This organizes all urls to be loaded in separate queues for each host.
Each host separates the crawl depth into it's own queue. The primary
rule for urls taken from any queue is, that the crawl depth is minimal.
This produces a crawl depth which is identical to the clickdepth.
Furthermorem the crawl is able to create a much better balancing over
all hosts which is fair to all hosts that are in the queue.
This process will create a very large number of files for wide crawls in
the QUEUES folder: for each host a directory, for each crawl depth a
file inside the directory. A crawl with maxdepth = 4 will be able to
create 10.000s of files. To be able to use that many file readers, it
was necessary to implement a new index data structure which opens the
file only if an access is wanted (OnDemandOpenFileIndex). The usage of
such on-demand file reader shall prevent that the number of file
pointers is over the system limit, which is usually about 10.000 open
files. Some parts of YaCy had to be adopted to handle the crawl depth
number correctly. The logging and the IndexCreateQueues servlet had to
be adopted to show the crawl queues differently, because the host name
is attached to the port on the host to differentiate between http,
https, and ftp services.
- removed the default version blacklist regex from init (for future versions)
!!! left existing update blacklist setting untouched !!!
(existing installation wanting autoupdate for 1.71 need to change blacklist in ConfigUpdate_p.html)
- moved old blacklist patch to migration.java
stack on html tag objects, not using a recursive parse-again method
which may cause bad performance and huge memory allocation. The new
method also produced better parsed image objects with exact anchor text
references.
- added order option to solr queries to be able to retrieve document
lists in specific order, here: link length
- added HyperlinkEdge class which manages the link structure
- integrated the HyperlinkEdge class into clickdepth computation
- extended the linkstructure.json servlet to show also the clickdepth
and other statistic information
- not doing an optimization will likely cause a too many files exception
- without optimization performance will be even worse which would
prevent optimization in the future as well (prevent a deadlock
situation)
in case that a too many open files error exist. In such a case, the file
yacy00.log does not exist but only the file yacy00.log.lck.
In the long term a different solution should be addressed.
It's nowhere explained or declared, but since some time we follow the
schema that uneven version numbers are used for development versions and
even numbers for release versions. That concept may change sometime but
this is used at this time to distinguish development from main.
reger