changegroup: compute seen files as changesets are added (
issue4750)
Before this patch, addchangegroup() would walk the changelog and compute
the set of seen files between applying changesets and applying
manifests. When cloning large repositories such as mozilla-central,
this consumed a non-trivial amount of time. On my MBP, this walk takes
~10s. On a dainty EC2 instance, this was measured to take ~125s! On the
latter machine, this delay was enough for the Mercurial server to
disconnect the client, thinking it had timed out, thus causing a clone
to abort.
This patch enables the changelog to compute the set of changed files as
new revisions are added. By doing so, we:
* avoid a potentially heavy computation between changelog and manifest
processing by spreading the computation across all changelog additions
* avoid extra reads from the changelog by operating on the data as it is
added
The downside of this is that the add revision callback does result in
extra I/O. Before, we would perform a flush (and subsequent read to
construct the full revision) when new delta chains were created. For
changelogs, this is typically every 2-4 revisions. Using the callback
guarantees there will be a flush after every added revision *and* an
open + read of the changelog to obtain the full revision in order to
read the added files. So, this increases the frequency of these
operations by the average chain length. In the future, the revlog
should be smart enough to know how to read revisions that haven't been
flushed yet, thus eliminating this extra I/O.
On my MBP, the total CPU times for an `hg unbundle` with a local
mozilla-central gzip bundle containing 251,934 changesets and 211,065
files did not have a statistically significant change with this patch,
holding steady around 360s. So, the increased revlog flushing did not
have an effect.
With this patch, there is no longer a visible pause between applying
changeset and manifest data. Before, it sure felt like Mercurial was
lethargic making this transition. Now, the transition is nearly
instantaneous, giving the impression that Mercurial is faster. Of course,
eliminating this pause means that the potential for network disconnect due
to channel inactivity during the changelog walk is eliminated as well.
And that is the impetus behind this change.
$ echo "[extensions]" >> $HGRCPATH
$ echo "mq=" >> $HGRCPATH
$ echo "[diff]" >> $HGRCPATH
$ echo "nodates=true" >> $HGRCPATH
$ catlog() {
> cat .hg/patches/$1.patch | sed -e "s/^diff \-r [0-9a-f]* /diff -r ... /" \
> -e "s/^\(# Parent \).*/\1/"
> hg log --template "{rev}: {desc} - {author}\n"
> }
$ runtest() {
> echo ==== init
> hg init a
> cd a
> hg qinit
>
>
> echo ==== qnew -U
> hg qnew -U 1.patch
> catlog 1
>
> echo ==== qref
> echo "1" >1
> hg add
> hg qref
> catlog 1
>
> echo ==== qref -u
> hg qref -u mary
> catlog 1
>
> echo ==== qnew
> hg qnew 2.patch
> echo "2" >2
> hg add
> hg qref
> catlog 2
>
> echo ==== qref -u
> hg qref -u jane
> catlog 2
>
>
> echo ==== qnew -U -m
> hg qnew -U -m "Three" 3.patch
> catlog 3
>
> echo ==== qref
> echo "3" >3
> hg add
> hg qref
> catlog 3
>
> echo ==== qref -m
> hg qref -m "Drei"
> catlog 3
>
> echo ==== qref -u
> hg qref -u mary
> catlog 3
>
> echo ==== qref -u -m
> hg qref -u maria -m "Three (again)"
> catlog 3
>
> echo ==== qnew -m
> hg qnew -m "Four" 4.patch
> echo "4" >4of t
> hg add
> hg qref
> catlog 4
>
> echo ==== qref -u
> hg qref -u jane
> catlog 4
>
>
> echo ==== qnew with HG header
> hg qnew --config 'mq.plain=true' 5.patch
> hg qpop
> echo "# HG changeset patch" >>.hg/patches/5.patch
> echo "# User johndoe" >>.hg/patches/5.patch
> hg qpush 2>&1 | grep 'now at'
> catlog 5
>
> echo ==== hg qref
> echo "5" >5
> hg add
> hg qref
> catlog 5
>
> echo ==== hg qref -U
> hg qref -U
> catlog 5
>
> echo ==== hg qref -u
> hg qref -u johndeere
> catlog 5
>
>
> echo ==== qnew with plain header
> hg qnew --config 'mq.plain=true' -U 6.patch
> hg qpop
> hg qpush 2>&1 | grep 'now at'
> catlog 6
>
> echo ==== hg qref
> echo "6" >6
> hg add
> hg qref
> catlog 6
>
> echo ==== hg qref -U
> hg qref -U
> catlog 6
>
> echo ==== hg qref -u
> hg qref -u johndeere
> catlog 6
>
>
> echo ==== "qpop -a / qpush -a"
> hg qpop -a
> hg qpush -a
> hg log --template "{rev}: {desc} - {author}\n"
> }
======= plain headers
$ echo "[mq]" >> $HGRCPATH
$ echo "plain=true" >> $HGRCPATH
$ mkdir sandbox
$ (cd sandbox ; runtest)
==== init
==== qnew -U
From: test
0: [mq]: 1.patch - test
==== qref
adding 1
From: test
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - test
==== qref -u
From: mary
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - mary
==== qnew
adding 2
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - test
0: [mq]: 1.patch - mary
==== qref -u
From: jane
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -U -m
From: test
Three
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref
adding 3
From: test
Three
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -m
From: test
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
From: mary
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - mary
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u -m
From: maria
Three (again)
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -m
adding 4of
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - test
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
From: jane
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with HG header
popping 5.patch
now at: 4.patch
now at: 5.patch
# HG changeset patch
# User johndoe
4: imported patch 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 5
# HG changeset patch
# User johndoe
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
# HG changeset patch
# User test
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - test
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
# HG changeset patch
# User johndeere
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with plain header
popping 6.patch
now at: 5.patch
now at: 6.patch
From: test
5: imported patch 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 6
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
From: johndeere
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - johndeere
