug_dbGet
Returns the raw value of a key stored in the database.
Console
debug.dbGet(key string)
RPC
{"method": "debug_dbGet", "params": [key]}
debug_dumpBlock
debug_dumpBlock
Retrieves the state that corresponds to the block number and returns a list of accounts (including storage and code).
Go
debug.DumpBlock(number uint64) (state.World, error)
Console
debug.traceBlockByHash(number, [options])
RPC
{"method": "debug_dumpBlock", "params": [number]}
Example:
debug_freeOSMemory
debug_freeOSMemory
Forces garbage collection
Go
debug.FreeOSMemory()
Console
debug.freeOSMemory()
RPC
{"method": "debug_freeOSMemory", "params": []}
debug_freezeClient
debug_freezeClient
Forces a temporary client freeze, normally when the server is overloaded. Available as part of LES light server.
Console
debug.freezeClient(node string)
RPC
{"method": "debug_freezeClient", "params": [node]}
debug_gcStats
debug_gcStats
Returns garbage collection statistics.
See https://golang.org/pkg/runtime/debug/#GCStats for information about the fields of the returned object.
Console
debug.gcStats()
RPC
{"method": "debug_gcStats", "params": []}
debug_getAccessibleState
debug_getAccessibleState
Returns the first number where the node has accessible state on disk. This is the post-state of that block and the pre-state of the next block. The (from, to) parameters are the sequence of blocks to search, which can go either forwards or backwards.
Note: to get the last state pass in the range of blocks in reverse, i.e. (last, first).
Console
debug.getAccessibleState(from, to rpc.BlockNumber)
RPC
{"method": "debug_getAccessibleState", "params": [from, to]}
debug_getBadBlocks
debug_getBadBlocks
Returns a list of the last 'bad blocks' that the client has seen on the network and returns them as a JSON list of block-hashes.
Console
debug.getBadBlocks()
RPC
{"method": "debug_getBadBlocks", "params": []}
debug_getRawBlock
debug_getRawBlock
Retrieves and returns the RLP encoded block by number.
Go
debug.getRawBlock(blockNrOrHash) (string, error)
Console
debug.getBlockRlp(blockNrOrHash)
RPC
{"method": "debug_getRawBlock", "params": [blockNrOrHash]}
References: RLP
debug_getRawHeader
debug_getRawHeader
Returns an RLP-encoded header.
Console
debug.getRawHeader(blockNrOrHash)
RPC
{"method": "debug_getRawHeader", "params": [blockNrOrHash]}
debug_getRawTransaction
debug_getRawTransaction
Returns the bytes of the transaction.
Console
debug.getRawTransaction(hash)
RPC
{"method": "debug_getRawTransaction", "params": [transactionHash]}
debug_getModifiedAccountsByHash
debug_getModifiedAccountsByHash
Returns all accounts that have changed between the two blocks specified. A change is defined as a difference in nonce, balance, code hash, or storage hash. With one parameter, returns the list of accounts modified in the specified block.
Console
debug.getModifiedAccountsByHash(startHash, endHash)
RPC
{"method": "debug_getModifiedAccountsByHash", "params": [startHash, endHash]}
debug_getModifiedAccountsByNumber
debug_getModifiedAccountsByNumber
Returns all accounts that have changed between the two blocks specified. A change is defined as a difference in nonce, balance, code hash or storage hash.
Console
debug.getModifiedAccountsByNumber(startNum uint64, endNum uint64)
RPC
{"method": "debug_getModifiedAccountsByNumber", "params": [startNum, endNum]}
Note
Geth only keeps recent trie nodes and preimages of keys in memory - for older blocks this information is deleted by Geth's garbage collection. This means that calls to debug_GetModifiedAccountsByNumber on blocks that are old enough to be eligible for garbage collection will return an error due to the trie nodes and preimages being unavailable. To fix this, run Geth with --cache.preimages=true to prevent the relevant data being lost to the garbage collector
debug_getRawReceipts
debug_getRawReceipts
Returns the consensus-encoding of all receipts in a single block.
Console
debug.getRawReceipts(blockNrOrHash)
RPC
{"method": "debug_getRawReceipts", "params": [blockNrOrHash]}
debug_goTrace
debug_goTrace
Turns on Go runtime tracing for the given duration and writes trace data to disk.
Console
debug.goTrace(file, seconds)
RPC
{"method": "debug_goTrace", "params": [string, number]}
debug_intermediateRoots
debug_intermediateRoots
Executes a block (bad- or canon- or side-), and returns a list of intermediate roots: the stateroot after each transaction.
