view tests/test-obsolete-changeset-exchange.t @ 30212:260af19891f2

changegroup: increase write buffer size to 128k

By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.

This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.

It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.

When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).

This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.

Test changesets filtering during exchanges (some tests are still in
test-obsolete.t)

  $ cat >> $HGRCPATH << EOF
  > [experimental]
  > evolution=createmarkers
  > EOF

Push does not corrupt remote
----------------------------

Create a DAG where a changeset reuses a revision from a file first used in an
extinct changeset.

  $ hg init local
  $ cd local
  $ echo 'base' > base
  $ hg commit -Am base
  adding base
  $ echo 'A' > A
  $ hg commit -Am A
  adding A
  $ hg up 0
  0 files updated, 0 files merged, 1 files removed, 0 files unresolved
  $ hg revert -ar 1
  adding A
  $ hg commit -Am "A'"
  created new head
  $ hg log -G --template='{desc} {node}'
  @  A' f89bcc95eba5174b1ccc3e33a82e84c96e8338ee
  |
  | o  A 9d73aac1b2ed7d53835eaeec212ed41ea47da53a
  |/
  o  base d20a80d4def38df63a4b330b7fb688f3d4cae1e3
  
  $ hg debugobsolete 9d73aac1b2ed7d53835eaeec212ed41ea47da53a f89bcc95eba5174b1ccc3e33a82e84c96e8338ee

Push it. The bundle should not refer to the extinct changeset.

  $ hg init ../other
  $ hg push ../other
  pushing to ../other
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 2 changesets with 2 changes to 2 files
  $ hg -R ../other verify
  checking changesets
  checking manifests
  crosschecking files in changesets and manifests
  checking files
  2 files, 2 changesets, 2 total revisions

Adding a changeset going extinct locally
------------------------------------------

Pull a changeset that will immediatly goes extinct (because you already have a
marker to obsolete him)
(test resolution of issue3788)

  $ hg phase --draft --force f89bcc95eba5
  $ hg phase -R ../other --draft --force f89bcc95eba5
  $ hg commit --amend -m "A''"
  $ hg --hidden --config extensions.mq= strip  --no-backup f89bcc95eba5
  $ hg pull ../other
  pulling from ../other
  searching for changes
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 1 files (+1 heads)
  (run 'hg heads' to see heads, 'hg merge' to merge)

check that bundle is not affected

  $ hg bundle --hidden --rev f89bcc95eba5 --base "f89bcc95eba5^" ../f89bcc95eba5.hg
  1 changesets found
  $ hg --hidden --config extensions.mq= strip --no-backup f89bcc95eba5
  $ hg unbundle ../f89bcc95eba5.hg
  adding changesets
  adding manifests
  adding file changes
  added 1 changesets with 0 changes to 1 files (+1 heads)
  (run 'hg heads' to see heads)
  $ cd ..

pull does not fetch excessive changesets when common node is hidden (issue4982)
-------------------------------------------------------------------------------

initial repo with server and client matching

  $ hg init pull-hidden-common
  $ cd pull-hidden-common
  $ touch foo
  $ hg -q commit -A -m initial
  $ echo 1 > foo
  $ hg commit -m 1
  $ echo 2a > foo
  $ hg commit -m 2a
  $ cd ..
  $ hg clone --pull pull-hidden-common pull-hidden-common-client
  requesting all changes
  adding changesets
  adding manifests
  adding file changes
  added 3 changesets with 3 changes to 1 files
  updating to branch default
  1 files updated, 0 files merged, 0 files removed, 0 files unresolved

server obsoletes the old head

  $ cd pull-hidden-common
  $ hg -q up -r 1
  $ echo 2b > foo
  $ hg -q commit -m 2b
  $ hg debugobsolete 6a29ed9c68defff1a139e5c6fa9696fb1a75783d bec0734cd68e84477ba7fc1d13e6cff53ab70129
  $ cd ..

client only pulls down 1 changeset

  $ cd pull-hidden-common-client
  $ hg pull --debug
  pulling from $TESTTMP/pull-hidden-common (glob)
  query 1; heads
  searching for changes
  taking quick initial sample
  query 2; still undecided: 2, sample size is: 2
  2 total queries
  1 changesets found
  list of changesets:
  bec0734cd68e84477ba7fc1d13e6cff53ab70129
  listing keys for "phases"
  listing keys for "bookmarks"
  bundle2-output-bundle: "HG20", 3 parts total
  bundle2-output-part: "changegroup" (params: 1 mandatory 1 advisory) streamed payload
  bundle2-output-part: "listkeys" (params: 1 mandatory) 58 bytes payload
  bundle2-output-part: "listkeys" (params: 1 mandatory) empty payload
  bundle2-input-bundle: with-transaction
  bundle2-input-part: "changegroup" (params: 1 mandatory 1 advisory) supported
  adding changesets
  add changeset bec0734cd68e
  adding manifests
  adding file changes
  adding foo revisions
  added 1 changesets with 1 changes to 1 files (+1 heads)
  updating the branch cache
  bundle2-input-part: total payload size 476
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-part: total payload size 58
  bundle2-input-part: "listkeys" (params: 1 mandatory) supported
  bundle2-input-bundle: 2 parts total
  checking for updated bookmarks
  (run 'hg heads' to see heads, 'hg merge' to merge)