We now have a very useful annotation to mark features or parameters as
experimental. Let's use it! This commit replaces some custom text warnings with
this annotation and adds this annotation to some existing features/parameters:
- inner_hits (unreleased yet)
- terminate_after (released in 1.4)
- per-bucket doc count errors in the terms agg (released in 1.4)
I also tagged with this annotation settings which should either be not needed
(like the ability to evict entries from the filter cache based on time) or that
are too deep into the way that Elasticsearch works like the Directory
implementation or merge settings.
Close#9563
The current "checkindex" on startup is very very expensive. This is
like running one of the old school hard drive diagnostic checkers and
usually not a good idea.
But we can do a CRC32 verification of files. We don't even need to
open an indexreader to do this, its much more lightweight.
This option (as well as the existing true/false) are randomized in
tests to find problems.
Also fix bug where use of the current option would always leak
an indexwriter lock.
Closes#9183
Upgrades lucene to latest, and supports the BEST_COMPRESSION parameter
now supported (with backwards compatibility, etc) in Lucene.
This option uses deflate, tuned for highly compressible data.
index.codec::
The default value compresses stored data with LZ4 compression, but
this can be set to best_compression for a higher compression ratio,
at the expense of slower stored fields performance.
IMO its safest to implement as a named codec here, because ES already
has logic to handle this correctly, and because its unrealistic to have
a plethora of options to Lucene's default codec... we are practically
limited in Lucene to what we can support with back compat, so I don't
think we should overengineer this and add additional unnecessary plumbing.
See also:
https://issues.apache.org/jira/browse/LUCENE-5914https://issues.apache.org/jira/browse/LUCENE-6089https://issues.apache.org/jira/browse/LUCENE-6090https://issues.apache.org/jira/browse/LUCENE-6100Closes#8863
This documentation was dangerous because it felt like it was possible to gain
substantial performance by just switching the codec of the index.
However, non-default codecs are dangerous to use since they are not supported
in terms of backward compatibility, and most improvements that they bring have
been folded into the default codec anyway (for example, the default codec
"pulses" postings lists that contain a single document).
Adrien Grand
Robert Muir
Clinton Gormley
Simon Willnauer
Lee Hinman