rust-nodemap: accounting for dead blocks
By the very append-only nature of the `NodeTree`, inserting
new blocks has the effect of making some of the older ones
useless as they become unreachable.
Therefore some automatic housekeeping will need to be provided.
This is standard procedure in the word of databases, under names
such as "repack" or "vacuum".
The new `masked_readonly_blocks()` will provide callers with
useful information to decide if the nodetree is ripe for
repacking, but all the `NodeTree` can provide is how many
blocks have been masked in the currently mutable part. Analysing
the readonly part would be way too long to do it for each
transaction and defeat the whole purpose of nodemap persistence.
Serializing callers (from the Python layer) will get this figure
before each extraction and maintain an aggregate counter of
unreachable blocks separately.
Note: at this point, the most efficient repacking is just to restart
afresh with a full rescan.
Differential Revision: https://phab.mercurial-scm.org/D8097
#require no-windows
$ . "$TESTDIR/remotefilelog-library.sh"
$ hg init master
$ grep generaldelta master/.hg/requires
generaldelta
$ cd master
preferuncompressed = False so that we can make both generaldelta and non-generaldelta clones
$ cat >> .hg/hgrc <<EOF
> [remotefilelog]
> server=True
> [experimental]
> bundle2-exp = True
> [server]
> preferuncompressed = False
> EOF
$ echo x > x
$ hg commit -qAm x
$ cd ..
$ hgcloneshallow ssh://user@dummy/master shallow-generaldelta -q --pull --config experimental.bundle2-exp=True
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
$ grep generaldelta shallow-generaldelta/.hg/requires
generaldelta
$ hgcloneshallow ssh://user@dummy/master shallow-plain -q --pull --config format.usegeneraldelta=False --config format.generaldelta=False --config experimental.bundle2-exp=True
$ grep generaldelta shallow-plain/.hg/requires
[1]
$ cd master
$ echo a > a
$ hg commit -qAm a
pull from generaldelta to generaldelta
$ cd ../shallow-generaldelta
$ hg pull -u
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files
new changesets 2fbb8bb2b903
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
push from generaldelta to generaldelta
$ echo b > b
$ hg commit -qAm b
$ hg push
pushing to ssh://user@dummy/master
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files
pull from generaldelta to non-generaldelta
$ cd ../shallow-plain
$ hg pull -u
pulling from ssh://user@dummy/master
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 0 changes to 0 files
new changesets 2fbb8bb2b903:d6788bd632ca
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
1 files fetched over 1 fetches - (1 misses, 0.00% hit ratio) over *s (glob)
push from non-generaldelta to generaldelta
$ echo c > c
$ hg commit -qAm c
$ hg push
pushing to ssh://user@dummy/master
searching for changes
remote: adding changesets
remote: adding manifests
remote: adding file changes
remote: added 1 changesets with 1 changes to 1 files