view tests/test-sqlitestore.t @ 44386:8f7c6656ac79

rust-nodemap: pure Rust example

To run, use `cargo run --release --example nodemap`

This demonstrates that simple scenarios entirely written
in Rust can content themselves with `NodeTree<T>`.

The example mmaps both the nodemap file and the changelog index.
We had of course to include an implementation of `RevlogIndex`
directly, which isn't much at this stage. It felt a bit
prematurate to include it in the lib.

Here are some first performance measurements, obtained with
this example, on a clone of mozilla-central with 440000
changesets:

  (create) Nodemap constructed in RAM in 153.638305ms
  (query CAE63161B68962) found in 22.362us: Ok(Some(269489))
  (bench) Did 3 queries in 36.418µs (mean 12.139µs)
  (bench) Did 50 queries in 184.318µs (mean 3.686µs)
  (bench) Did 100000 queries in 31.053461ms (mean 310ns)

To be fair, even between bench runs, results tend to depend whether
the file is still in kernel caches, and it's not so easy to
get back to a real cold start. The worst we've seen was in the
50us ballpark.

In any busy server setting, the pages would always be in RAM.

We hope it's good enough not to be significantly slower on any
concrete Mercurial operation than the C nodetree when fully in RAM,
and of course this implementation has the serious headstart advantage
of persistence.

Differential Revision: https://phab.mercurial-scm.org/D7797

#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 ..