Diff	ID	Description	Created	Lint	Unit
Base		Base
Diff 1	19158		Jan 11 2020, 12:03 PM	★	★
Diff 2	19175		Jan 13 2020, 10:06 AM	★	★
Diff 3	19754		Jan 31 2020, 10:28 AM	★	★
Diff 4	19784		Jan 31 2020, 5:58 PM	★	★
Diff 5	19828		Feb 2 2020, 3:17 AM	★	★
Diff 6	19886		Feb 4 2020, 7:24 PM	★	★
Diff 7	20106	rHG2b72c4ff8ed11cad198bcd60c46a05d94292ce0b	Jan 15 2020, 9:47 AM	★	★

Status	Author	Revision
Closed	marmoute	D7894 nodemap: introduce an option to use mmap to read the nodemap mapping
Closed	marmoute	D7893 nodemap: update the index with the newly written data (when appropriate)
Closed	marmoute	D7892 nodemap: never read more than the expected data amount
Closed	marmoute	D7891 nodemap: write new data from the expected current data length
Closed	marmoute	D7890 nodemap: double check the source docket when doing incremental update
Closed	marmoute	D7889 nodemap: track the total and unused amount of data in the rawdata file
Closed	marmoute	D7888 nodemap: track the maximum revision tracked in the nodemap
Closed	marmoute	D7887 nodemap: add a flag to dump the details of the docket
Closed	marmoute	D7886 nodemap: introduce append-only incremental update of the persisten data
Closed	marmoute	D7885 nodemap: keep track of the docket for loaded data
Closed	marmoute	D7884 nodemap: introduce an explicit class/object for the docket
Closed	marmoute	D7883 nodemap: keep track of the ondisk id of nodemap blocks
Closed	marmoute	D7847 nodemap: provide the on disk data to indexes who support it
Closed	marmoute	D7846 nodemap: all check that revision and nodes match in the nodemap
Closed	marmoute	D7845 nodemap: add basic checking of the on disk nodemap content
Closed	marmoute	D7844 nodemap: code to parse the persistent binary nodemap data
Closed	marmoute	D7843 nodemap: move the iteratio inside the Block object
Closed	marmoute	D7842 nodemap: use an explicit "Block" object in the reference implementation
Closed	marmoute	D7841 nodemap: add a optional `nodemap_add_full` method on indexes
Closed	marmoute	D7840 nodemap: add a (python) index class for persistent nodemap testing
Closed	marmoute	D7839 nodemap: delete older raw data file when creating a new ones
Closed	marmoute	D7838 nodemap: use an intermediate "docket" file to carry small metadata
Closed	marmoute	D7837 nodemap: only use persistent nodemap for non-inlined revlog
Closed	marmoute	D7836 nodemap: add a function to read the data from disk
Closed	marmoute	D7835 nodemap: write nodemap data on disk
Closed	marmoute	D7834 nodemap: have some python code writing a nodemap in persistent binary form

Diff 20106

mercurial/revlogutils/nodemap.py

	# nodemap.py - nodemap related code and utilities			# nodemap.py - nodemap related code and utilities
	#			#
	# Copyright 2019 Pierre-Yves David <pierre-yves.david@octobus.net>			# Copyright 2019 Pierre-Yves David <pierre-yves.david@octobus.net>
	# Copyright 2019 George Racinet <georges.racinet@octobus.net>			# Copyright 2019 George Racinet <georges.racinet@octobus.net>
	#			#
	# This software may be used and distributed according to the terms of the			# This software may be used and distributed according to the terms of the
	# GNU General Public License version 2 or any later version.			# GNU General Public License version 2 or any later version.

	from __future__ import absolute_import			from __future__ import absolute_import

				import os
	import struct			import struct

	from .. import (			from .. import (
	error,			error,
	node as nodemod,			node as nodemod,
	pycompat,			pycompat,
	)			)


	class NodeMap(dict):			class NodeMap(dict):
	def __missing__(self, x):			def __missing__(self, x):
	raise error.RevlogError(b'unknown node: %s' % x)			raise error.RevlogError(b'unknown node: %s' % x)


	def persisted_data(revlog):			def persisted_data(revlog):
	"""read the nodemap for a revlog from disk"""			"""read the nodemap for a revlog from disk"""
	if revlog.nodemap_file is None:			if revlog.nodemap_file is None:
	return None			return None
	return revlog.opener.tryread(revlog.nodemap_file)			pdata = revlog.opener.tryread(revlog.nodemap_file)
				if not pdata:
				return None
				offset = 0
				(version,) = S_VERSION.unpack(pdata[offset : offset + S_VERSION.size])
				if version != ONDISK_VERSION:
				return None
				offset += S_VERSION.size
				(uuid_size,) = S_HEADER.unpack(pdata[offset : offset + S_HEADER.size])
				offset += S_HEADER.size
				uid = pdata[offset : offset + uuid_size]

				filename = _rawdata_filepath(revlog, uid)
				return revlog.opener.tryread(filename)


	def setup_persistent_nodemap(tr, revlog):			def setup_persistent_nodemap(tr, revlog):
	"""Install whatever is needed transaction side to persist a nodemap on disk			"""Install whatever is needed transaction side to persist a nodemap on disk

