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Diffstat (limited to 'Documentation/technical/reftable.md')
| -rw-r--r-- | Documentation/technical/reftable.md | 26 |
1 files changed, 15 insertions, 11 deletions
diff --git a/Documentation/technical/reftable.md b/Documentation/technical/reftable.md index 5140e624ef..9e5c521fca 100644 --- a/Documentation/technical/reftable.md +++ b/Documentation/technical/reftable.md @@ -775,12 +775,12 @@ directory. This prevents loose references from being stored. A collection of reftable files are stored in the `$GIT_DIR/reftable/` directory: - 00000001.log - 00000001.ref - 00000002.ref + 00000001-00000001.log + 00000002-00000002.ref + 00000003-00000003.ref where reftable files are named by a unique name such as produced by -the function `${update_index}.ref`. +the function `${min_update_index}-${max_update_index}.ref`. Log-only files use the `.log` extension, while ref-only and mixed ref and log files use `.ref`. extension. @@ -790,9 +790,9 @@ files, one per line, in order, from oldest (base) to newest (most recent): $ cat .git/refs - 00000001.log - 00000001.ref - 00000002.ref + 00000001-00000001.log + 00000002-00000002.ref + 00000003-00000003.ref Readers must read `$GIT_DIR/refs` to determine which files are relevant right now, and search through the stack in reverse order @@ -819,8 +819,8 @@ new reftable and atomically appending it to the stack: 1. Acquire `refs.lock`. 2. Read `refs` to determine current reftables. 3. Select `update_index` to be most recent file's `max_update_index + 1`. -4. Prepare temp reftable `${update_index}_XXXXXX`, including log entries. -5. Rename `${update_index}_XXXXXX` to `${update_index}.ref`. +4. Prepare temp reftable `tmp_XXXXXX`, including log entries. +5. Rename `tmp_XXXXXX` to `${update_index}-${update_index}.ref`. 6. Copy `refs` to `refs.lock`, appending file from (5). 7. Rename `refs.lock` to `refs`. @@ -865,12 +865,13 @@ is going to compact B and C, leaving A and D alone. Ownership of these locks prevents other processes from trying to compact these files. 3. Release `refs.lock`. -4. Compact `B` and `C` into a temp file `${min_update_index}_XXXXXX`. +4. Compact `B` and `C` into a temp file `${min_update_index}-${max_update_index}_XXXXXX`. 5. Reacquire lock `refs.lock`. 6. Verify that `B` and `C` are still in the stack, in that order. This should always be the case, assuming that other processes are adhering to the locking protocol. -7. Rename `${min_update_index}_XXXXXX` to `${min_update_index}_2.ref`. +7. Rename `${min_update_index}-${max_update_index}_XXXXXX` to + `${min_update_index}-${max_update_index}.ref`. 8. Write the new stack to `refs.lock`, replacing `B` and `C` with the file from (4). 9. Rename `refs.lock` to `refs`. @@ -879,6 +880,9 @@ is going to compact B and C, leaving A and D alone. This strategy permits compactions to proceed independently of updates. +Each reftable (compacted or not) is uniquely identified by its name, so open +reftables can be cached by their name. + ## Alternatives considered ### bzip packed-refs |