execution/commitment: let trie warmup borrow branch bytes instead of copying them - #23585
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execution/commitment: let trie warmup borrow branch bytes instead of copying them#23585AskAlexSharov wants to merge 4 commits into
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TrieContext.Branch copies every branch it reads, because the trie's own consumers retain the bytes past the read: Merge, the encoder and merger buffers, and the deferred-update queues. Warmup retains nothing -- it pulls the child bitmap, a byte of field bits per cell and an extension length, all scalars, to pick the next nibble -- yet it pays the same copy, and it issues several times more branch reads than the fold does. WarmupBranch hands back the read uncopied. The bytes stay valid for the life of the context's transaction: mdbx guarantees that for a read, mmapped .kv pages are pinned by it, and the mem batch and the branch/state caches all store heap-owned values. Callers that keep branch data stay on Branch. Selected once per warmup worker rather than per key, so the interface assertion and the method value stay off the per-key path.
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The name now says what it does. The doc says what the caller owes: the result aliases the reader's memory and must not be retained or mutated. Branch copies because the trie's consumers do both, not because the source is short-lived.
…xt-call The tighter promise leaves the reader free to hand back a reused buffer later. The fake now poisons what the previous call returned, so a caller that keeps the bytes across a read descends differently and the test fails.
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| // not be mutated. Branch copies because the trie's consumers keep branch data | ||
| // past that. | ||
| type BranchNoCopyReader interface { | ||
| BranchNoCopy(prefix []byte) ([]byte, kv.Step, error) |
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why not add this to the PatriciaContext interface?
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warmuper does read/copy/despose branch value. let's try to avoid