Questions tagged [leveldb]
LevelDB is an embedded key-value storage developed by Google that is used in Bitcoin Core for block index storage and quick access to the UTXO set (unspent transaction outputs).
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Unable to parse blocks from blk*.dat for testnet (3 and 4)
For the Bitcoin mainnet, I can easily fetch one block by following steps:
Open the LevelDB database at <bitcoind-dir>/data/blocks/index
Get by key: ...
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levelDB : How does the key/values pairs work for datadir/blocks/index/
I'm trying to understand the format of key/value pairs in LevelDB for Bitcoin data storage.
Given the following raw key and value:
Raw Key: ...
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Repeated corruption issue with bitcoind
I'm trying to index the entire chain for spent P2PK inputs for this program I'm writing, and whenever I get to this transaction - 7a8394fd438d9fbe6b36ce38e5b0ca65037f864d1007236775ac3532b886ebe1 - I ...
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How to decode bitcoin node's chainstate data stored in LevelDB?
I am trying to decode the data available in the chainstate. After doing some research, I see that Google's LevelDB is mentioned (like in this post). However, I am still not sure how to effectively and ...
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I can't parse the UTXO from the chainstate
I have a problem with reading tx out from the Bitcoin Core LevelDB chainstate storage. I know that the structure of the current version of the chainstate is key => value where the key is a prefix (...
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Transaction incorrect when reading a block from `blk*.dat` files
The problem occurs with block 1,669,774 on testnet (https://blockstream.info/testnet/block/0000000010001cebd3e4f2fe5f2e2cbbe35ba6457554d9e0e6eb100b6f91eaee).
To obtain a block I retrieve the file and ...
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Does Bitcoin Core write blockchain and chainstate data atomically?
In particular, when a new block arrives:
Is the block written to disk in an atomic fashion, so a new block either exists, or it doesn't? (reader can never see a partially written state)
Are the ...
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When does chainstate get updated?
What i'm trying to do now is reading LevelDB at chainstate folder to save all utxos at my own DB, and keep tracking the changes of utxos by looking at chainstate folder frequently.
However, what i ...
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LevelDB error after power outage
After a power outage, starting bitcoind I recieved this errors (circled in the image). Reading online some users suggest to do a reindex and i did it but after 11 hours my node isn't reindex yet... ...
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Number of transactions per blk.dat files
I am working on a parser for the blk.dat files being returned by the Bitcoin Core node. It seems to slow down considerably after a point and I am pretty sure it's because the number of transactions is ...
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Regarding the chainstate level db (UXTO)
Already found many useful information regarding the chainstats db.
such as:
What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?
But what is the meanning of the last ...
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Getting wrong version number of block from block index of Bitcoin Core
I am reading block index using plyvel python package.
Following is the location of block indexes:
export BLOCK_INDEX_DB=$BITCOIN_HOME/blocks/index
Following is the method to decode b128 varint:
def ...
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Are the block headers kept in memory?
Bitcoin Core keeps block data as files in the file system and blocks indexes in a LevelDB database to make the search process of transactions and blocks faster. But Bitcoin Core also stores block ...
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Cannot unserialize chainstate transaction outputs after de-obfuscation
I was able to read chainstate database.
Getting the key and de-obfuscating to get a valid last block.
However, when it comes to transactions that follow after that,
I cannot de-serialize them no ...
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Bitcoin - Level DB - Block Index - Parsing value for block hash
I am trying to read the value against block hash in level DB of Bitcoin node database - Block/index. For Genesis block, I get 88 bytes which I want to parse. I tried to follow instructions in https://...
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Bitcoin - Read transaction details from LevelDB
I am new to LevelDB and the way BTC keeps everything in the database. I went through article How does Bitcoin read from/write to LevelDB but was not able to get to the first step -
Transaction
...
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What is the relationship between LevelDB's cache (default 8MB) and Bitcoin's UTXO cache?
Please correct me if I am wrong.
