This tightens up the decision making by adding two requirements:
1. The peer must return the same number of summaries to the ones requested.
2. The peer must return a summary that matches its latest reported signature.
This ensures we are always making sync decisions based on accurate data, and removes peers that are currently mid re-org. This is probably more validation than is actually necessary, but it's best to be really thorough here so it is as optimized as possible.
We have gone backwards and forwards on this one a lot recently, but now that stability has returned, it is best to tighten this up. Previously it was loosened to help reduce network load, but that is no longer a problem. With this stricter approach, it should prevent a node ending up in an incomplete state after syncing, which is the main cause of the shorter re-orgs we are seeing.
The existing HSQL export/import (PERFORM EXPORT SCRIPT and PERFORM IMPORT SCRIPT) have been replaced with a custom JSON import and export. Whilst this is less generic, it has some significant advantages:
- When exporting data, it is now able to combine the exported data with any data that already exists in the backup file. This prevents a backup after a bootstrap from overwriting data from before the bootstrap, and removes the need for all of the "archive" files that we currently create.
- Adds support for partial imports, and updates. Previously an import would fail if any of the data being imported already existed in the db. It will now add new rows and update existing ones.
- The format and contents of the exported trade bot data now matches the output of the /crosschain/tradebot API.
- Data is retrieved without the need for a database lock, and therefore the export process is much faster and less invasive. This should prevent the lockups and other problems seen when using the trade portal.
For now, there are a couple of trade-offs to using this new approach:
- The minting key import/export has been temporarily removed until there is more time to transition it to this new format.
- Existing .script backups can no longer be imported using versions higher than 1.5.1.
Both of these can be solved by temporarily running version 1.5.1, performing the necessary imports/exports, then returning to the latest version. Longer term the minting keys export/import will be reimplemented using the JSON format.
This controls whether to allow connections with peers below minPeerVersion.
If true, we won't sync with them but they can still sync with us, and will show in the peers list. This is the default, which allows older nodes to continue functioning, but prevents them from interfering with the sync behaviour of updated nodes.
If false, sync will be blocked both ways, and they will not appear in the peers list at all.
The script will fetch a set of blocks and then backtest the specified blockTimings settings (target, deviation, and power) against those real life blocks. This allows configurations to be fine tuned to tighten up block times, and to adjust the timestamp variance between levels.
Usage:
block-timings.sh <startheight> <count> [target] [deviation] [power]
startheight: a block height, preferably within the untrimmed range, to avoid data gaps
count: the number of blocks to request and analyse after the start height. Default: 100
target: the target block time in milliseconds. Originates from blockchain.json. Default: 60000
deviation: the allowed block time deviation in milliseconds. Originates from blockchain.json. Default: 30000
power: used when transforming key distance to a time offset. Originates from blockchain.json. Default: 0.2
Initially set to 10 when used by the /crosschain/price/{blockchain} API, so that the price is based on the last 10 trades rather than every trade that has ever taken place.
Block.calcKeyDistance() cannot be called on some trimmed blocks, because the minter level is unable to be inferred in some cases. This generally hasn't been an issue, but the new Block.logDebugInfo() method is invoking it for all blocks. For now I am adding defensiveness to the debug method, but longer term we might want to add defensiveness to Block.calcKeyDistance() itself, if we ever encounter this issue again. I will leave it alone for now, to reduce risk.
This includes updating AdoptOpenJDK to version 11.0.11.9, because 11.0.6.10 is no longer recommended or available in their archive. It also looks like I am using a newer version of AdvancedInstaller itself.
Again, this wouldn't have affected anything in 1.5.0 or before, but it will become more significant if we switch to same-length chain weight comparisons.
This gives an insight into the contents of each chain when doing a re-org. To enable this logging, add the following to log4j2.properties:
logger.block.name = org.qortal.block.Block
logger.block.level = debug
This solves a common problem that is mostly seen when starting a node that has been switched off for some time, or when starting from a bootstrap. In these cases, it can be difficult get synced to the latest if you are starting from a small fork. This is because it required that the node was brought up to date via a single peer, and there wasn't much room for error if it failed to retrieve a block a couple of times. This generally caused the blocks to be thrown away and it would try the same process over and over.
The solution is to apply new blocks if the most recently received block is newer than our current latest block. This gets the node back on to the main fork where it can then sync using the regular applyNewBlocks() method.
