instead of TreeMaps)
- enhanced memory footprint of database indexes (by introduction of
optimize calls)
- optimize calls shrink the amount of used memory for index sets if they
are not changed afterwards any more
The resource observer is now able to recognize free disk space AND
available space for YaCy. The amount of space which is assigned for YaCy
are defined in new settings in the configuration file.
Furthermore, there is now a cleanup process which deletes files in case
that an autodelete is activated. The autodelete is now BY DEFAULT ON if
the disk space is low, which means that YaCy starts to delete documents
when the disk is full!
- 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
where the size() and isEmpty() method is used only for statistics, which
happens at many locations in YaCy. If these methods are used for
structual reasons (like accessing the last element in an array) then it
may fail or cause other problems. As far as visible, this is not the
case.
- transformed log lines to String before they are stored because the
storage space is about 1:250 (45kb for one line before transformation,
180 bytes afterwards)
- this saves up to 10MB RAM so we can increase the number of lines to
1000 again.
the right content domain (i.e. identifying that it is an image, text
etc.) because it used the file extension and not an existing mime type
assignment.
- fixed the new setting that images shall be loaded for a better image
search.
- both fixes together makes it now possible to crawl
commons.wikimedia.org which makes use of 'funny' document names (i.e.
ending with .jpg while the document is html)
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
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
While the values for the reference evaluation are computed, also a
backlink-structure can be discovered and written to the index as well.
The host browser has been extended to show such backlinks to each
presented links. The host browser therefore can now show an information
where an document is linked. The new citation reference is computed as
likelyhood for a random click path with recursive usage of previously
computed likelyhood. This process is repeated until the likelyhood
converges to a specific number. This number is then normalized to a
ranking value CRn, 0<=CRn<=1. The value CRn can therefore be used to
rank popularity within intra-domain link structures.
id to be tested, but with a collection of ids. This will cause only a
single call to solr instead of many. The result is a much better
performace when testing the existence of many urls. The effect should
cause very much less IO during index transmission, both on sender and
receiver side.
process counter if an blocking thread dies. Added also a new column in
PerformanceConcurrency_p servlet to show the actual number of concurrent
processes.
- check geolocation coordinates and accept only those, which are
well-formed
- the solr push process does not stop crawling any more if after 20
requests to Solr Solr does not accept the record. Instead, a severe log
entry asks the user to create a bug request
adjusted to smaller and 1-core devices.
- the workflow processor now starts no process at all. these are started
as soon as parser/condenser/indexing queues are filled.
- better abstraction
references_external_i and references_exthosts_i. These can be used to
count and evaluate the number of external links to every web page. An
experimental ranking function can be i.e.:
div(add(references_internal_i,product(references_external_i,references_exthosts_i)),add(clickdepth_i,1))
- memory allocation problem in RowCollection: if memory is too low, do
not to try to increase by 1 because this leads to very long execution
time and at the end to the same OOM as if we allocate the memory at the
moment we need it even if the resource observer states that this memory
is not there. To compensate this, the increase size is reduced.
- an existing ranking servlet for solr was extended. It is now possible
to set boost values for fields, boost functions and boost queries.
- The ranking can have different instances, but currently only the first
one is used
- added an abstraction layer for fields which can be used for search and
those fields can be edited in the solr ranking configruation
- the ranking value from solr within the field score is used to combine
remote search requests, which all are created using the same locally
defined boost values
- reduced the number of fields which are used for search (makes it
faster)
- replaced some text fields by string fields (makes indexing faster)
- removed classes which had no use
- made a large number of experiments for a better ranking and created a
temporary setting which prefers hits inside titles
- adjusted also the RWI-based ranking computation to 'prefer title'
- made special cases like for portal search where no post-processing and
post-ranking is wanted: this keeps the original ranking order as done by
Solr
- fixed many bugs with old settings for ranking
- removed 'worker' processes
- no internal time-out behaviour: methods either are successful or
return null
- waiting is only done on top-level
- removed snippet-production; this is replaced by solr snippets
- removed statistics based on solr size queries (they had been VERY
long); the statistics (like suggestions or tag cloud) are now again
based on the old but very fast RWI index. In portal or intranet mode the
RWI index is usually switched off; if you like to have statistics again
then you must switch on the rwis again in this mode.