Console
debug.intermediateRoots(blockHash, [options])
RPC
{"method": "debug_intermediateRoots", "params": [blockHash, {}]}
debug_memStats
debug_memStats
Returns detailed runtime memory statistics.
See https://golang.org/pkg/runtime/#MemStats for information about the fields of the returned object.
Console
debug.memStats()
RPC
{"method": "debug_memStats", "params": []}
debug_mutexProfile
debug_mutexProfile
Turns on mutex profiling for nsec seconds and writes profile data to file. It uses a profile rate of 1 for most accurate information. If a different rate is desired, set the rate and write the profile manually.
Console
debug.mutexProfile(file, nsec)
RPC
{"method": "debug_mutexProfile", "params": [file, nsec]}
debug_preimage
debug_preimage
Returns the preimage for a sha3 hash, if known.
Console
debug.preimage(hash)
RPC
{"method": "debug_preimage", "params": [hash]}
debug_printBlock
debug_printBlock
Retrieves a block and returns its pretty printed form.
Console
debug.printBlock(number uint64)
RPC
{"method": "debug_printBlock", "params": [number]}
debug_setBlockProfileRate
debug_setBlockProfileRate
Sets the rate (in samples/sec) of goroutine block profile data collection. A non-zero rate enables block profiling, setting it to zero stops the profile. Collected profile data can be written using debug_writeBlockProfile.
Console
debug.setBlockProfileRate(rate)
RPC
{"method": "debug_setBlockProfileRate", "params": [number]}
debug_setGCPercent
debug_setGCPercent
Sets the garbage collection target percentage. A negative value disables garbage collection.
Go
debug.SetGCPercent(v int)
Console
debug.setGCPercent(v)
RPC
{"method": "debug_setGCPercent", "params": [v]}
debug_setHead
debug_setHead
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.
Go
debug.SetHead(number uint64)
Console
debug.setHead(number)
RPC
{"method": "debug_setHead", "params": [number]}
References: Ethash
debug_setMutexProfileFraction
debug_setMutexProfileFraction
Sets the rate of mutex profiling.
Console
debug.setMutexProfileFraction(rate int)
RPC
{"method": "debug_setMutexProfileFraction", "params": [rate]}
debug_setTrieFlushInterval
debug_setTrieFlushInterval
Configures how often in-memory state tries are persisted to disk. The interval needs to be in a format parsable by a time.Duration. Note that the interval is not wall-clock time. Rather it is accumulated block processing time after which the state should be flushed. For example the value 0s will essentially turn on archive mode. If set to 1h, it means that after one hour of effective block processing time, the trie would be flushed. If one block takes 200ms, a flush would occur every 5*3600=18000 blocks. The default interval for mainnet is 1h.
Note: this configuration will not be persisted through restarts.
Console
debug.setTrieFlushInterval(interval string)
RPC
{"method": "debug_setTrieFlushInterval", "params": [interval]}
debug_stacks
debug_stacks
Returns a printed representation of the stacks of all goroutines. Note that the web3 wrapper for this method takes care of the printing and does not return the string.
Console
debug.stacks(filter *string)
RPC
{"method": "debug_stacks", "params": [filter]}
debug_standardTraceBlockToFile
debug_standardTraceBlockToFile
When JS-based tracing (see below) was first implemented, the intended usecase was to enable long-running tracers that could stream results back via a subscription channel. This method works a bit differently. (For full details, see PR)
It streams output to disk during the execution, to not blow up the memory usage on the node
It uses jsonl as output format (to allow streaming)
Uses a cross-client standardized output, so called 'standard json'
Uses op for string-representation of opcode, instead of op/opName for numeric/string, and other similar small differences.
has refund
Represents memory as a contiguous chunk of data, as opposed to a list of 32-byte segments like debug_traceTransaction
This means that this method is only 'useful' for callers who control the node -- at least sufficiently to be able to read the artefacts from the filesystem after the fact.
The method can be used to dump a certain transaction out of a given block:
Or all txs from a block:
Files are created in a temp-location, with the naming standard block_<blockhash:4>-<txindex>-<txhash:4>-<random suffix>. Each opcode immediately streams to file, with no in-geth buffering aside from whatever buffering the os normally does.
