Make initial block index loading faster #1420
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WalkthroughThe update introduces a flexible mechanism for checking the Proof of Work (PoW) of blockchain blocks during client startup. It adds an option to either perform a comprehensive PoW check for all blocks or limit the verification to the most recent ones, depending on a specified flag. This enhancement aims to improve startup efficiency without compromising the integrity of the blockchain. Changes
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| //! By default don't check block index PoW on client startup | ||
| static const bool DEFAULT_FULL_BLOCKINDEX_CHECK = false; | ||
| //! If not doing full check of block index, check only N of the latest blocks | ||
| static const int DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK = 10000; |
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The introduction of DEFAULT_FULL_BLOCKINDEX_CHECK and DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK constants is a significant change aimed at optimizing the initial block index loading process. However, there are a few considerations and recommendations:
- Documentation: It's crucial to document these constants, explaining their purpose, usage, and the rationale behind the default values. This will aid in maintainability and understanding for future developers.
- Configuration Flexibility: While the PR introduces a mechanism to control the depth of the block index check via a flag, consider exposing
DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECKas a configurable parameter (e.g., via a configuration file or command-line argument). This would provide operators with greater flexibility in tuning the system based on their specific needs or constraints. - Validation: Ensure that there is validation in place for the
DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECKvalue, especially if it becomes user-configurable. For example, negative values should be disallowed, and there might be a reasonable upper limit to consider.
+ // Documentation for DEFAULT_FULL_BLOCKINDEX_CHECK
+ // Documentation for DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK
+ // Consider making DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK configurable
+ // Add validation for DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECKCommittable suggestion
‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation.
| //! By default don't check block index PoW on client startup | |
| static const bool DEFAULT_FULL_BLOCKINDEX_CHECK = false; | |
| //! If not doing full check of block index, check only N of the latest blocks | |
| static const int DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK = 10000; | |
| //! By default don't check block index PoW on client startup | |
| // Documentation for DEFAULT_FULL_BLOCKINDEX_CHECK | |
| static const bool DEFAULT_FULL_BLOCKINDEX_CHECK = false; | |
| //! If not doing full check of block index, check only N of the latest blocks | |
| // Documentation for DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK | |
| // Consider making DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK configurable | |
| // Add validation for DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK | |
| static const int DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK = 10000; |
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| pindexNew->activeDisablingSporks = diskindex.activeDisablingSporks; | ||
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| if (!CheckProofOfWork(pindexNew->GetBlockPoWHash(), pindexNew->nBits, consensusParams)) | ||
| return error("LoadBlockIndex(): CheckProofOfWork failed: %s", pindexNew->ToString()); | ||
| if (fCheckPoWForAllBlocks) { | ||
| if (!CheckProofOfWork(pindexNew->GetBlockPoWHash(), pindexNew->nBits, consensusParams)) | ||
| return error("LoadBlockIndex(): CheckProofOfWork failed: %s", pindexNew->ToString()); | ||
| } | ||
| else { | ||
| if (pindexNew->nHeight >= firstInLastNBlocksHeight) { | ||
| lastNBlocks.insert(std::pair<int, CBlockIndex*>(pindexNew->nHeight, pindexNew)); | ||
| if (lastNBlocks.size() > DEFAULT_BLOCKINDEX_NUMBER_OF_BLOCKS_TO_CHECK) { | ||
| // pop the first element from the map | ||
| auto firstElement = lastNBlocks.begin(); | ||
| auto elementToPop = firstElement++; | ||
| lastNBlocks.erase(elementToPop); | ||
| firstInLastNBlocksHeight = firstElement->first; | ||
| } | ||
| } | ||
| } | ||
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| pcursor->Next(); | ||
| } else { |
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📝 NOTE
This review was outside the diff hunks and was mapped to the diff hunk with the greatest overlap. Original lines [359-452]
The modifications to CBlockTreeDB::LoadBlockIndexGuts introduce a conditional check for Proof of Work (PoW) based on the -fullblockindexcheck flag and the number of most recent blocks. While this optimization aims to improve the initial block index loading speed, there are several areas that require attention:
- Correctness: The logic for selectively checking PoW for the most recent blocks appears sound. However, ensure thorough testing, especially around edge cases such as blockchain reorganizations that might affect the set of the most recent blocks.
- Performance: This change could significantly impact startup times. It would be beneficial to quantify this impact through benchmarking under various scenarios (e.g., with and without the flag enabled, with different values for the number of blocks to check).
- Maintainability: The added complexity to
LoadBlockIndexGutsincreases the cognitive load for future maintainers. Consider refactoring to improve readability and maintainability. For example, extracting the logic for managinglastNBlocksinto separate functions could make the code more modular and easier to understand. - Error Handling: Ensure that any failures in PoW checks lead to clear and actionable error messages, aiding in troubleshooting potential issues during startup.
+ // Refactor to improve maintainability
+ // Benchmark to quantify performance impact
+ // Ensure thorough testing, especially around edge cases
+ // Improve error handling and messaging
PR intention
Speed up loading block index from disk.
Code changes brief
Code eliminates the check of PoW for all the block headers except last 10000.
Summary by CodeRabbit