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qpop -a / qpush -a
popping 6.patch
popping 5.patch
popping 4.patch
popping 3.patch
popping 2.patch
popping 1.patch
patch queue now empty
applying 1.patch
applying 2.patch
applying 3.patch
applying 4.patch
applying 5.patch
applying 6.patch
now at: 6.patch
5: imported patch 6.patch - johndeere
4: imported patch 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: imported patch 2.patch - jane
0: imported patch 1.patch - mary
$ rm -r sandbox
======= hg headers
$ echo "plain=false" >> $HGRCPATH
$ mkdir sandbox
$ (cd sandbox ; runtest)
==== init
==== qnew -U
# HG changeset patch
# User test
# Parent
0: [mq]: 1.patch - test
==== qref
adding 1
# HG changeset patch
# User test
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - test
==== qref -u
# HG changeset patch
# User mary
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - mary
==== qnew
adding 2
# HG changeset patch
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - test
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -U -m
# HG changeset patch
# User test
# Parent
Three
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref
adding 3
# HG changeset patch
# User test
# Parent
Three
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -m
# HG changeset patch
# User test
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User mary
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - mary
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u -m
# HG changeset patch
# User maria
# Parent
Three (again)
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -m
adding 4of
# HG changeset patch
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - test
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with HG header
popping 5.patch
now at: 4.patch
now at: 5.patch
# HG changeset patch
# User johndoe
4: imported patch 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 5
# HG changeset patch
# User johndoe
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
# HG changeset patch
# User test
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - test
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
# HG changeset patch
# User johndeere
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with plain header
popping 6.patch
now at: 5.patch
now at: 6.patch
From: test
5: imported patch 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 6
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
From: johndeere
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - johndeere
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qpop -a / qpush -a
popping 6.patch
popping 5.patch
popping 4.patch
popping 3.patch
popping 2.patch
popping 1.patch
patch queue now empty
applying 1.patch
applying 2.patch
applying 3.patch
applying 4.patch
applying 5.patch
applying 6.patch
now at: 6.patch
5: imported patch 6.patch - johndeere
4: imported patch 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: imported patch 2.patch - jane
0: imported patch 1.patch - mary
$ rm -r sandbox
$ runtest
==== init
==== qnew -U
# HG changeset patch
# User test
# Parent
0: [mq]: 1.patch - test
==== qref
adding 1
# HG changeset patch
# User test
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - test
==== qref -u
# HG changeset patch
# User mary
# Parent
diff -r ... 1
--- /dev/null
+++ b/1
@@ -0,0 +1,1 @@
+1
0: [mq]: 1.patch - mary
==== qnew
adding 2
# HG changeset patch
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - test
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
diff -r ... 2
--- /dev/null
+++ b/2
@@ -0,0 +1,1 @@
+2
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -U -m
# HG changeset patch
# User test
# Parent
Three
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref
adding 3
# HG changeset patch
# User test
# Parent
Three
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -m
# HG changeset patch
# User test
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - test
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User mary
# Parent
Drei
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Drei - mary
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u -m
# HG changeset patch
# User maria
# Parent
Three (again)
diff -r ... 3
--- /dev/null
+++ b/3
@@ -0,0 +1,1 @@
+3
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew -m
adding 4of
# HG changeset patch
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - test
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qref -u
# HG changeset patch
# User jane
# Parent
Four
diff -r ... 4of
--- /dev/null
+++ b/4of
@@ -0,0 +1,1 @@
+4 t
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with HG header
popping 5.patch
now at: 4.patch
now at: 5.patch
# HG changeset patch
# User johndoe
4: imported patch 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 5
# HG changeset patch
# User johndoe
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndoe
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
# HG changeset patch
# User test
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - test
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
# HG changeset patch
# User johndeere
# Parent
diff -r ... 5
--- /dev/null
+++ b/5
@@ -0,0 +1,1 @@
+5
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qnew with plain header
popping 6.patch
now at: 5.patch
now at: 6.patch
From: test
5: imported patch 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref
adding 6
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -U
From: test
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - test
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== hg qref -u
From: johndeere
diff -r ... 6
--- /dev/null
+++ b/6
@@ -0,0 +1,1 @@
+6
5: [mq]: 6.patch - johndeere
4: [mq]: 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: [mq]: 2.patch - jane
0: [mq]: 1.patch - mary
==== qpop -a / qpush -a
popping 6.patch
popping 5.patch
popping 4.patch
popping 3.patch
popping 2.patch
popping 1.patch
patch queue now empty
applying 1.patch
applying 2.patch
applying 3.patch
applying 4.patch
applying 5.patch
applying 6.patch
now at: 6.patch
5: imported patch 6.patch - johndeere
4: imported patch 5.patch - johndeere
3: Four - jane
2: Three (again) - maria
1: imported patch 2.patch - jane
0: imported patch 1.patch - mary
$ cd ..