- fixed many bugs regarding correct page counter
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
- migrates all entries in old urldb
Metadata coordinate (lat / lon) NumberFormatException still relative often (see excerpt below),
- added try/catch for URIMetadataRow (seems not to be needed in URIMetaDataNode, as Solr internally checks for number format)
- removed possible typ conversion for lat() / lon() comparison with 0.0f, changed to 0.0 (leaving it to the compiler/optimizer to choose number format)
current log excerpt for NumberFormatException:
W 2013/01/14 00:10:07 StackTrace For input string: "-"
java.lang.NumberFormatException: For input string: "-"
at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
at java.lang.Double.parseDouble(Unknown Source)
at net.yacy.kelondro.data.meta.URIMetadataRow$Components.lon(URIMetadataRow.java:525)
at net.yacy.kelondro.data.meta.URIMetadataRow.lon(URIMetadataRow.java:279)
at net.yacy.search.index.SolrConfiguration.metadata2solr(SolrConfiguration.java:277)
at net.yacy.search.index.Fulltext.putMetadata(Fulltext.java:329)
at transferURL.respond(transferURL.java:152)
...
Caused by: java.lang.NumberFormatException: For input string: "-"
at sun.misc.FloatingDecimal.readJavaFormatString(Unknown Source)
at java.lang.Double.parseDouble(Unknown Source)
at net.yacy.kelondro.data.meta.URIMetadataRow$Components.lon(URIMetadataRow.java:525)
at net.yacy.kelondro.data.meta.URIMetadataRow.lon(URIMetadataRow.java:279)
at net.yacy.search.index.SolrConfiguration.metadata2solr(SolrConfiguration.java:277)
at net.yacy.search.index.Fulltext.putMetadata(Fulltext.java:329)
at transferURL.respond(transferURL.java:152)
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.
This attribute can be used for ranking and for other purpose (demand by
customer)
The click depth is computed in two steps:
- during indexing the current fill-state of the reverse link index is
used to backtrack the current page to the root page. The length of that
backtrack is the clickdepth. But this does not discover the shortest
click depth. To get this, a second process to check again is needed
- added a process tag that can be used to do operations on the existing
index after a crawl; i.e. calculation the shortest clickpath. Added a
field to control this operation but not a method to operate on this.
- added a visualization of the clickpath length in the host browser
- an event type (once, regular) can be selected
- for this event type, a fixed time can be selected. This may be either
directly after startup or at one of the full hours at a day (==25
options)
The main point about this feature is the opportunity to start an action
directly after startup. That makes it possible to create YaCy
distributions which, after started at the first time, start to index
parts of the intranet/internet by itself.
This uses an enhanced version of the Nutch/Solr TextProfileSignatue.
As a result, a signature of the document is written to the solr search
index. Additionally for each time when a signature is written, it is
checked if the singature exists already in the index. If the signature
does not exist, the document is marked as unique. The unique attribute
can now be used to sort document lists and bring duplicates to the end
of a result list.
To enable this, a large portion of the search api to Solr had to be
changed. This affected mainly caching of 'exists' searches to enhance
the check for existing signatures and do this without actually doing a
solr query.
Because here the first time a long number is used as value in the Solr
store, also the value naming in the YaCySchema had to be adopted and
normalized. This caused that many files had to be changed.
the actual data which is fetched from solr.
- used the new field options to reduce generic options like getting the
load date or the count of search results. should increase overall speed
- used the new field options to reduce overhead in the host browser
during aquisition of links.
- used the field options to make checking of links in crawler faster
- if the crawler is paused, the crawl queue is not cleaned
- language default on missing lang property to "uk" (fix set to nothing)
- language set to TLD (added call to existing language calculation from TLD)
- coordinate number exception on possible lat/lon content of "NaN,NaN"
adjust Netbeans IDE classpath (for Solr/Lucene 4.0.0 jars)
Michael Peter Christen