========================
Whoosh 2.x release notes
========================
Whoosh 2.5
==========
* Whoosh 2.5 will read existing indexes, but segments created by 2.5 will not
be readable by older versions of Whoosh.
* As a replacement for field caches to speed up sorting, Whoosh now supports
adding a ``sortable=True`` keyword argument to fields. This makes Whoosh store
a sortable representation of the field's values in a "column" format
(which associates a "key" value with each document). This is more robust,
efficient, and customizable than the old behavior.
You should now specify ``sortable=True`` on fields that you plan on using to
sort or group search results.
(You can still sort/group on fields that don't have ``sortable=True``,
however it will use more RAM and be slower as Whoosh caches the field values
in memory.)
Fields that use ``sortable=True`` can avoid specifying ``stored=True``. The
field's value will still be available on ``Hit`` objects (the value will be
retrieved from the column instead of from the stored fields). This may
actually be faster for certain types of values.
* Whoosh will now detect common types of OR queries and use optimized read-ahead
matchers to speed them up by several times.
* Whoosh now includes pure-Python implementations of the Snowball stemmers and
stop word lists for various languages adapted from NLTK. These are available
through the :class:`whoosh.analysis.LanguageAnalyzer` analyzer or through the
``lang=`` keyword argument to the
:class:`~whoosh.fields.TEXT` field.
* You can now use the
:meth:`whoosh.filedb.filestore.Storage.create()` and
:meth:`whoosh.filedb.filestore.Storage.destory()`
methods as a consistent API to set up and tear down different types of
storage.
* Many bug fixes and speed improvements.
* Switched unit tests to use ``py.test`` instead of ``nose``.
* Removed obsolete ``SpellChecker`` class.
Whoosh 2.4
==========
* By default, Whoosh now assembles the individual files of a segment into a
single file when committing. This has a small performance penalty but solves
a problem where Whoosh can keep too many files open. Whoosh is also now
smarter about using mmap.
* Added functionality to index and search hierarchical documents. See
:doc:`/nested`.
* Rewrote the Directed Acyclic Word Graph implementation (used in spell
checking) to be faster and more space-efficient. Word graph files created by
previous versions will be ignored, meaning that spell checking may become
slower unless/until you replace the old segments (for example, by
optimizing).
* Rewrote multiprocessing indexing to be faster and simpler. You can now
do ``myindex.writer(procs=n)`` to get a multiprocessing writer, or
``myindex.writer(procs=n, multisegment=True)`` to get a multiprocessing
writer that leaves behind multiple segments, like the old MultiSegmentWriter.
(``MultiSegmentWriter`` is still available as a function that returns the
new class.)
* When creating ``Term`` query objects for special fields (e.g. NUMERIC or
BOOLEAN), you can now use the field's literal type instead of a string as the
second argument, for example ``Term("num", 20)`` or ``Term("bool", True)``.
(This change may cause problems interacting with functions that expect
query objects to be pure textual, such as spell checking.)
* All writing to and reading from on-disk indexes is now done through "codec"
objects. This architecture should make it easier to add optional or
experimental features, and maintain backwards compatibility.
* Fixes issues #75, #137, #206, #213, #215, #219, #223, #226, #230, #233, #238,
#239, #240, #241, #243, #244, #245, #252, #253, and other bugs. Thanks to
Thomas Waldmann and Alexei Gousev for the help!
Whoosh 2.3.2
============
* Fixes bug in BM25F scoring function, leading to increased precision in search
results.
* Fixes issues #203, #205, #206, #208, #209, #212.
Whoosh 2.3.1
============
* Fixes issue #200.
Whoosh 2.3
==========
* Added a :class:`whoosh.query.Regex` term query type, similar to
:class:`whoosh.query.Wildcard`. The parser does not allow regex term queries
by default. You need to add the :class:`whoosh.qparser.RegexPlugin` plugin.
After you add the plugin, you can use ``r"expression"`` query syntax for
regular expression term queries. For example, ``r"foo.*bar"``.
* Added the :class:`whoosh.qparser.PseudoFieldPlugin` parser plugin. This
plugin lets you create "pseudo-fields" that run a transform function on
whatever query syntax the user applies the field to. This is fairly advanced
functionality right now; I'm trying to think of ways to make its power easier
to access.
* The documents in the lists in the dictionary returned by ``Results.groups()``
by default are now in the same relative order as in the results. This makes
it much easier to display the "top N" results in each category, for example.
* The ``groupids`` keyword argument to ``Searcher.search`` has been removed.
Instead you can now pass a :class:`whoosh.sorting.FacetMap` object to the
``Searcher.search`` method's ``maptype`` argument to control how faceted
documents are grouped, and/or set the ``maptype`` argument on individual
:class:`whoosh.sorting.FacetType`` objects to set custom grouping per facet.
See :doc:`../facets` for more information.
* Calling ``Searcher.documents()`` or ``Searcher.document_numbers()`` with no
arguments now yields all documents/numbers.
* Calling ``Writer.update_document()`` with no unique fields is now equivalent
to calling ``Writer.add_document()`` with the same arguments.
* Fixed a problem with keyword expansion where the code was building a cache
that was fast on small indexes, but unacceptably slow on large indexes.
* Added the hyphen (``-``) to the list of characters that match a "wildcard"
token, to make parsing slightly more predictable. A true fix will have to
wait for another parser rewrite.
* Fixed an unused ``__future__`` import and use of ``float("nan")`` which were
breaking under Python 2.5.
* Fixed a bug where vectored fields with only one term stored an empty term
vector.
* Various other bug fixes.
