def get_indexed_slices(self, index_clause, columns=None, column_start="", column_finish="",
column_reversed=False, column_count=100, include_timestamp=False,
read_consistency_level=None, buffer_size=None):
"""
Similar to :meth:`get_range()`, but an :class:`~pycassa.cassandra.ttypes.IndexClause`
is used instead of a key range.
`index_clause` limits the keys that are returned based on expressions
that compare the value of a column to a given value. At least one of the
expressions in the :class:`.IndexClause` must be on an indexed column.
Note that Cassandra does not support secondary indexes or get_indexed_slices()
for super column families.
.. seealso:: :meth:`~pycassa.index.create_index_clause()` and
:meth:`~pycassa.index.create_index_expression()`
"""
assert not self.super, "get_indexed_slices() is not " \
"supported by super column families"
cl = read_consistency_level or self.read_consistency_level
cp = self._column_parent()
sp = self._slice_predicate(columns, column_start, column_finish,
column_reversed, column_count)
new_exprs = []
# Pack the values in the index clause expressions
for expr in index_clause.expressions:
name = self._pack_name(expr.column_name)
value = self._pack_value(expr.value, name)
new_exprs.append(IndexExpression(name, expr.op, value))
packed_start_key = self._pack_key(index_clause.start_key)
clause = IndexClause(new_exprs, packed_start_key, index_clause.count)
# Figure out how we will chunk the request
if buffer_size is None:
buffer_size = self.buffer_size
row_count = clause.count
count = 0
i = 0
last_key = clause.start_key
while True:
if row_count is not None:
buffer_size = min(row_count - count + 1, buffer_size)
clause.count = buffer_size
clause.start_key = last_key
key_slices = self.pool.execute('get_indexed_slices', cp, clause, sp, cl)
if key_slices is None:
return
for j, key_slice in enumerate(key_slices):
# Ignore the first element after the first iteration
# because it will be a duplicate.
if j == 0 and i != 0:
continue
unpacked_key = self._unpack_key(key_slice.key)
yield (unpacked_key,
self._cosc_to_dict(key_slice.columns, include_timestamp))
count += 1
if row_count is not None and count >= row_count:
return
if len(key_slices) != buffer_size:
return
last_key = key_slices[-1].key
i += 1
def get_indexed_slices(self, index_clause, columns=None, column_start="", column_finish="",
column_reversed=False, column_count=100, include_timestamp=False,
super_column=None, read_consistency_level=None,
buffer_size=None):
"""
Fetches a set of rows from this column family based on an index clause.
:param index_clause: Limits the keys that are returned based on expressions
that compare the value of a column to a given value. At least one of the
expressions in the :class:`.IndexClause` must be on an indexed column.
.. seealso:: :meth:`~pycassa.index.create_index_clause()` and
:meth:`~pycassa.index.create_index_expression()`
:type index_clause: :class:`~pycassa.cassandra.ttypes.IndexClause`
:param columns: Limit the columns or super columns fetched to the specified list
:type columns: list
:param column_start: Only fetch columns or super columns ``>= column_start``
:param column_finish: Only fetch columns or super columns ``<= column_finish``
:param column_reversed:
Fetch the columns or super_columns in reverse order. If `column_count` is
used with this, columns will be drawn from the end. The returned dictionary
of columns may not be in reversed order if an ordered ``dict_class`` is not
passed to the constructor.
:type column_reversed: bool
:param column_count: Limit the number of columns or super columns fetched per row
:param include_timestamp: If True, return a ``(value, timestamp)`` tuple for each column
:type include_timestamp: bool
:param super_column: Return columns only in this super column
:param read_consistency_level: Affects the guaranteed replication factor before
returning from any read operation
:type read_consistency_level: :class:`~pycassa.cassandra.ttypes.ConsistencyLevel`
:param buffer_size: When calling `get_indexed_slices()`, the intermediate
results need to be buffered if we are fetching many rows, otherwise the Cassandra
server will overallocate memory and fail. This is the size of
that buffer in number of rows. If left as ``None``,
the :class:`~pycassa.cassandra.ColumnFamily`'s default
`buffer_size` will be used.
:type buffer_size: int
:rtype: Generator that iterates over:
``{key : {column_name : column_value}}``
"""
cp = self._create_column_parent(super_column)
sp = self._create_slice_predicate(columns, column_start, column_finish,
column_reversed, column_count)
new_exprs = []
# Pack the values in the index clause expressions
for expr in index_clause.expressions:
new_exprs.append(IndexExpression(self._pack_name(expr.column_name),
expr.op,
self._pack_value(expr.value, expr.column_name)))
clause = IndexClause(new_exprs, index_clause.start_key, index_clause.count)
# Figure out how we will chunk the request
if buffer_size is None:
buffer_size = self.buffer_size
row_count = clause.count
count = 0
i = 0
last_key = clause.start_key
while True:
if row_count is not None:
buffer_size = min(row_count - count + 1, buffer_size)
clause.count = buffer_size
clause.start_key = last_key
key_slices = self.client.get_indexed_slices(cp, clause, sp,
self._rcl(read_consistency_level))
if key_slices is None:
return
for j, key_slice in enumerate(key_slices):
