redesign for better IO performance
enhanced database seek-time by avoiding write operations at distant
positions of a database file. until now, a USEDC counter was written
at the head-section of a kelondroRecords database file (which is the
basic data structure of all kelondro database files) to store the
actual number of records that are contained in the database. Now, this
value is computed from the database file size. This is either done
only once at start-time, or continuously when run in asserts enabled.
The counter is then updated only in RAM, and written at close of the
file. If the close fails, the correct number can be computed from the
file size, and if this is not equal to the stored number it is a strong
evidence that YaCY was not shut down properly.
To preserve consistency, the complete storage-routine had to be re-written.
Another change enhances read of nodes in some cases, where the data-tail
can be read together with the data-head. This saves another IO lookup during
each DB node fetch.
Includes also many small bugfixes.
IF ANYTHING GOES WRONG, ALL YOUR DATA IS LOST: PLEASE MAKE A BACK-UP
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@3375 6c8d7289-2bf4-0310-a012-ef5d649a1542
- added some settings and statistics for url-fetcher 'server'-mode
- added own stack for fetchable URLs
- added possibility to fill stack via shift from peer's queues, via POST (addurls=$count and url$num=$url) or via file-upload
- added "htroot" to classpath of linux start-script
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@3370 6c8d7289-2bf4-0310-a012-ef5d649a1542
- sent URLs are taken off the limit-stack (of the global crawl trigger) (may be moved somewhere else in future versions)
- added option to set the requested chunk-size
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@3367 6c8d7289-2bf4-0310-a012-ef5d649a1542
various checks like the blacklist check or the robots.txt disallow check are now
done by a separate thread to unburden the indexer thread(s)
TODO: maybe we have to introduce a threadpool here if it turn out that this single
thread is a bottleneck because of the time consuming robots.txt downloads
*) improved index transfer
The index selection and transmission is done in parallel now to improve index
transfer performance.
TODO: maybe we could speed up performance by unsing multiple transmission threads in
parallel instead of only a single one.
*) gzip encoded post requests
it is now configureable if a gzip encoded post request should be send on
intex transfer/distribution
*) storage Peer (very experimentell and not optimized yet)
Now it's possible to send the result of the yacy indexer thread to a remote peer
istead of storing the indexed words locally.
This could be done by setting the property "storagePeerHash" in the yacy config file
- Please note that if the index transfer fails, the index ist stored locally.
- TODO: currently this index transfer is done by the indexer thread.
To seedup the indexer
a) this transmission should be done in parallel and
b) multiple chunks should be bundled and transfered together
*) general performance improvements
- better memory cleanup after http request processing has finished
- replacing some string concatenations with stringBuffers
- replacing BufferedInputStreams with serverByteBuffer
- replacing vectors with arraylists wherever possible
- replacing hashtables with hashmaps wherever possible
This was done because function calls to verctor or hashtable functions
take 3 time longer than calls to functions of arraylists or hashmaps.
TODO: we should take a look on the class serverObject which is inherited from hashmap
Do we realy need a synchronization for this class?
TODO: replace arraylists with linkedLists if random access to the list elements is not needed
*) Robots Parser supports if-modified-since downloads now
If the downloaded robots.txt file is older than 7 days the robots parser tries to
download the robots.txt with the if-modified-since header to avoid unnecessary downloads
if the file was not changed. Additionally the ETag header is used to detect changes.
*) Crawler: better handling of unsupported mimeTypes + FileExtension
*) Bugfix: plasmaWordIndexEntity was not closed correctly in
- query.java
- plasmaswitchboard.java
*) function minimizeUrlDB added to yacy.java
this function tests the current urlHashDB for unused urls
ATTENTION: please don't use this function at the moment because
it causes the wordIndexDB to flush all words into the
word directory!
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@853 6c8d7289-2bf4-0310-a012-ef5d649a1542
Now it's easier to determine which class really uses which other class*) Reogranizing Import Statements
git-svn-id: https://svn.berlios.de/svnroot/repos/yacy/trunk@83 6c8d7289-2bf4-0310-a012-ef5d649a1542
