view tests/test-sqlitestore.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 sqlite

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > sqlitestore =
  > EOF

New repo should not use SQLite by default

  $ hg init empty-no-sqlite
  $ cat empty-no-sqlite/.hg/requires
  dotencode
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store

storage.new-repo-backend=sqlite is recognized

  $ hg --config storage.new-repo-backend=sqlite init empty-sqlite
  $ cat empty-sqlite/.hg/requires
  dotencode
  exp-sqlite-001
  exp-sqlite-comp-001=zstd (zstd !)
  exp-sqlite-comp-001=$BUNDLE2_COMPRESSIONS$ (no-zstd !)
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store

  $ cat >> $HGRCPATH << EOF
  > [storage]
  > new-repo-backend = sqlite
  > EOF

Can force compression to zlib

  $ hg --config storage.sqlite.compression=zlib init empty-zlib
  $ cat empty-zlib/.hg/requires
  dotencode
  exp-sqlite-001
  exp-sqlite-comp-001=$BUNDLE2_COMPRESSIONS$
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store

Can force compression to none

  $ hg --config storage.sqlite.compression=none init empty-none
  $ cat empty-none/.hg/requires
  dotencode
  exp-sqlite-001
  exp-sqlite-comp-001=none
  fncache
  generaldelta
  revlogv1
  sparserevlog
  store

Can make a local commit

  $ hg init local-commit
  $ cd local-commit
  $ echo 0 > foo
  $ hg commit -A -m initial
  adding foo

That results in a row being inserted into various tables

  $ sqlite3 .hg/store/db.sqlite -init /dev/null << EOF
  > SELECT * FROM filepath;
  > EOF
  1|foo

  $ sqlite3 .hg/store/db.sqlite -init /dev/null << EOF
  > SELECT * FROM fileindex;
  > EOF
  1|1|0|-1|-1|0|0|1||6/\xef(L\xe2\xca\x02\xae\xcc\x8d\xe6\xd5\xe8\xa1\xc3\xaf\x05V\xfe (esc)

  $ sqlite3 .hg/store/db.sqlite -init /dev/null << EOF
  > SELECT * FROM delta;
  > EOF
  1|1|	\xd2\xaf\x8d\xd2"\x01\xdd\x8dH\xe5\xdc\xfc\xae\xd2\x81\xff\x94"\xc7|0 (esc)
  

Tracking multiple files works

  $ echo 1 > bar
  $ hg commit -A -m 'add bar'
  adding bar

  $ sqlite3 .hg/store/db.sqlite -init /dev/null << EOF
  > SELECT * FROM filedata ORDER BY id ASC;
  > EOF
  1|1|foo|0|6/\xef(L\xe2\xca\x02\xae\xcc\x8d\xe6\xd5\xe8\xa1\xc3\xaf\x05V\xfe|-1|-1|0|0|1| (esc)
  2|2|bar|0|\xb8\xe0/d3s\x80!\xa0e\xf9Au\xc7\xcd#\xdb_\x05\xbe|-1|-1|1|0|2| (esc)

Multiple revisions of a file works

  $ echo a >> foo
  $ hg commit -m 'modify foo'

  $ sqlite3 .hg/store/db.sqlite -init /dev/null << EOF
  > SELECT * FROM filedata ORDER BY id ASC;
  > EOF
  1|1|foo|0|6/\xef(L\xe2\xca\x02\xae\xcc\x8d\xe6\xd5\xe8\xa1\xc3\xaf\x05V\xfe|-1|-1|0|0|1| (esc)
  2|2|bar|0|\xb8\xe0/d3s\x80!\xa0e\xf9Au\xc7\xcd#\xdb_\x05\xbe|-1|-1|1|0|2| (esc)
  3|1|foo|1|\xdd\xb3V\xcd\xde1p@\xf7\x8e\x90\xb8*\x8b,\xe9\x0e\xd6j+|0|-1|2|0|3|1 (esc)

  $ cd ..