	(only actually persist the nodemap if this is relevant for this revlog)			(only actually persist the nodemap if this is relevant for this revlog)
	"""			"""
	if revlog._inline:			if revlog._inline:
	if getattr(revlog, 'filteredrevs', ()):			if getattr(revlog, 'filteredrevs', ()):
	raise error.ProgrammingError(			raise error.ProgrammingError(
	"cannot persist nodemap of a filtered changelog"			"cannot persist nodemap of a filtered changelog"
	)			)
	if revlog.nodemap_file is None:			if revlog.nodemap_file is None:
	msg = "calling persist nodemap on a revlog without the feature enableb"			msg = "calling persist nodemap on a revlog without the feature enableb"
	raise error.ProgrammingError(msg)			raise error.ProgrammingError(msg)
	data = persistent_data(revlog.index)			data = persistent_data(revlog.index)
				uid = _make_uid()
				datafile = _rawdata_filepath(revlog, uid)
	# EXP-TODO: if this is a cache, this should use a cache vfs, not a			# EXP-TODO: if this is a cache, this should use a cache vfs, not a
	# store vfs			# store vfs
	with revlog.opener(revlog.nodemap_file, b'w') as f:			with revlog.opener(datafile, b'w') as fd:
	f.write(data)			fd.write(data)
				# EXP-TODO: if this is a cache, this should use a cache vfs, not a
				# store vfs
				with revlog.opener(revlog.nodemap_file, b'w', atomictemp=True) as fp:
				fp.write(_serialize_docket(uid))
	# EXP-TODO: if the transaction abort, we should remove the new data and			# EXP-TODO: if the transaction abort, we should remove the new data and
	# reinstall the old one. (This will be simpler when the file format get a			# reinstall the old one.
	# bit more advanced)

				### Nodemap docket file
				#
				# The nodemap data are stored on disk using 2 files:
				#
				# * a raw data files containing a persistent nodemap
				# (see `Nodemap Trie` section)
				#
				# * a small "docket" file containing medatadata
				#
				# While the nodemap data can be multiple tens of megabytes, the "docket" is
				# small, it is easy to update it automatically or to duplicated its content
				# during a transaction.
				#
				# Multiple raw data can exist at the same time (The currently valid one and a
				# new one beind used by an in progress transaction). To accomodate this, the
				# filename hosting the raw data has a variable parts. The exact filename is
				# specified inside the "docket" file.
				#
				# The docket file contains information to find, qualify and validate the raw
				# data. Its content is currently very light, but it will expand as the on disk
				# nodemap gains the necessary features to be used in production.

				# version 0 is experimental, no BC garantee, do no use outside of tests.
				ONDISK_VERSION = 0

				S_VERSION = struct.Struct(">B")
				S_HEADER = struct.Struct(">B")

				ID_SIZE = 8


				def _make_uid():
				"""return a new unique identifier.

				The identifier is random and composed of ascii characters."""
				return nodemod.hex(os.urandom(ID_SIZE))


				def _serialize_docket(uid):
				"""return serialized bytes for a docket using the passed uid"""
				data = []
				data.append(S_VERSION.pack(ONDISK_VERSION))
				data.append(S_HEADER.pack(len(uid)))
				data.append(uid)
				return b''.join(data)


				def _rawdata_filepath(revlog, uid):
				"""The (vfs relative) nodemap's rawdata file for a given uid"""
				prefix = revlog.nodemap_file[:-2]
				return b"%s-%s.nd" % (prefix, uid)


	### Nodemap Trie			### Nodemap Trie
	#			#
	# This is a simple reference implementation to compute and persist a nodemap			# This is a simple reference implementation to compute and persist a nodemap
	# trie. This reference implementation is write only. The python version of this			# trie. This reference implementation is write only. The python version of this
	# is not expected to be actually used, since it wont provide performance			# is not expected to be actually used, since it wont provide performance
	# improvement over existing non-persistent C implementation.			# improvement over existing non-persistent C implementation.

tests/test-persistent-nodemap.t

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


	$ hg init test-repo			$ hg init test-repo
	$ cd test-repo			$ cd test-repo
	$ cat << EOF >> .hg/hgrc			$ cat << EOF >> .hg/hgrc
	> [experimental]			> [experimental]
	> exp-persistent-nodemap=yes			> exp-persistent-nodemap=yes
	> EOF			> EOF
	$ hg debugbuilddag .+5000			$ hg debugbuilddag .+5000
				$ f --size .hg/store/00changelog.n
				.hg/store/00changelog.n: size=18
	$ hg debugnodemap --dump-new \| f --sha256 --size			$ hg debugnodemap --dump-new \| f --sha256 --size
	size=122880, sha256=b961925120e1c9bc345c199b2cc442abc477029fdece37ef9d99cbe59c0558b7			size=122880, sha256=b961925120e1c9bc345c199b2cc442abc477029fdece37ef9d99cbe59c0558b7
	$ hg debugnodemap --dump-disk \| f --sha256 --bytes=256 --hexdump --size			$ hg debugnodemap --dump-disk \| f --sha256 --bytes=256 --hexdump --size
	size=122880, sha256=b961925120e1c9bc345c199b2cc442abc477029fdece37ef9d99cbe59c0558b7			size=122880, sha256=b961925120e1c9bc345c199b2cc442abc477029fdece37ef9d99cbe59c0558b7
	0000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff \|................\|			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 \|................\|			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 \|................\|			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 \|................\|			0030: ff ff ff ff ff ff ed b3 ff ff ff ff ff ff ff ff \|................\|

			Path	Packages
M			mercurial/revlogutils/nodemap.py (82 lines)
M			tests/test-persistent-nodemap.t (2 lines)

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nodemap: use an intermediate "docket" file to carry small metadata
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mercurial/revlogutils/nodemap.py

tests/test-persistent-nodemap.t

This is an archive of the discontinued Mercurial Phabricator instance.

nodemap: use an intermediate "docket" file to carry small metadataClosedPublic

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Diff 20106

mercurial/revlogutils/nodemap.py

tests/test-persistent-nodemap.t

nodemap: use an intermediate "docket" file to carry small metadata
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