repository: Avoid duplicate index lookup when loading blob/tree#2629
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MichaelEischer wants to merge 1 commit intorestic:masterfrom
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repository: Avoid duplicate index lookup when loading blob/tree#2629MichaelEischer wants to merge 1 commit intorestic:masterfrom
MichaelEischer wants to merge 1 commit intorestic:masterfrom
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loadBlob() must lookup the blob in the index anyways. loadBlob can now allocate a blob buffer. This removes the need for size lookups in LoadTree.
greatroar
reviewed
Mar 8, 2020
| // large enough to hold the complete blob. | ||
| func (r *Repository) loadBlob(ctx context.Context, id restic.ID, t restic.BlobType, plaintextBuf []byte) (int, error) { | ||
| debug.Log("load %v with id %v (buf len %v, cap %d)", t, id, len(plaintextBuf), cap(plaintextBuf)) | ||
| func (r *Repository) loadBlob(ctx context.Context, id restic.ID, t restic.BlobType, plaintextBuf []byte) ([]byte, int, error) { |
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The second return value is redundant. The []byte can be sliced to the right length before return.
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What is the purpose of this change? What does it change?
LoadBlobandLoadTreelookup the blob size in the index and use it to allocate a buffer forloadBlobwhich has to run another index lookup. Especially for large repositories index lookups are rather expensive, see #2523 .This PR lets
loadBlob()allocate the blob buffer itself and thus removes the duplicate index lookup.I did not include a changelog entry as this PR only slightly improves performance.
Was the change discussed in an issue or in the forum before?
No, the inefficiency showed up during work on #2328.
Checklist
[ ] I have added documentation for the changes (in the manual)[ ] There's a new file inchangelog/unreleased/that describes the changes for our users (template here)gofmton the code in all commits