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77 lines
2.7 KiB
Python
77 lines
2.7 KiB
Python
# Copyright 2019 Elasticsearch BV
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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class Index:
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"""
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The index for an eland.DataFrame.
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TODO - This currently has very different behaviour than pandas.Index
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Currently, the index is a field that exists in every document in an Elasticsearch index.
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For slicing and sorting operations it must be a docvalues field. By default _id is used,
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which can't be used for range queries and is inefficient for sorting:
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https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-id-field.html
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(The value of the _id field is also accessible in aggregations or for sorting,
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but doing so is discouraged as it requires to load a lot of data in memory.
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In case sorting or aggregating on the _id field is required, it is advised to duplicate
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the content of the _id field in another field that has doc_values enabled.)
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"""
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ID_INDEX_FIELD = '_id'
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ID_SORT_FIELD = '_doc' # if index field is _id, sort by _doc
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def __init__(self, query_compiler, index_field=None):
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self.index_field = index_field
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self._query_compiler = query_compiler
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@property
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def sort_field(self):
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if self._index_field == self.ID_INDEX_FIELD:
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return self.ID_SORT_FIELD
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return self._index_field
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@property
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def is_source_field(self):
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return self._is_source_field
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@property
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def index_field(self):
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return self._index_field
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@index_field.setter
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def index_field(self, index_field):
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if index_field is None or index_field == Index.ID_INDEX_FIELD:
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self._index_field = Index.ID_INDEX_FIELD
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self._is_source_field = False
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else:
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self._index_field = index_field
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self._is_source_field = True
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def __len__(self):
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return self._query_compiler._index_count()
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# Make iterable
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def __next__(self):
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# TODO resolve this hack to make this 'iterable'
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raise StopIteration()
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def __iter__(self):
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return self
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def info_es(self, buf):
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buf.write("Index:\n")
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buf.write(" index_field: {0}\n".format(self.index_field))
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buf.write(" is_source_field: {0}\n".format(self.is_source_field))
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