Re: [PATCH 0/3] Use commit-graph by default

[Derrick Stolee]

On 10/17/2018 11:47 PM, Junio C Hamano wrote:

If I recall correctly, one more task that was discussed but hasn't
been addressed well is how the generation and incremental update of
it should integrate with the normal repository maintenance workflow
(perhaps "gc --auto").  If we are going to turn it on by default, it
would be good to see if we can avoid multiple independent walks done
over the same history graph by repack, prune and now commit-graph,
before such a change happens.
I don't remember a discussion on this, but it is an interesting point. 
I'll give it some thought to see if we can combine these walks.


Thanks,
-Stolee

Re: [PATCH 0/3] Use commit-graph by default

[Junio C Hamano]

"Derrick Stolee via GitGitGadget"  writes:

> The commit-graph feature is starting to stabilize. Based on what is in
> master right now, we have:
>
> Git 2.18:
>
>  * Ability to write commit-graph (requires user interaction).
>
>
>  * Commit parsing is faster when commit-graph exists.
>
>
>  * Must have core.commitGraph true to use.
>
>
>
> Git 2.19:
>
>  * Ability to write commit-graph on GC with gc.writeCommitGraph.
>
>
>  * Generation numbers written in commit-graph
>
>
>  * A few reachability algorithms make use of generation numbers.
>
>
>
> (queued for) master:
>
>  * The test suite passes with GIT_TEST_COMMIT_GRAPH=1
>
>
>  * 'git commit-graph write' has progress indicators.
>
>
>  * The commit-graph is automatically disabled when grafts or replace-objects
>exist.

If I recall correctly, one more task that was discussed but hasn't
been addressed well is how the generation and incremental update of
it should integrate with the normal repository maintenance workflow
(perhaps "gc --auto").  If we are going to turn it on by default, it
would be good to see if we can avoid multiple independent walks done
over the same history graph by repack, prune and now commit-graph,
before such a change happens.

Thanks.

[PATCH 0/3] Use commit-graph by default

[Derrick Stolee via GitGitGadget]

The commit-graph feature is starting to stabilize. Based on what is in
master right now, we have:

Git 2.18:

 * Ability to write commit-graph (requires user interaction).
   
   
 * Commit parsing is faster when commit-graph exists.
   
   
 * Must have core.commitGraph true to use.
   
   

Git 2.19:

 * Ability to write commit-graph on GC with gc.writeCommitGraph.
   
   
 * Generation numbers written in commit-graph
   
   
 * A few reachability algorithms make use of generation numbers.
   
   

(queued for) master:

 * The test suite passes with GIT_TEST_COMMIT_GRAPH=1
   
   
 * 'git commit-graph write' has progress indicators.
   
   
 * The commit-graph is automatically disabled when grafts or replace-objects
   exist.
   
   

There are some other things coming that are in review (like 'git log
--graph' speedups), but it is probably time to consider enabling the
commit-graph by default. This series does that.

For timing, I'm happy to leave this queued for a merge after the Git 2.20
release. There are enough things in master to justify not enabling this by
default until that goes out and more people use it.

PATCH 3/3 is rather simple, and is the obvious thing to do to achieve
enabling these config values by default.

PATCH 1/3 is a required change to make the test suite work with this change.
This change isn't needed with GIT_TEST_COMMIT_GRAPH=1 because the
commit-graph is up-to-date for these 'git gc' calls, so no progress is
output.

PATCH 2/3 is also a necessary evil, since we already had to disable
GIT_TEST_COMMIT_GRAPH for some tests, we now also need to turn off
core.commitGraph.

Thanks, -Stolee

Derrick Stolee (3):
  t6501: use --quiet when testing gc stderr
  t: explicitly turn off core.commitGraph as needed
  commit-graph: Use commit-graph by default

 Documentation/config.txt| 4 ++--
 builtin/gc.c| 2 +-
 commit-graph.c  | 6 +++---
 t/t0410-partial-clone.sh| 3 ++-
 t/t5307-pack-missing-commit.sh  | 3 ++-
 t/t6011-rev-list-with-bad-commit.sh | 3 ++-
 t/t6024-recursive-merge.sh  | 3 ++-
 t/t6501-freshen-objects.sh  | 6 +++---
 8 files changed, 17 insertions(+), 13 deletions(-)


base-commit: a4b8ab5363a32f283a61ef3a962853556d136c0e
Published-As: 
https://github.com/gitgitgadget/git/releases/tags/pr-50%2Fderrickstolee%2Fcommit-graph-default-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git 
pr-50/derrickstolee/commit-graph-default-v1
Pull-Request: https://github.com/gitgitgadget/git/pull/50
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