[pull] master from ethereum:master #3
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
![pull[bot]](https://avatars.githubusercontent.com/in/12910?s=60&v=4){kind=small}
|
The latest updates on your projects. Learn more about Vercel for Git ↗︎
|
This PR removes the dependencies on `lightchaindata` db as the light protocol has been deprecated and removed from the codebase.
params: begin v1.14.12 release cycle
This pull request removes the `fsync` of index files in freezer.ModifyAncients function for performance gain. Originally, fsync is added after each freezer write operation to ensure the written data is truly transferred into disk. Unfortunately, it turns out `fsync` can be relatively slow, especially on macOS (see #28754 for more information). In this pull request, fsync for index file is removed as it turns out index file can be recovered even after a unclean shutdown. But fsync for data file is still kept, as we have no meaningful way to validate the data correctness after unclean shutdown. --- **But why do we need the `fsync` in the first place?** As it's necessary for freezer to survive/recover after the machine crash (e.g. power failure). In linux, whenever the file write is performed, the file metadata update and data update are not necessarily performed at the same time. Typically, the metadata will be flushed/journalled ahead of the file data. Therefore, we make the pessimistic assumption that the file is first extended with invalid "garbage" data (normally zero bytes) and that afterwards the correct data replaces the garbage. We have observed that the index file of the freezer often contain garbage entry with zero value (filenumber = 0, offset = 0) after a machine power failure. It proves that the index file is extended without the data being flushed. And this corruption can destroy the whole freezer data eventually. Performing fsync after each write operation can reduce the time window for data to be transferred to the disk and ensure the correctness of the data in the disk to the greatest extent. --- **How can we maintain this guarantee without relying on fsync?** Because the items in the index file are strictly in order, we can leverage this characteristic to detect the corruption and truncate them when freezer is opened. Specifically these validation rules are performed for each index file: For two consecutive index items: - If their file numbers are the same, then the offset of the latter one MUST not be less than that of the former. - If the file number of the latter one is equal to that of the former plus one, then the offset of the latter one MUST not be 0. - If their file numbers are not equal, and the latter's file number is not equal to the former plus 1, the latter one is valid And also, for the first non-head item, it must refer to the earliest data file, or the next file if the earliest file is not sufficient to place the first item(very special case, only theoretical possible in tests) With these validation rules, we can detect the invalid item in index file with greatest possibility. --- But unfortunately, these scenarios are not covered and could still lead to a freezer corruption if it occurs: **All items in index file are in zero value** It's impossible to distinguish if they are truly zero (e.g. all the data entries maintained in freezer are zero size) or just the garbage left by OS. In this case, these index items will be kept by truncating the entire data file, namely the freezer is corrupted. However, we can consider that the probability of this situation occurring is quite low, and even if it occurs, the freezer can be considered to be close to an empty state. Rerun the state sync should be acceptable. **Index file is integral while relative data file is corrupted** It might be possible the data file is corrupted whose file size is extended correctly with garbage filled (e.g. zero bytes). In this case, it's impossible to detect the corruption by index validation. We can either choose to `fsync` the data file, or blindly believe that if index file is integral then the data file could be integral with very high chance. In this pull request, the first option is taken.
Remove console extensions for already deleted API namespaces (les, vflux and ethash).
The bulk of this PR is authored by @lightclient , in the original EOF-work. More recently, the code has been picked up and reworked for the new EOF specification, by @MariusVanDerWijden , in #29518, and also @shemnon has contributed with fixes. This PR is an attempt to start eating the elephant one small bite at a time, by selecting only the eof-validation as a standalone piece which can be merged without interfering too much in the core stuff. In this PR: - [x] Validation of eof containers, lifted from #29518, along with test-vectors from consensus-tests and fuzzing, to ensure that the move did not lose any functionality. - [x] Definition of eof opcodes, which is a prerequisite for validation - [x] Addition of `undefined` to a jumptable entry item. I'm not super-happy with this, but for the moment it seems the least invasive way to do it. A better way might be to go back and allowing nil-items or nil execute-functions to denote "undefined". - [x] benchmarks of eof validation speed --------- Co-authored-by: lightclient <[email protected]> Co-authored-by: Marius van der Wijden <[email protected]> Co-authored-by: Danno Ferrin <[email protected]>
minimizes the time when the lock is held
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
See Commits and Changes for more details.
Created by
pull[bot]
Can you help keep this open source service alive? 💖 Please sponsor : )