# Ignore the first element after the first iteration
# because it will be a duplicate.
if j == 0 and i != 0:
continue
yield (key_slice.key, self._convert_ColumnOrSuperColumns_to_dict_class(
key_slice.columns, include_timestamp))
count += 1
if row_count is not None and count >= row_count:
return
if len(key_slices) != buffer_size:
return
last_key = key_slices[-1].key
i += 1
def get_indexed_slices(self, index_clause, columns=None, column_start="", column_finish="",
column_reversed=False, column_count=100, include_timestamp=False,
read_consistency_level=None, buffer_size=None, include_ttl=False):
"""
Similar to :meth:`get_range()`, but an :class:`~pycassa.cassandra.ttypes.IndexClause`
is used instead of a key range.
`index_clause` limits the keys that are returned based on expressions
that compare the value of a column to a given value. At least one of the
expressions in the :class:`.IndexClause` must be on an indexed column.
Note that Cassandra does not support secondary indexes or get_indexed_slices()
for super column families.
.. seealso:: :meth:`~pycassa.index.create_index_clause()` and
:meth:`~pycassa.index.create_index_expression()`
"""
assert not self.super, "get_indexed_slices() is not " \
"supported by super column families"
cl = read_consistency_level or self.read_consistency_level
cp = self._column_parent()
sp = self._slice_predicate(columns, column_start, column_finish,
column_reversed, column_count)
new_exprs = []
# Pack the values in the index clause expressions
for expr in index_clause.expressions:
value = self._pack_value(expr.value, expr.column_name)
name = self._pack_name(expr.column_name)
new_exprs.append(IndexExpression(name, expr.op, value))
packed_start_key = self._pack_key(index_clause.start_key)
clause = IndexClause(new_exprs, packed_start_key, index_clause.count)
# Figure out how we will chunk the request
if buffer_size is None:
buffer_size = self.buffer_size
row_count = clause.count
count = 0
i = 0
last_key = clause.start_key
while True:
if row_count is not None:
if i == 0 and row_count <= buffer_size:
# We don't need to chunk, grab exactly the number of rows
buffer_size = row_count
else:
buffer_size = min(row_count - count + 1, buffer_size)
clause.count = buffer_size
clause.start_key = last_key
key_slices = self.pool.execute('get_indexed_slices', cp, clause, sp, cl)
if key_slices is None:
return
for j, key_slice in enumerate(key_slices):
# Ignore the first element after the first iteration
# because it will be a duplicate.
if j == 0 and i != 0:
continue
unpacked_key = self._unpack_key(key_slice.key)
yield (unpacked_key,
self._cosc_to_dict(key_slice.columns, include_timestamp, include_ttl))
count += 1
if row_count is not None and count >= row_count:
return
if len(key_slices) != buffer_size:
return
last_key = key_slices[-1].key
i += 1
def get_indexed_slices(self,
index_clause,
columns=None,
column_start="",
column_finish="",
column_reversed=False,
column_count=100,
include_timestamp=False,
read_consistency_level=None,
buffer_size=None):
"""
Similar to :meth:`get_range()`, but an :class:`~pycassa.cassandra.ttypes.IndexClause`
is used instead of a key range.
`index_clause` limits the keys that are returned based on expressions
that compare the value of a column to a given value. At least one of the
expressions in the :class:`.IndexClause` must be on an indexed column.
Note that Cassandra does not support secondary indexes or get_indexed_slices()
for super column families.
.. seealso:: :meth:`~pycassa.index.create_index_clause()` and
:meth:`~pycassa.index.create_index_expression()`
"""
assert not self.super, "get_indexed_slices() is not " \
"supported by super column families"
cp = self._create_column_parent()
sp = self._create_slice_predicate(columns, column_start, column_finish,
column_reversed, column_count)
new_exprs = []
# Pack the values in the index clause expressions
for expr in index_clause.expressions:
name = self._pack_name(expr.column_name)
value = self._pack_value(expr.value, name)
new_exprs.append(IndexExpression(name, expr.op, value))
clause = IndexClause(new_exprs, index_clause.start_key,
index_clause.count)
# Figure out how we will chunk the request
if buffer_size is None:
buffer_size = self.buffer_size
row_count = clause.count
count = 0
i = 0
last_key = clause.start_key
while True:
if row_count is not None:
buffer_size = min(row_count - count + 1, buffer_size)
clause.count = buffer_size
clause.start_key = last_key
try:
self._obtain_connection()
key_slices = self._tlocal.client.get_indexed_slices(
cp, clause, sp, self._rcl(read_consistency_level))
finally:
self._release_connection()
if key_slices is None:
return
for j, key_slice in enumerate(key_slices):
# Ignore the first element after the first iteration
# because it will be a duplicate.
if j == 0 and i != 0:
continue
yield (key_slice.key,
self._convert_ColumnOrSuperColumns_to_dict_class(
key_slice.columns, include_timestamp))
count += 1
if row_count is not None and count >= row_count:
return
if len(key_slices) != buffer_size:
return
last_key = key_slices[-1].key
i += 1