This is a very complex migration: many classes had been renamed or
removed, dependencies changed and the solr index type is now aligned to
be a solr cloud repository.
Together with the Solr 5.2 library update, one other dependent library
had been updated as well: httpclient 4.4->4.4.1
Older indexes are migrated from 4_10 to 5_2. However, the new index
structure is more efficient and we recommend to re-index everything.
Please use the index export before you do the update to a large
surrogate xml file. After the update, start with an empty index and then
initialize this with your dump.
servlet and moved it to a new /IndexExport_p.html servlet. This servlet
is now more prominent linked in the main menu under Production -> Index
Export/Import
export function is also now the default export option. The export file
format for a full solr export is very similar to a solr search result
xml, only the <lst name="responseHeader"> tag is missing.
The exported xml has a special line termination feature: all documents
will be exported into a single line without any CR in between. That
means that every document is completely inside a single line. While this
is not readable at all for humans, it is very useful for linux line
processing scripts, like grep. Using grep it will be easy to select
single documents which match for a given pattern.
Such dumps shall be importable with the DATA/SURROGATE/in import
function, but that import is not yet adopted to the new file format.
hold a date for each URL to record when a url was first seen. This is
then used to overwrite the modification date for urls upon recrawl in
case that the first-seen date is before the latest document date. This
behaviour is necessary due to the common behaviour of content management
systems which attach always the current date to all documents. Using the
firstSeen database it is possible to approximate a real first document
creation date in case that the crawler starts frequently for the same
domain. As a result the search results ordered by date have a much
better quality and the usage of YaCy as search agent for latest news has
a better quality.
introduced, it was also used for search facets. The generic search
facets are now deduced from generic solr fields which makes jena as tool
for facet semantics superfluous.
- refactored all code which uses URIMetadataRow as standard for word
hash length and word hash ordering and moved that to the class 'Word',
becuase the class URIMetadataRow defined the old metadata data structure
and should be superfluous in the future
- removed unused methods from URIMetadataRow as preparation for further
removal of that class
as path for solr index dumps (instead of the SEGMENTS path). This will
make a maintenance of index backups easier. It will also provide a tool
to migrate from an freeworld index to a webportal index.
which had a problem because of badly used concurrency.
This fix also caused a redesign of the whole host deletion process.
This should fix bug http://bugs.yacy.net/view.php?id=250
all unique links! This made it necessary, that a large portion of the
parser and link processing classes must be adopted to carry a different
type of link collection which carry a property attribute which are
attached to web anchors.
- introduction of a new URL class, AnchorURL
- the other url classes, DigestURI and MultiProtocolURI had been renamed
and refactored to fit into a new document package schema, document.id
- cleanup of net.yacy.cora.document package and refactoring
in intranets and the internet can now choose to appear as Googlebot.
This is an essential necessity to be able to compete in the field of
commercial search appliances, since most web pages are these days
optimized only for Google and no other search platform any more. All
commercial search engine providers have a built-in fake-Google User
Agent to be able to get the same search index as Google can do. Without
the resistance against obeying to robots.txt in this case, no
competition is possible any more. YaCy will always obey the robots.txt
when it is used for crawling the web in a peer-to-peer network, but to
establish a Search Appliance (like a Google Search Appliance, GSA) it is
necessary to be able to behave exactly like a Google crawler.
With this change, you will be able to switch the user agent when portal
or intranet mode is selected on per-crawl-start basis. Every crawl start
can have a different user agent.
jdk-based logger tend to block
at java.util.logging.Logger.log(Logger.java:476) in concurrent
environments. This makes logging a main performance issue. To overcome
this problem, this is a add-on to jdk logging to put log entries on a
concurrent message queue and log the messages one by one using a
separate process.
- FTPClient uses the concurrent logging instead of the log4j logger
API recording for this method so it can be repeated automatically. The
index dump generation is now also available for API recording. Added
some synchronization in backend which was necessary for this.
Because the index size is now provided by solr, and the only way to do
that is a match for [* TO *], a size computation is quite complex and
time-consuming. Therefore this patch prevents that the method is called
at all and if necessary puts a DOS-preventing barrier in front of it.
The default schema uses only some of them and the resting search index
has now the following properties:
- webgraph size will have about 40 times as much entries as default
index
- the complete index size will increase and may be about the double size
of current amount
As testing showed, not much indexing performance is lost. The default
index will be smaller (moved fields out of it); thus searching
can be faster.
The new index will cause that some old parts in YaCy can be removed,
i.e. specialized webgraph data and the noload crawler. The new index
will make it possible to:
- search within link texts of linked but not indexed documents (about 20
times of document index in size!!)
- get a very detailed link graph
- enhance ranking using a complete link graph
To get the full access to the new index, the API to solr has now two
access points: one with attribute core=collection1 for the default
search index and core=webgraph to the new webgraph search index. This is
also avaiable for p2p operation but client access is not yet
implemented.
structure, but is not filled yet. To have the opportunity of a second
core, multi-core functionality had to be implemented to the
deep-embedded solr:
- migrated the solr_40 directory content to a subdirectory
'collection1'; the previously used default core is now called
collection1
- added solr_40/webgraph subdirectory as second core
- added a servlet configuration for the second core 'webgraph' in
/IndexSchema_p.html
- added instance handling as addition to solr connections: all solr
connectors are now instances of an solr 'instance' object; this required
a complete re-design of the solr embedding
- migrated also caching and sharding ontop of new instance handling
- migrated the search apis to handle now the access to a specific core,
the default core named 'collection1'
- migrated the remote solr search interface to access shards of cores;
for the yacy remote search the default core is now called 'solr'; using
the peer address as solr address
- migrated the solr backup and restore process: old backups cannot be
used after this migration!
- redesign of solr instance handling in all methods which access the
instances: they cannot hold copies of these instances any more; the must
retrieve the actuall connection object every time they want to write to
it (this solves also some bugs when switching the index/network)
- added another schema 'solr.webgraph.schema', the old solr.keys.list is
replaced by solr.collection.schema
metadata and old rwi and for the citation index. The important
advancement is the separation of the citation index deletion because
that index is responsible for the linkdepth calculation. Now a search
index can be deleted without the citation index and that should cause
that less clickdepths must be post-processed.
deleted which are selected by a crawl filter (host or subpath)
- site crawl used this option be default now
- made option to deleteDomain() concurrency
superfluous. The target is to make a solr document as the core of YaCy
documents which would cause that many conversions can be removed. On the
way to this target the Equivalence of URIMetadataRow and URIMetadataNode
had to be removed to expose the usage of the old URIMetadataRow data
structure.
This refactoring already removes unneccessary conversions and should
make memory usage during indexing lower.
URIMetadataNode which creates the opportunity to access Solr objects
directly and use their information richness
- lazy initialization of the URIMetadataNode object - should cause less
computation and memory usage during search.
- removed dead code
MultiProtocolURI during normalform computation because that should
always be done and also be done during initialization of the
MultiProtocolURI Object. The new normalform method takes only one
argument which should be 'true' unless you know exactly what you are
doing.
IndexControlURLs where it appears more naturally. Because the RWI
administration is less important in the presence of Solr, the
IndexControlURL is now the default servlet when the Index Administration
button on the main menu is selected.
- reduced danger that a non-existing RWI database causes NPEs
- added Solr queries to did-you-mean: this makes it possible that our
did-you-mean algorithm works together with only Solr and without RWIs
Michael Peter Christen