On the server side, it also adds some more info when regenerating historical state, namely, the reexec-number if required historical state is not available is encountered, so a user can experiment with increasing that setting. It also prints out the remaining block until it reaches target:
INFO [10-15|13:48:25.263] Regenerating historical state block=2385959 target=2386012 remaining=53 elapsed=3m30.990537767s INFO [10-15|13:48:33.342] Regenerating historical state block=2386012 target=2386012 remaining=0 elapsed=3m39.070073163s INFO [10-15|13:48:33.343] Historical state regenerated block=2386012 elapsed=3m39.070454362s nodes=10.03mB preimages=652.08kB INFO [10-15|13:48:33.352] Wrote trace file=/tmp/block_0x14490c57-0-0xfbbd6d91-715824834 INFO [10-15|13:48:33.352] Wrote trace file=/tmp/block_0x14490c57-1-0x71076194-187462969 INFO [10-15|13:48:34.421] Wrote trace file=/tmp/block_0x14490c57-2-0x3f4263fe-056924484
The options is as follows:
debug_standardTraceBadBlockToFile
debug_standardTraceBadBlockToFile
This method is similar to debug_standardTraceBlockToFile, but can be used to obtain info about a block which has been rejected as invalid (for some reason).
debug_startCPUProfile
debug_startCPUProfile
Turns on CPU profiling indefinitely, writing to the given file.
Console
debug.startCPUProfile(file)
RPC
{"method": "debug_startCPUProfile", "params": [string]}
debug_startGoTrace
debug_startGoTrace
Starts writing a Go runtime trace to the given file.
Console
debug.startGoTrace(file)
RPC
{"method": "debug_startGoTrace", "params": [string]}
debug_stopCPUProfile
debug_stopCPUProfile
Stops an ongoing CPU profile.
Console
debug.stopCPUProfile()
RPC
{"method": "debug_stopCPUProfile", "params": []}
debug_stopGoTrace
debug_stopGoTrace
Stops writing the Go runtime trace.
Console
debug.stopGoTrace()
RPC
{"method": "debug_stopGoTrace", "params": []}
debug_storageRangeAt
debug_storageRangeAt
Returns the storage at the given block height and transaction index. The result can be paged by providing a maxResult to cap the number of storage slots returned as well as specifying the offset via keyStart (hash of storage key).
Console
debug.storageRangeAt(blockHash, txIdx, contractAddress, keyStart, maxResult)
RPC
{"method": "debug_storageRangeAt", "params": [blockHash, txIdx, contractAddress, keyStart, maxResult]}
debug_traceBadBlock
debug_traceBadBlock
Returns the structured logs created during the execution of EVM against a block pulled from the pool of bad ones and returns them as a JSON object. For the second parameter see TraceConfig reference.
Console
debug.traceBadBlock(blockHash, [options])
RPC
{"method": "debug_traceBadBlock", "params": [blockHash, {}]}
debug_traceBlock
debug_traceBlock
The traceBlock method will return a full stack trace of all invoked opcodes of all transaction that were included in this block. Note, the parent of this block must be present or it will fail. For the second parameter see TraceConfig reference.
Go
debug.TraceBlock(blockRlp []byte, config *TraceConfig) BlockTraceResult
Console
debug.traceBlock(tblockRlp, [options])
RPC
{"method": "debug_traceBlock", "params": [blockRlp, {}]}
References: RLP
Example:
debug_traceBlockByNumber
debug_traceBlockByNumber
Similar to debug_traceBlock, traceBlockByNumber accepts a block number and will replay the block that is already present in the database. For the second parameter see TraceConfig reference.
Go
debug.TraceBlockByNumber(number uint64, config *TraceConfig) BlockTraceResult
Console
debug.traceBlockByNumber(number, [options])
RPC
{"method": "debug_traceBlockByNumber", "params": [number, {}]}
References: RLP
debug_traceBlockByHash
debug_traceBlockByHash
Similar to debug_traceBlock, traceBlockByHash accepts a block hash and will replay the block that is already present in the database. For the second parameter see TraceConfig reference.
Go
debug.TraceBlockByHash(hash common.Hash, config *TraceConfig) BlockTraceResult
Console
debug.traceBlockByHash(hash, [options])
RPC
{"method": "debug_traceBlockByHash", "params": [hash {}]}
References: RLP
debug_traceBlockFromFile
debug_traceBlockFromFile
Similar to debug_traceBlock, traceBlockFromFile accepts a file containing the RLP of the block. For the second parameter see TraceConfig reference.