Bitcoin uses levelDB to store UTXO set. LevelDB has a default 8MB block cache, and the Bitcoin also has a dbcache(default 450MB).
What is the relationship between the ...
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When the UTXO in the cache is full, what strategy is used to replace one UTXO with another in the cache?
The UTXO set is stored on the disk, but some UTXOs are also stored in the cache. When validating a transaction, you need to query the UTXO pointed to by the input of the transaction. First, you go to ...
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How does bitcoin find the block locator hashes in the leveldb database?
I am trying to understand how bitcoin core builds the list of block locator hashes needed for sendheaders and getheaders messages. I have looked on the wiki and I have seen that after the 10 most ...
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What is in the Bitcoin Core LevelDB dbcache? Is it full records or metadata?
What is in the Bitcoin Core LevelDB dbcache? Is it full records or metadata?
This question was asked on IRC by Anonymous.
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Error opening block database Full node
For some reason my node shutdown and now I get when restart it
Error opening block database
here my bitcoin.conf
txindex=1
reindex=1
reindex-chainstate=1
# Accept command line and JSON-RPC ...
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What can cause the chainstate database to become corrupted?
I have written a tool that accesses the chainstate LevelDB database to get a list of UTXOs.
https://github.com/in3rsha/bitcoin-utxo-dump/blob/master/utxodump.go
The tool would originally corrupt the ...
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why is bitcoind daemon occasionally stuck at `Opening LevelDB in .../.bitcoin/chainstate`despite clean shutdown
My bitcoind daemon sometimes takes an hour to go past Opening LevelDB in .../.bitcoin/chainstate
After googling a bit, i thought it was simply an unclean daemon stop causing a leveldb corruption. But ...
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How Does Bitcoin Core Client Keep Track of Longest Chain/Strongest PoW Chains?
Bitcoin Core stores blocks in files in local disk. And it uses LevelDb to form an index on top of block storage to make it faster to retrieve a block (basically a simple key-value pair db). See this ...
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Bitcoind Node crashes after using -dbcache option
I've been trying to speed up my node sync by increasing the dbcache. However my node tends to crash overnight. My system is running ubuntu 18.04, 4GM of ram bitcoin core v0.18.
I've tried bitcoind -...
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CDiskBlockIndex: NFile and NDataPos not defined
This is the source code snippet that is used for the serialization of block indexes (found in leveldb).
Block 478573 index is (as of my node's leveldb) ...
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How to get the block hash in the chainstate leveldb?
From this link What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?,
to get the block hash I use the obfuscation key and xor it with the result I get from the db. So I ...
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How exactly do I decode the block file info in leveldb?
Base on the links
https://github.com/bitcoin/bitcoin/blob/fcbc8bfa6d10cac4f16699d6e6e68fb6eb98acd0/src/main.h#L392 and
What are the keys used in the blockchain levelDB (ie what are the key:value ...
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How to parse values in block index leveldb?
So I'm trying to read the block files with Python.
From this link,
What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?, it tells you how to access the files with ...
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Does the chainstate leveldb only contain "addresses" for P2PKH and P2SH?
I'm writing a small script that will dump the utxo database to a text file. As far as I'm aware, these are the most common script patterns indicated by the type field inside each value:
e.g. value: ...
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How does Bitcoin use its communication protocol and its database model?
In terms of Bitcoin's communication protocol, how does Bitcoin allow nodes to communicate between each other?
Is Bitcoin's communication protocol the same as IPFS(InterPlanetary File System) and if ...
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Python - Querying bitcoin's block header using leveldb
I am facing a stupid problem. I am trying to read bitcoin/blocks/index leveldb using plyvel. I've set up a regtest and i know there is a block with the hash :
...
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EXCEPTION: 15dbwrapper_error
I'm running Bitcoind 0.17 on a raspberry Pi 3. Everything ran smoothly until I did something wrong (I guess) but can't figure out what happened. Now I got this error. Has someone experience with this ...
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why is bitcoin leveldb separated in so many small pieces?
