revset: optimize "draft() & ::x" pattern...
revset: optimize "draft() & ::x" pattern
The `draft() & ::x` type query could be common for selecting one or more
draft feature branches being worked on.
Before this patch, `::x` may travel through the changelog DAG for a long
distance until it gets a smaller revision number than `min(draft())`. It
could be very slow on long changelog with distant (in terms of revision
numbers) drafts.
This patch adds a fast path for this situation, and will stop traveling the
changelog DAG once `::x` hits a non-draft revision.
The fast path also works for `secret()` and `not public()`.
To measure the performance difference, I used drawdag to create a repo that
emulates distant drafts:
DRAFT4
|
DRAFT3 # draft
/
PUBLIC9999 # public
|
PUBLIC9998
|
. DRAFT2
. |
. DRAFT1 # draft
| /
PUBLIC0001 # public
And measured the performance using the repo:
(BEFORE)
$ hg perfrevset 'draft() & ::(DRAFT2+DRAFT4)'
! wall 0.017132 comb 0.010000 user 0.010000 sys 0.000000 (best of 156)
$ hg perfrevset 'draft() & ::(all())'
! wall 0.024221 comb 0.030000 user 0.030000 sys 0.000000 (best of 113)
(AFTER)
$ hg perfrevset 'draft() & ::(DRAFT2+DRAFT4)'
! wall 0.000243 comb 0.000000 user 0.000000 sys 0.000000 (best of 9303)
$ hg perfrevset 'draft() & ::(all())'
! wall 0.004319 comb 0.000000 user 0.000000 sys 0.000000 (best of 655)
Differential Revision:
https://phab.mercurial-scm.org/D441