Go
debug.TraceBlockFromFile(fileName string, config *TraceConfig) BlockTraceResult
Console
debug.traceBlockFromFile(fileName, [options])
RPC
{"method": "debug_traceBlockFromFile", "params": [fileName, {}]}
References: RLP
debug_traceCall
debug_traceCall
The debug_traceCall method lets you run an eth_call within the context of the given block execution using the final state of parent block as the base. The first argument (just as in eth_call) is a transaction object. The block can be specified either by hash or by number as the second argument. The trace can be configured similar to debug_traceTransaction, see TraceConfig. The method returns the same output as debug_traceTransaction.
Go
debug.TraceCall(args ethapi.CallArgs, blockNrOrHash rpc.BlockNumberOrHash, config *TraceConfig) (*ExecutionResult, error)
Console
debug.traceCall(object, blockNrOrHash, [options])
RPC
{"method": "debug_traceCall", "params": [object, blockNrOrHash, {}]}
Example:
No specific call options:
Tracing a call with a destination and specific sender, disabling the storage and memory output (less data returned over RPC)
It is possible to supply 'overrides' for both state-data (accounts/storage) and block data (number, timestamp etc). In the example below, a call which executes NUMBER is performed, and the overridden number is placed on the stack:
Curl example:
debug_traceChain
debug_traceChain
Returns the structured logs created during the execution of EVM between two blocks (excluding start) as a JSON object. This endpoint must be invoked via debug_subscribe as follows:
please refer to the subscription page for more details.
debug_traceTransaction
debug_traceTransaction
OBS In most scenarios, debug.standardTraceBlockToFile is better suited for tracing!
The traceTransaction debugging method will attempt to run the transaction in the exact same manner as it was executed on the network. It will replay any transaction that may have been executed prior to this one before it will finally attempt to execute the transaction that corresponds to the given hash.
Go
debug.TraceTransaction(txHash common.Hash, config *TraceConfig) (*ExecutionResult, error)
Console
debug.traceTransaction(txHash, [options])
RPC
{"method": "debug_traceTransaction", "params": [txHash, {}]}
TraceConfig
In addition to the hash of the transaction you may give it a secondary optional argument, which specifies the options for this specific call. The possible options are:
disableStorage: BOOL. Setting this to true will disable storage capture (default = false).
disableStack: BOOL. Setting this to true will disable stack capture (default = false).
enableMemory: BOOL. Setting this to true will enable memory capture (default = false).
enableReturnData: BOOL. Setting this to true will enable return data capture (default = false).
tracer: STRING. Name for built-in tracer or Javascript expression. See below for more details.
If set, the previous four arguments will be ignored.
timeout: STRING. Overrides the default timeout of 5 seconds for JavaScript-based tracing calls. Valid values are described here.
tracerConfig: Config for the specified tracer. For example see callTracer's config.
Geth comes with a bundle of built-in tracers, each providing various data about a transaction. This method defaults to the struct logger. The tracer field of the second parameter can be set to use any of the other tracers. Alternatively a custom tracer can be implemented in either Go or Javascript.
Example:
debug_verbosity
debug_verbosity
Sets the logging verbosity ceiling. Log messages with level up to and including the given level will be printed.
The verbosity of individual packages and source files can be raised using debug_vmodule.
Console
debug.verbosity(level)
RPC
{"method": "debug_verbosity", "params": [number]}
debug_vmodule
debug_vmodule
Sets the logging verbosity pattern.
Console
debug.vmodule(string)
RPC
{"method": "debug_vmodule", "params": [string]}
Examples:
If you want to see messages from a particular Go package (directory) and all subdirectories, use:
If you want to restrict messages to a particular package (e.g. p2p) but exclude subdirectories, use:
If you want to see log messages from a particular source file, use
You can compose these basic patterns. If you want to see all output from peer.go in a package below eth (eth/peer.go, eth/downloader/peer.go) as well as output from package p2p at level <= 5, use:
debug_writeBlockProfile
debug_writeBlockProfile
Writes a goroutine blocking profile to the given file.
Console
debug.writeBlockProfile(file)
RPC
{"method": "debug_writeBlockProfile", "params": [string]}
debug_writeMemProfile
debug_writeMemProfile
Writes an allocation profile to the given file. Note that the profiling rate cannot be set through the API, it must be set on the command line using the --pprof.memprofilerate flag.
Console
debug.writeMemProfile(file string)
RPC
{"method": "debug_writeBlockProfile", "params": [string]}
debug_writeMutexProfile
debug_writeMutexProfile
Writes a goroutine blocking profile to the given file.
Console
debug.writeMutexProfile(file)
RPC
{"method": "debug_writeMutexProfile", "params": [file]}
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