refactor(page_cache): introduce a sub-cache for merkle pages below a fixed depth #800
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
This stack of pull requests is managed by Graphite. Learn more about stacking. |
This was referenced Feb 11, 2025
pepyakin
approved these changes
Feb 12, 2025
|
|
||
| // Total number of nodes stored in one Page. It depends on the `DEPTH` | ||
| // of the rootless sub-binary tree stored in a page following this formula: | ||
| // (2^(DEPTH + 1)) - 2 | ||
| pub const NODES_PER_PAGE: usize = (1 << DEPTH + 1) - 2; | ||
|
|
||
| // The fixed number of levels we always preserve in-memory. | ||
| const FIXED_LEVELS: usize = 3; |
There was a problem hiding this comment.
This is slightly wrong.
If the root is the 0th level, we still keep 1st, 2nd and the 3rd levels. So the number that figures in the constant is 3 but we keep 4 levels.
| @@ -146,11 +149,50 @@ struct CacheShard { | |||
| } | |||
|
|
|||
| struct CacheShardLocked { | |||
| // storage for pages in the levels of the tree which we always cache. | |||
| fixed_level_cache: HashMap<PageId, CacheEntry, FxBuildHasher>, | |||
There was a problem hiding this comment.
Nit: "Fixed" is ok, but I wonder if something like pinned would be slightly better?
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Outdated suggestions cannot be applied.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.
This puts all pages with level <= 3 into a "fixed level cache" hash-map.
Cache eviction will never remove these pages and they can only be removed if the page itself is deleted.
This will be followed up by a PR for prepopulation.