X-Git-Url: https://git.mdrn.pl/pylucene.git/blobdiff_plain/a2e61f0c04805cfcb8706176758d1283c7e3a55c..aaeed5504b982cf3545252ab528713250aa33eed:/lucene-java-3.4.0/lucene/contrib/misc/src/java/overview.html diff --git a/lucene-java-3.4.0/lucene/contrib/misc/src/java/overview.html b/lucene-java-3.4.0/lucene/contrib/misc/src/java/overview.html deleted file mode 100644 index bd87055..0000000 --- a/lucene-java-3.4.0/lucene/contrib/misc/src/java/overview.html +++ /dev/null @@ -1,77 +0,0 @@ - - - - - miscellaneous - - - - -

Misc Tools

- -The misc package has various tools for splitting/merging indices, -changing norms, finding high freq terms, and others. - -

DirectIOLinuxDirectory

- -

-NOTE: This uses C++ sources (accessible via JNI), which you'll -have to compile on your platform. Further, this is a very -platform-specific extensions (runs only on Linux, and likely only on -2.6.x kernels). - -

-DirectIOLinuxDirectory is a Directory implementation that bypasses the -OS's buffer cache for any IndexInput and IndexOutput opened through it -(using the linux-specific O_DIRECT flag). - -

-Note that doing so typically results in bad performance loss! You -should not use this for searching, but rather for indexing (or maybe -just merging during indexing), to avoid evicting useful pages from the -buffer cache. - -See here -for details. - -Steps to build: -

- -

-To use this, you'll likely want to make a custom subclass of -FSDirectory that only opens direct IndexInput/Output for merging. One -hackish way to do this is to check if the current thread's name starts -with "Lucene Merge Thread". Alternatively, you could use this Dir as -is for all indexing ops, but not for searching. - -

-NativePosixUtil.cpp/java also expose access to the posix_madvise, -madvise, posix_fadvise functions, which are somewhat more cross -platform than O_DIRECT, however, in testing (see above link), these -APIs did not seem to help prevent buffer cache eviction. - - -