view tests/test-issue612.t @ 16363:2cdd7e63211b

parsers: incrementally parse the revlog index in C

We only parse entries in a revlog index file when they are actually
needed, and cache them when first requested.

This makes a huge difference to performance on large revlogs when
accessing the tip revision or performing a handful of numeric lookups
(very common cases).  For instance, "hg --time tip --template {node}"
on a tree with 300,000 revs takes 0.15 before, 0.02 after.

Even for revlog-intensive operations (e.g. running "hg log" to
completion), the lazy approach is about 1% faster than the eager
parse_index2.

http://mercurial.selenic.com/bts/issue612

  $ hg init
  $ mkdir src
  $ echo a > src/a.c
  $ hg ci -Ama
  adding src/a.c

  $ hg mv src source
  moving src/a.c to source/a.c (glob)

  $ hg ci -Ammove

  $ hg co -C 0
  1 files updated, 0 files merged, 1 files removed, 0 files unresolved

  $ echo new > src/a.c
  $ echo compiled > src/a.o
  $ hg ci -mupdate
  created new head

  $ hg status
  ? src/a.o

  $ hg merge
  merging src/a.c and source/a.c to source/a.c
  0 files updated, 1 files merged, 0 files removed, 0 files unresolved
  (branch merge, don't forget to commit)

  $ hg status
  M source/a.c
  R src/a.c
  ? src/a.o