Whoosh 2.2
==========
* Fixes several bugs, including a bad bug in BM25F scoring.
* Added ``allow_overlap`` option to :class:`whoosh.sorting.StoredFieldFacet`.
* In :meth:`~whoosh.writing.IndexWriter.add_document`, You can now pass
query-like strings for BOOLEAN and DATETIME fields (e.g ``boolfield="true"``
and ``dtfield="20101131-16:01"``) as an alternative to actual ``bool`` or
``datetime`` objects. The implementation of this is incomplete: it only works
in the default ``filedb`` backend, and if the field is stored, the stored
value will be the string, not the parsed object.
* Added :class:`whoosh.analysis.CompoundWordFilter` and
:class:`whoosh.analysis.TeeFilter`.
Whoosh 2.1
==========
This release fixes several bugs, and contains speed improvments to highlighting.
See :doc:`/highlight` for more information.
Whoosh 2.0
==========
Improvements
------------
* Whoosh is now compatible with Python 3 (tested with Python 3.2). Special
thanks to Vinay Sajip who did the work, and also Jordan Sherer who helped
fix later issues.
* Sorting and grouping (faceting) now use a new system of "facet" objects which
are much more flexible than the previous field-based system.
For example, to sort by first name and then score::
from whoosh import sorting
mf = sorting.MultiFacet([sorting.FieldFacet("firstname"),
sorting.ScoreFacet()])
results = searcher.search(myquery, sortedby=mf)
In addition to the previously supported sorting/grouping by field contents
and/or query results, you can now use numeric ranges, date ranges, score, and
more. The new faceting system also supports overlapping groups.
(The old "Sorter" API still works but is deprecated and may be removed in a
future version.)
See :doc:`/facets` for more information.
* Completely revamped spell-checking to make it much faster, easier, and more
flexible. You can enable generation of the graph files use by spell checking
using the ``spelling=True`` argument to a field type::
schema = fields.Schema(text=fields.TEXT(spelling=True))
(Spelling suggestion methods will work on fields without ``spelling=True``
but will slower.) The spelling graph will be updated automatically as new
documents are added -- it is no longer necessary to maintain a separate
"spelling index".
You can get suggestions for individual words using
:meth:`whoosh.searching.Searcher.suggest`::
suglist = searcher.suggest("content", "werd", limit=3)
Whoosh now includes convenience methods to spell-check and correct user
queries, with optional highlighting of corrections using the
``whoosh.highlight`` module::
from whoosh import highlight, qparser
# User query string
qstring = request.get("q")
# Parse into query object
parser = qparser.QueryParser("content", myindex.schema)
qobject = parser.parse(qstring)
results = searcher.search(qobject)
if not results:
correction = searcher.correct_query(gobject, gstring)
# correction.query = corrected query object
# correction.string = corrected query string
# Format the corrected query string with HTML highlighting
cstring = correction.format_string(highlight.HtmlFormatter())
Spelling suggestions can come from field contents and/or lists of words.
For stemmed fields the spelling suggestions automatically use the unstemmed
forms of the words.
There are APIs for spelling suggestions and query correction, so highly
motivated users could conceivably replace the defaults with more
sophisticated behaviors (for example, to take context into account).
See :doc:`/spelling` for more information.
* :class:`whoosh.query.FuzzyTerm` now uses the new word graph feature as well
and so is much faster.
* You can now set a boost factor for individual documents as you index them,
to increase the score of terms in those documents in searches. See the
documentation for the :meth:`~whoosh.writing.IndexWriter.add_document` for
more information.
* Added built-in recording of which terms matched in which documents. Use the
``terms=True`` argument to :meth:`whoosh.searching.Searcher.search` and use
:meth:`whoosh.searching.Hit.matched_terms` and
:meth:`whoosh.searching.Hit.contains_term` to check matched terms.
* Whoosh now supports whole-term quality optimizations, so for example if the
system knows that a UnionMatcher cannot possibly contribute to the "top N"
results unless both sub-matchers match, it will replace the UnionMatcher with
an IntersectionMatcher which is faster to compute. The performance improvement
is not as dramatic as from block quality optimizations, but it can be
noticeable.
* Fixed a bug that prevented block quality optimizations in queries with words
not in the index, which could severely degrade performance.
* Block quality optimizations now use the actual scoring algorithm to calculate
block quality instead of an approximation, which fixes issues where ordering
of results could be different for searches with and without the optimizations.
* the BOOLEAN field type now supports field boosts.
* Re-architected the query parser to make the code easier to understand. Custom
parser plugins from previous versions will probably break in Whoosh 2.0.
* Various bug-fixes and performance improvements.
* Removed the "read lock", which caused more problems than it solved. Now when
opening a reader, if segments are deleted out from under the reader as it
is opened, the code simply retries.
Compatibility
-------------
* The term quality optimizations required changes to the on-disk formats.
Whoosh 2.0 if backwards-compatible with the old format. As you rewrite an
index using Whoosh 2.0, by default it will use the new formats for new
segments, making the index incompatible with older versions.
To upgrade an existing index to use the new formats immediately, use
``Index.optimize()``.
* Removed the experimental ``TermTrackingCollector`` since it is replaced by
the new built-in term recording functionality.
* Removed the experimental ``Searcher.define_facets`` feature until a future
release when it will be replaced by a more robust and useful feature.
* Reader iteration methods (``__iter__``, ``iter_from``, ``iter_field``, etc.)
now yield :class:`whoosh.reading.TermInfo` objects.
* The arguments to :class:`whoosh.query.FuzzyTerm` changed.
