view tests/test-persistent-nodemap.t @ 44367:50ad851efd9b

nodemap: introduce append-only incremental update of the persistent data

Rewriting the full nodemap for each transaction has a cost we would like to
avoid. We introduce a new way to write persistent nodemap data by adding new
information at the end for file. Any new and updated block as added at the end
of the file. The last block is the new root node.

With this method, some of the block already on disk get "dereferenced" and
become dead data. In later changesets, We'll start tracking the amount of dead
data to eventually re-generate a full nodemap.

Differential Revision: https://phab.mercurial-scm.org/D7886

===================================
Test the persistent on-disk nodemap
===================================


  $ hg init test-repo
  $ cd test-repo
  $ cat << EOF >> .hg/hgrc
  > [experimental]
  > exp-persistent-nodemap=yes
  > [devel]
  > persistent-nodemap=yes
  > EOF
  $ hg debugbuilddag .+5000
  $ f --size .hg/store/00changelog.n
  .hg/store/00changelog.n: size=18
  $ f --sha256 .hg/store/00changelog-*.nd
  .hg/store/00changelog-????????????????.nd: sha256=b961925120e1c9bc345c199b2cc442abc477029fdece37ef9d99cbe59c0558b7 (glob)
  $ hg debugnodemap --dump-new | f --sha256 --size
  size=122880, sha256=b961925120e1c9bc345c199b2cc442abc477029fdece37ef9d99cbe59c0558b7
  $ hg debugnodemap --dump-disk | f --sha256 --bytes=256 --hexdump --size
  size=122880, sha256=b961925120e1c9bc345c199b2cc442abc477029fdece37ef9d99cbe59c0558b7
  0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0010: ff ff ff ff ff ff ff ff ff ff fa c2 ff ff ff ff |................|
  0020: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0030: ff ff ff ff ff ff ed b3 ff ff ff ff ff ff ff ff |................|
  0040: ff ff ff ff ff ff ee 34 00 00 00 00 ff ff ff ff |.......4........|
  0050: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0060: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0070: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  0080: ff ff ff ff ff ff f8 50 ff ff ff ff ff ff ff ff |.......P........|
  0090: ff ff ff ff ff ff ff ff ff ff ec c7 ff ff ff ff |................|
  00a0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  00b0: ff ff ff ff ff ff fa be ff ff f2 fc ff ff ff ff |................|
  00c0: ff ff ff ff ff ff ef ea ff ff ff ff ff ff f9 17 |................|
  00d0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  00e0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  00f0: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff |................|
  $ hg debugnodemap --check
  revision in index:   5001
  revision in nodemap: 5001

add a new commit

  $ hg up
  0 files updated, 0 files merged, 0 files removed, 0 files unresolved
  $ echo foo > foo
  $ hg add foo
  $ hg ci -m 'foo'
  $ f --size .hg/store/00changelog.n
  .hg/store/00changelog.n: size=18

(The pure code use the debug code that perform incremental update, the C code reencode from scratch)

#if pure
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=123072, sha256=136472751566c8198ff09e306a7d2f9bd18bd32298d614752b73da4d6df23340 (glob)

#else
  $ f --sha256 .hg/store/00changelog-*.nd --size
  .hg/store/00changelog-????????????????.nd: size=122880, sha256=bfafebd751c4f6d116a76a37a1dee2a251747affe7efbcc4f4842ccc746d4db9 (glob)

#endif

  $ hg debugnodemap --check
  revision in index:   5002
  revision in nodemap: 5002