view tests/test-remotefilelog-http.t @ 42743:8c9a6adec67a

rust-discovery: using the children cache in add_missing

The DAG range computation often needs to get back to very old
revisions, and turns out to be disproportionately long, given
that the end goal is to remove the descendents of the given
missing revisons from the undecided set.

The fast iteration capabilities available in the Rust case make
it possible to avoid the DAG range entirely, at the cost of
precomputing the children cache, and to simply iterate on
children of the given missing revisions.

This is a case where staying on the same side of the interface
between the two languages has clear benefits.

On discoveries with initial undecided sets
small enough to bypass sampling entirely, the total cost of
computing the children cache and the subsequent iteration
becomes better than the Python + C counterpart, which relies on
reachableroots2.

For example, on a repo with more than one million revisions with
an initial undecided set of 11 elements, we get these figures:

Rust version with simple iteration
  addcommons: 57.287us
  first undecided computation: 184.278334ms
  first children cache computation: 131.056us
  addmissings iteration: 42.766us
  first addinfo total: 185.24 ms

Python + C version
  first addcommons: 0.29 ms
  addcommons 0.21 ms
  first undecided computation 191.35 ms
  addmissings 45.75 ms
  first addinfo total: 237.77 ms

On discoveries with large undecided sets, the initial price paid
makes the first addinfo slower than the Python + C version,
but that's more than compensated by the gain in sampling and
subsequent iterations.
Here's an extreme example with an undecided set of a million revisions:

Rust version:
  first undecided computation: 293.842629ms
  first children cache computation: 407.911297ms
  addmissings iteration: 34.312869ms
  first addinfo total: 776.02 ms
  taking initial sample
  query 2: sampling time: 1318.38 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings: 143.062us

Python + C version:
  first undecided computation 298.13 ms
  addmissings 80.13 ms
  first addinfo total: 399.62 ms
  taking initial sample
  query 2: sampling time: 3957.23 ms
  query 2; still undecided: 1005013, sample size is: 200
  addmissings 52.88 ms

Differential Revision: https://phab.mercurial-scm.org/D6428

#require no-windows

  $ . "$TESTDIR/remotefilelog-library.sh"

  $ hg init master
  $ cd master
  $ cat >> .hg/hgrc <<EOF
  > [remotefilelog]
  > server=True
  > EOF
  $ echo x > x
  $ echo y > y
  $ hg commit -qAm x
  $ hg serve -p $HGPORT -d --pid-file=../hg1.pid -E ../error.log -A ../access.log

Build a query string for later use:
  $ GET=`hg debugdata -m 0 | $PYTHON -c \
  > 'import sys ; print([("?cmd=x_rfl_getfile&file=%s&node=%s" % tuple(s.split("\0"))) for s in sys.stdin.read().splitlines()][0])'`

  $ cd ..
  $ cat hg1.pid >> $DAEMON_PIDS

  $ hgcloneshallow http://localhost:$HGPORT/ shallow -q
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

  $ grep getfile access.log
  * "GET /?cmd=batch HTTP/1.1" 200 - x-hgarg-1:cmds=x_rfl_getfile+*node%3D1406e74118627694268417491f018a4a883152f0* (glob)

Clear filenode cache so we can test fetching with a modified batch size
  $ rm -r $TESTTMP/hgcache
Now do a fetch with a large batch size so we're sure it works
  $ hgcloneshallow http://localhost:$HGPORT/ shallow-large-batch \
  >    --config remotefilelog.batchsize=1000 -q
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

The 'remotefilelog' capability should *not* be exported over http(s),
as the getfile method it offers doesn't work with http.
  $ get-with-headers.py localhost:$HGPORT '?cmd=capabilities' | grep lookup | identifyrflcaps
  x_rfl_getfile
  x_rfl_getflogheads

  $ get-with-headers.py localhost:$HGPORT '?cmd=hello' | grep lookup | identifyrflcaps
  x_rfl_getfile
  x_rfl_getflogheads

  $ get-with-headers.py localhost:$HGPORT '?cmd=this-command-does-not-exist' | head -n 1
  400 no such method: this-command-does-not-exist
  $ get-with-headers.py localhost:$HGPORT '?cmd=x_rfl_getfiles' | head -n 1
  400 no such method: x_rfl_getfiles

Verify serving from a shallow clone doesn't allow for remotefile
fetches. This also serves to test the error handling for our batchable
getfile RPC.

  $ cd shallow
  $ hg serve -p $HGPORT1 -d --pid-file=../hg2.pid -E ../error2.log
  $ cd ..
  $ cat hg2.pid >> $DAEMON_PIDS

This GET should work, because this server is serving master, which is
a full clone.

  $ get-with-headers.py localhost:$HGPORT "$GET"
  200 Script output follows
  
  0\x00x\x9c3b\xa8\xe0\x12a{\xee(\x91T6E\xadE\xdcS\x9e\xb1\xcb\xab\xc30\xe8\x03\x03\x91 \xe4\xc6\xfb\x99J,\x17\x0c\x9f-\xcb\xfcR7c\xf3c\x97r\xbb\x10\x06\x00\x96m\x121 (no-eol) (esc)

This GET should fail using the in-band signalling mechanism, because
it's not a full clone. Note that it's also plausible for servers to
refuse to serve file contents for other reasons, like the file
contents not being visible to the current user.

  $ get-with-headers.py localhost:$HGPORT1 "$GET"
  200 Script output follows
  
  1\x00cannot fetch remote files from shallow repo (no-eol) (esc)

Clones should work with httppostargs turned on

  $ cd master
  $ hg --config experimental.httppostargs=1 serve -p $HGPORT2 -d --pid-file=../hg3.pid -E ../error3.log

  $ cd ..
  $ cat hg3.pid >> $DAEMON_PIDS

Clear filenode cache so we can test fetching with a modified batch size
  $ rm -r $TESTTMP/hgcache

  $ hgcloneshallow http://localhost:$HGPORT2/ shallow-postargs -q
  2 files fetched over 1 fetches - (2 misses, 0.00% hit ratio) over *s (glob)

All error logs should be empty:
  $ cat error.log
  $ cat error2.log
  $ cat error3.log