Currently I could see 1418 ldb files on my box, from 210040.ldb to 215423.ldb (some missing).
Why are they separated in this way?
I want to read the leveldb using golang, but I don't know which one ...
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How can I get the key of blockindex
According to this post: What are the keys used in the blockchain levelDB (ie what are the key:value pairs)?
One type of the keys in leveldb of bitcoin is formed in the following way
'b' + 32-byte ...
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Get value from leveldb bitcoin using node.js?
I request information about the block 100001 using leveldb and node js.
Below is my code example.
var level = require('level');
var db = level('E:/download/blockchain/block');
var str = '...
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Why was Bitcoin Core in need of a fork of LevelDB?
Why did Bitcoin Core fork LevelDB? What special needs does Bitcoin Core have, which require a specialized version of LevelDB?
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Why is wallet.dat BerkeleyDB instead of LevelDB?
Why wasn't wallet.dat migrated to LevelDB?
Is it because
BerkeleyDB is better at [something]
Backwards compatibility
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bitcoin chainstate database parsing in python giving wrong value
I am trying to decode chainstate db for a specific out index for a transaction in python just for learning.
Transaction ID: 4d4a4c6ca4f3c91e69563199943336d3279fad71c9e8d9c1708ef9dc6ac16000
out index = ...
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Very hard to sync Core Client from scratch
Recently I started running a Core 15.1 node with the blockchain on an external hard drive, and found it very hard to fully sync the blockchain.
The problem I keep running into is that (in about 90% of ...
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Trojans detected in ldb bitcoin database?
I started regular scan and clamscan found lots of trojans in bitcon.lfb blocks.
What is it? A mistake?
sudo clamscan --infected --recursive --exclude-dir="^/sys" /
/root/.bitcoin/data/blocks/index/...
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Bitcoin blockchain in mongodb
How bad would it be to use MongoDB as a Bitcoin database instead of LevelDB? I know that LevelDB is faster but I've also read that MongoDB is better for doing queries.
It seems cleaner to store the ...
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Format of a block key's contents in bitcoind's LevelDB?
I am trying to use bitcoind's LevelDB block index files (that are stored in blocks/index) to find the file (e.g. blk00029.dat) and byte position of specfic blocks.
Thanks to questions What is the ...
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How to delete last n blocks / roll back to specific block number in Bitcoin Core? (Like `monero-blockchain-import --pop-blocks n`)
I have Bitcoin Core's bitcoind running and synced in a VM. Now I want to clone the VM and run one of the various hard forks (such as Bitcoin Cash) in the clone. The plan is to roll back my copy of the ...
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How does bitcoind store blocks?
I want to parse blockchain manually and extract the UTXO set (for various reasons). Is there any way to understand how the blocks are stored without going through the C++ code?
Some specs will be ...
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Non-obfuscated chainstate data
I'm wondering if there is a flag that allows running bitcoind without using an obfuscation key for the chainstate. I haven't been able to find it.
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Chainstate Bitcoin Core 0.15
Recently updated my LevelDB parser to work with the new LevelDB 0.15 internal structure. However, I'm wondering about two small changes I found:
The prefix for transactions was changed from b'c' to b'...
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how to build altcoin in mingw?
OS : Windows 10
Installed Dependencies:
-qt4.8.6
gcc 6.3.0
boost 1_55_0
berkeleyDB 4.8.30NC
openssl 1.0.2l
I tried compiling with the following commands:
qmake "USE_UPNP=1" coin-pt.pro
mingw32-...
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What will happen when the blockchain size will reach 1 Tb? Or 10 Tb?
My question is more about bitcoin client (bitcoind). Will it still be working fine or maybe something will go wrong? I mean, maybe LevelDB can't handle this amount of data correctly?
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Bcoin - Database backend not found
/root/BCoin/node_modules/bcoin/lib/db/backends.js:16
throw new Error('Database backend "' + name + '" not found.');
^
Error: Database backend "leveldown" not found.
at Object.get (/root/...
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