| Message ID | 20250217-pks-update-ref-optimization-v1-3-a2b6d87a24af@pks.im (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | refs: batch refname availability checks | expand |
Patrick Steinhardt <ps@pks.im> writes: [snip] > diff --git a/builtin/update-ref.c b/builtin/update-ref.c > index 4d35bdc4b4b..ac330748244 100644 > --- a/builtin/update-ref.c > +++ b/builtin/update-ref.c > @@ -179,7 +179,8 @@ static int parse_next_oid(const char **next, const char *end, > (*next)++; > *next = parse_arg(*next, &arg); > if (arg.len) { > - if (repo_get_oid(the_repository, arg.buf, oid)) > + if (repo_get_oid_with_flags(the_repository, arg.buf, oid, > + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) > goto invalid; > } else { > /* Without -z, an empty value means all zeros: */ > @@ -197,7 +198,8 @@ static int parse_next_oid(const char **next, const char *end, > *next += arg.len; > > if (arg.len) { > - if (repo_get_oid(the_repository, arg.buf, oid)) > + if (repo_get_oid_with_flags(the_repository, arg.buf, oid, > + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) > goto invalid; > } else if (flags & PARSE_SHA1_ALLOW_EMPTY) { > /* With -z, treat an empty value as all zeros: */ So the above two instances are used within the individual sub-commands for `--stdin` mode. The symref commands use `parse_refname()` for parsing refnames, so all good. > @@ -772,7 +774,8 @@ int cmd_update_ref(int argc, > refname = argv[0]; > value = argv[1]; > oldval = argv[2]; > - if (repo_get_oid(the_repository, value, &oid)) > + if (repo_get_oid_with_flags(the_repository, value, &oid, > + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) > die("%s: not a valid SHA1", value); > } > > @@ -783,7 +786,8 @@ int cmd_update_ref(int argc, > * must not already exist: > */ > oidclr(&oldoid, the_repository->hash_algo); > - else if (repo_get_oid(the_repository, oldval, &oldoid)) > + else if (repo_get_oid_with_flags(the_repository, oldval, &oldoid, > + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) > die("%s: not a valid old SHA1", oldval); > } > This is when the user uses 'git update-ref' directly. Makes sense. > > -- > 2.48.1.666.gff9fcf71b7.dirty
diff --git a/builtin/update-ref.c b/builtin/update-ref.c index 4d35bdc4b4b..ac330748244 100644 --- a/builtin/update-ref.c +++ b/builtin/update-ref.c @@ -179,7 +179,8 @@ static int parse_next_oid(const char **next, const char *end, (*next)++; *next = parse_arg(*next, &arg); if (arg.len) { - if (repo_get_oid(the_repository, arg.buf, oid)) + if (repo_get_oid_with_flags(the_repository, arg.buf, oid, + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) goto invalid; } else { /* Without -z, an empty value means all zeros: */ @@ -197,7 +198,8 @@ static int parse_next_oid(const char **next, const char *end, *next += arg.len; if (arg.len) { - if (repo_get_oid(the_repository, arg.buf, oid)) + if (repo_get_oid_with_flags(the_repository, arg.buf, oid, + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) goto invalid; } else if (flags & PARSE_SHA1_ALLOW_EMPTY) { /* With -z, treat an empty value as all zeros: */ @@ -772,7 +774,8 @@ int cmd_update_ref(int argc, refname = argv[0]; value = argv[1]; oldval = argv[2]; - if (repo_get_oid(the_repository, value, &oid)) + if (repo_get_oid_with_flags(the_repository, value, &oid, + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) die("%s: not a valid SHA1", value); } @@ -783,7 +786,8 @@ int cmd_update_ref(int argc, * must not already exist: */ oidclr(&oldoid, the_repository->hash_algo); - else if (repo_get_oid(the_repository, oldval, &oldoid)) + else if (repo_get_oid_with_flags(the_repository, oldval, &oldoid, + GET_OID_HASH_SKIP_AMBIGUITY_CHECK)) die("%s: not a valid old SHA1", oldval); }
Most of the commands in git-update-ref(1) accept an old and/or new object ID to update a specific reference to. These object IDs get parsed via `repo_get_oid()`, which not only handles plain object IDs, but also those that have a suffix like "~" or "^2". More surprisingly though, it even knows to resolve references, despite the fact that its manpage does not mention this fact even once. One consequence of this is that we also check for ambiguous references: when parsing a full object ID where the DWIM mechanism would also cause us to resolve it as a branch, we'd end up printing a warning. While this check makes sense to have in general, it is arguably less useful in the context of git-update-ref(1). This is out of two reasons: - The manpage is explicitly structured around object IDs. So if we see a fully blown object ID, the intent should be quite clear in general. - The command is part of our plumbing layer and not a tool that users would generally use in interactive workflows. As such, the warning will likely not be visible to anybody in the first place. Furthermore, this check can be quite expensive when updating lots of references via `--stdin`, because we try to read multiple references per object ID that we parse according to the DWIM rules. This effect can be seen both with the "files" and "reftable" backend. Disable the warning in git-update-ref(1), which provides a significant speedup with both backends. The following benchmark creates 10000 new references with a 100000 preexisting refs with the "files" backend: Benchmark 1: update-ref: create many refs (refformat = files, preexisting = 100000, new = 10000, revision = HEAD~) Time (mean ± σ): 467.3 ms ± 5.1 ms [User: 100.0 ms, System: 365.1 ms] Range (min … max): 461.9 ms … 479.3 ms 10 runs Benchmark 2: update-ref: create many refs (refformat = files, preexisting = 100000, new = 10000, revision = HEAD) Time (mean ± σ): 394.1 ms ± 5.8 ms [User: 63.3 ms, System: 327.6 ms] Range (min … max): 384.9 ms … 405.7 ms 10 runs Summary update-ref: create many refs (refformat = files, preexisting = 100000, new = 10000, revision = HEAD) ran 1.19 ± 0.02 times faster than update-ref: create many refs (refformat = files, preexisting = 100000, new = 10000, revision = HEAD~) And with the "reftable" backend: Benchmark 1: update-ref: create many refs (refformat = reftable, preexisting = 100000, new = 10000, revision = HEAD~) Time (mean ± σ): 146.9 ms ± 2.2 ms [User: 90.4 ms, System: 56.0 ms] Range (min … max): 142.7 ms … 150.8 ms 19 runs Benchmark 2: update-ref: create many refs (refformat = reftable, preexisting = 100000, new = 10000, revision = HEAD) Time (mean ± σ): 63.2 ms ± 1.1 ms [User: 41.0 ms, System: 21.8 ms] Range (min … max): 61.1 ms … 66.6 ms 41 runs Summary update-ref: create many refs (refformat = reftable, preexisting = 100000, new = 10000, revision = HEAD) ran 2.32 ± 0.05 times faster than update-ref: create many refs (refformat = reftable, preexisting = 100000, new = 10000, revision = HEAD~) Note that the absolute improvement with both backends is roughly in the same ballpark, but the relative improvement for the "reftable" backend is more significant because writing the new table to disk is faster in the first place. Signed-off-by: Patrick Steinhardt <ps@pks.im> --- builtin/update-ref.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)